Our Labs
The Blish Lab
The Blish laboratory is in the Department of Medicine, Division of Infectious Diseases and Geographic Medicine and in the interdisciplinary Stanford Immunology program. Our goal is to develop new methods to prevent and control infectious diseases through better understanding of human immunology. We have several major areas of ongoing investigation.
Publications
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Zika Virus Infection Induces Cranial Neural Crest Cells to Produce Cytokines at Levels Detrimental for Neurogenesis.
Cell host & microbe
Bayless, N. L., Greenberg, R. S., Swigut, T., Wysocka, J., Blish, C. A.
2016; 20 (4): 423-428
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Abstract
Zika virus (ZIKV) infection during pregnancy is linked to microcephaly, which is attributed to infection of developing brain structures. ZIKV infects neural progenitor cells in vitro, though its effects on other developmentally relevant stem cell populations, including cranial neural crest cells (CNCCs), have not been assessed. CNCCs give rise to most cranial bones and exert paracrine effects on the developing brain. Here, we report that CNCCs are productively infected by ZIKV, but not by the related dengue virus. ZIKV-infected CNCCs undergo limited apoptosis but secrete cytokines that promote death and drive aberrant differentiation of neural progenitor cultures. Addition of two such cytokines, LIF or VEGF, at levels comparable to those secreted by ZIKV-infected CNCCs is sufficient to recapitulate premature neuronal differentiation and apoptotic death of neural progenitors. Thus, our results suggest that CNCC infection by ZIKV may contribute to associated embryopathies through signaling crosstalk between developing face and brain structures.
View details for DOI 10.1016/j.chom.2016.09.006
View details for PubMedID 27693308
View details for PubMedCentralID PMC5113290
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Human NK cell repertoire diversity reflects immune experience and correlates with viral susceptibility.
Science translational medicine
Strauss-Albee, D. M., Fukuyama, J., Liang, E. C., Yao, Y., Jarrell, J. A., Drake, A. L., Kinuthia, J., Montgomery, R. R., John-Stewart, G., Holmes, S., Blish, C. A.
2015; 7 (297): 297ra115-?
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Abstract
Innate natural killer (NK) cells are diverse at the single-cell level because of variegated expressions of activating and inhibitory receptors, yet the developmental roots and functional consequences of this diversity remain unknown. Because NK cells are critical for antiviral and antitumor responses, a better understanding of their diversity could lead to an improved ability to harness them therapeutically. We found that NK diversity is lower at birth than in adults. During an antiviral response to either HIV-1 or West Nile virus, NK diversity increases, resulting in terminal differentiation and cytokine production at the cost of cell division and degranulation. In African women matched for HIV-1 exposure risk, high NK diversity is associated with increased risk of HIV-1 acquisition. Existing diversity may therefore decrease the flexibility of the antiviral response. Collectively, the data reveal that human NK diversity is a previously undefined metric of immune history and function that may be clinically useful in forecasting the outcomes of infection and malignancy.
View details for DOI 10.1126/scitranslmed.aac5722
View details for PubMedID 26203083
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Enhanced natural killer-cell and T-cell responses to influenza A virus during pregnancy.
Proceedings of the National Academy of Sciences of the United States of America
Kay, A. W., Fukuyama, J., Aziz, N., Dekker, C. L., Mackey, S., Swan, G. E., Davis, M. M., Holmes, S., Blish, C. A.
2014; 111 (40): 14506-14511
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Abstract
Pregnant women experience increased morbidity and mortality after influenza infection, for reasons that are not understood. Although some data suggest that natural killer (NK)- and T-cell responses are suppressed during pregnancy, influenza-specific responses have not been previously evaluated. Thus, we analyzed the responses of women that were pregnant (n = 21) versus those that were not (n = 29) immediately before inactivated influenza vaccination (IIV), 7 d after vaccination, and 6 wk postpartum. Expression of CD107a (a marker of cytolysis) and production of IFN-γ and macrophage inflammatory protein (MIP) 1β were assessed by flow cytometry. Pregnant women had a significantly increased percentage of NK cells producing a MIP-1β response to pH1N1 virus compared with nonpregnant women pre-IIV [median, 6.66 vs. 0.90% (P = 0.0149)] and 7 d post-IIV [median, 11.23 vs. 2.81% (P = 0.004)], indicating a heightened chemokine response in pregnant women that was further enhanced by the vaccination. Pregnant women also exhibited significantly increased T-cell production of MIP-1β and polyfunctionality in NK and T cells to pH1N1 virus pre- and post-IIV. NK- and T-cell polyfunctionality was also enhanced in pregnant women in response to the H3N2 viral strain. In contrast, pregnant women had significantly reduced NK- and T-cell responses to phorbol 12-myristate 13-acetate and ionomycin. This type of stimulation led to the conclusion that NK- and T-cell responses during pregnancy are suppressed, but clearly this conclusion is not correct relative to the more biologically relevant assays described here. Robust cellular immune responses to influenza during pregnancy could drive pulmonary inflammation, explaining increased morbidity and mortality.
View details for DOI 10.1073/pnas.1416569111
View details for PubMedID 25246558
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Genetic and environmental determinants of human NK cell diversity revealed by mass cytometry.
Science translational medicine
Horowitz, A., Strauss-Albee, D. M., Leipold, M., Kubo, J., Nemat-Gorgani, N., Dogan, O. C., Dekker, C. L., Mackey, S., Maecker, H., Swan, G. E., Davis, M. M., Norman, P. J., Guethlein, L. A., Desai, M., Parham, P., Blish, C. A.
2013; 5 (208): 208ra145-?
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View details for DOI 10.1126/scitranslmed.3006702
View details for PubMedID 24154599
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The newborn human NK cell repertoire is phenotypically formed but functionally reduced
CYTOMETRY PART B-CLINICAL CYTOMETRY
Strauss-Albee, D. M., Liang, E. C., Ranganath, T., Aziz, N., Blish, C. A.
2017; 92 (1): 33-41
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View details for DOI 10.1002/cyto.b.21485
View details for Web of Science ID 000394980300005
The Einav Lab
The goals of our lab are to better understand virus-host protein interactions, identify host proteins or pathways required by multiple viruses, and translate this knowledge into the development of novel, broad-spectrum, host-centered antiviral approaches with a high genetic barrier for resistance.
Publications
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Interactions between the Hepatitis C Virus Nonstructural 2 Protein and Host Adaptor Proteins 1 and 4 Orchestrate Virus Release.
mBio
Xiao, F., Wang, S., Barouch-Bentov, R., Neveu, G., Pu, S., Beer, M., Schor, S., Kumar, S., Nicolaescu, V., Lindenbach, B. D., Randall, G., Einav, S.
2018; 9 (2)
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Abstract
Hepatitis C virus (HCV) spreads via secreted cell-free particles or direct cell-to-cell transmission. Yet, virus-host determinants governing differential intracellular trafficking of cell-free- and cell-to-cell-transmitted virus remain unknown. The host adaptor proteins (APs) AP-1A, AP-1B, and AP-4 traffic in post-Golgi compartments, and the latter two are implicated in basolateral sorting. We reported that AP-1A mediates HCV trafficking during release, whereas the endocytic adaptor AP-2 mediates entry and assembly. We demonstrated that the host kinases AAK1 and GAK regulate HCV infection by controlling these clathrin-associated APs. Here, we sought to define the roles of AP-4, a clathrin-independent adaptor; AP-1A; and AP-1B in HCV infection. We screened for interactions between HCV proteins and the μ subunits of AP-1A, AP-1B, and AP-4 by mammalian cell-based protein fragment complementation assays. The nonstructural 2 (NS2) protein emerged as an interactor of these adaptors in this screening and by coimmunoprecipitations in HCV-infected cells. Two previously unrecognized dileucine-based motifs in the NS2 C terminus mediated AP binding and HCV release. Infectivity and coculture assays demonstrated that while all three adaptors mediate HCV release and cell-free spread, AP-1B and AP-4, but not AP-1A, mediate cell-to-cell spread. Live-cell imaging revealed HCV cotrafficking with AP-1A, AP-1B, and AP-4 and that AP-4 mediates HCV trafficking in a post-Golgi compartment. Lastly, HCV cell-to-cell spread was regulated by AAK1 and GAK and thus susceptible to treatment with AAK1 and GAK inhibitors. These data provide a mechanistic understanding of HCV trafficking in distinct release pathways and reveal a requirement for APs in cell-to-cell viral spread.IMPORTANCE HCV spreads via cell-free infection or cell-to-cell contact that shields it from antibody neutralization, thereby facilitating viral persistence. Yet, factors governing this differential sorting remain unknown. By integrating proteomic, RNA interference, genetic, live-cell imaging, and pharmacological approaches, we uncover differential coopting of host adaptor proteins (APs) to mediate HCV traffic at distinct late steps of the viral life cycle. We reported that AP-1A and AP-2 mediate HCV trafficking during release and assembly, respectively. Here, we demonstrate that dileucine motifs in the NS2 protein mediate AP-1A, AP-1B, and AP-4 binding and cell-free virus release. Moreover, we reveal that AP-4, an adaptor not previously implicated in viral infections, mediates cell-to-cell spread and HCV trafficking. Lastly, we demonstrate cell-to-cell spread regulation by AAK1 and GAK, host kinases controlling APs, and susceptibility to their inhibitors. This study provides mechanistic insights into virus-host determinants that facilitate HCV trafficking, with potential implications for pathogenesis and antiviral agent design.
View details for DOI 10.1128/mBio.02233-17
View details for PubMedID 29535204
View details for PubMedCentralID PMC5850324
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Turning Up Your Nose for a Flaviviral Encephalitis Cure.
Cell host & microbe
Barouch-Bentov, R., Einav, S.
2018; 23 (4): 427–29
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Abstract
siRNA approaches have demonstrated promise in treating viral infections in animal models, but poor delivery limits clinical application. In this issue of Cell Host & Microbe, Beloor et al. (2018) report that nose-to-brain delivery of viral-targeted siRNA cures mice from West Nile virus encephalitis, with potential implications for human infection.
View details for DOI 10.1016/j.chom.2018.03.014
View details for PubMedID 29649437
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Single-cell transcriptional dynamics of flavivirus infection.
eLife
Zanini, F., Pu, S. Y., Bekerman, E., Einav, S., Quake, S. R.
2018; 7
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Abstract
Dengue and Zika viral infections affect millions of people annually and can be complicated by hemorrhage and shock or neurological manifestations, respectively. However, a thorough understanding of the host response to these viruses is lacking, partly because conventional approaches ignore heterogeneity in virus abundance across cells. We present viscRNA-Seq (virus-inclusive single cell RNA-Seq), an approach to probe the host transcriptome together with intracellular viral RNA at the single cell level. We applied viscRNA-Seq to monitor dengue and Zika virus infection in cultured cells and discovered extreme heterogeneity in virus abundance. We exploited this variation to identify host factors that show complex dynamics and a high degree of specificity for either virus, including proteins involved in the endoplasmic reticulum translocon, signal peptide processing, and membrane trafficking. We validated the viscRNA-Seq hits and discovered novel proviral and antiviral factors. viscRNA-Seq is a powerful approach to assess the genome-wide virus-host dynamics at single cell level.
View details for DOI 10.7554/eLife.32942
View details for PubMedID 29451494
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Combating Intracellular Pathogens with Repurposed Host-Targeted Drugs.
ACS infectious diseases
Schor, S., Einav, S.
2018; 4 (2): 88–92
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Abstract
There is a large, global unmet need for the development of countermeasures to combat intracellular pathogens. The development of novel antimicrobials is expensive and slow and typically focuses on selective inhibition of proteins encoded by a single pathogen, thereby providing a narrow spectrum of coverage. The repurposing of approved drugs targeting host functions required for microbial infections represents a promising alternative. This review summarizes progress and challenges in the repurposing of approved drugs as host-targeted broad-spectrum agents for the treatment of intracellular pathogens. These strategies include targeting both cellular factors required for infection by various viruses, intracellular bacteria, and/or protozoa as well as factors that modulate the host immune response to these microbial infections. The repurposed approach offers complementary means to develop therapeutics against existing and emerging intracellular microbial threats.
View details for DOI 10.1021/acsinfecdis.7b00268
View details for PubMedID 29298032
View details for PubMedCentralID PMC5807128
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Anticancer kinase inhibitors impair intracellular viral trafficking and exert broad-spectrum antiviral effects
JOURNAL OF CLINICAL INVESTIGATION
Bekerman, E., Neveu, G., Shulla, A., Brannan, J., Pu, S., Wang, S., Xiao, F., Barouch-Bentov, R., Bakken, R. R., Mateo, R., Govero, J., Nagamine, C. M., Diamond, M. S., De Jonghe, S., Herdewijn, P., Dye, J. M., Randall, G., Einav, S.
2017; 127 (4): 1338-1352
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Abstract
Global health is threatened by emerging viral infections, which largely lack effective vaccines or therapies. Targeting host pathways that are exploited by multiple viruses could offer broad-spectrum solutions. We previously reported that AAK1 and GAK, kinase regulators of the host adaptor proteins AP1 and AP2, are essential for hepatitis C virus (HCV) infection, but the underlying mechanism and relevance to other viruses or in vivo infections remained unknown. Here, we have discovered that AP1 and AP2 cotraffic with HCV particles in live cells. Moreover, we found that multiple viruses, including dengue and Ebola, exploit AAK1 and GAK during entry and infectious virus production. In cultured cells, treatment with sunitinib and erlotinib, approved anticancer drugs that inhibit AAK1 or GAK activity, or with more selective compounds inhibited intracellular trafficking of HCV and multiple unrelated RNA viruses with a high barrier to resistance. In murine models of dengue and Ebola infection, sunitinib/erlotinib combination protected against morbidity and mortality. We validated sunitinib- and erlotinib-mediated inhibition of AAK1 and GAK activity as an important mechanism of antiviral action. Additionally, we revealed potential roles for additional kinase targets. These findings advance our understanding of virus-host interactions and establish a proof of principle for a repurposed, host-targeted approach to combat emerging viruses.
View details for DOI 10.1172/JCI89857
View details for Web of Science ID 000398183300024
View details for PubMedID 28240606
The Parsonnet Lab
The laboratory's primary research interest is investigating the role of infectious agents in chronic diseases. Much of this work has revolved around Helicobacter pylori infection as a cause of adenocarcinomas and lymphomas of the stomach.
Publications
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Crossover Control Study of the Effect of Personal Care Products Containing Triclosan on the Microbiome.
mSphere
Poole, A. C., Pischel, L., Ley, C., Suh, G., Goodrich, J. K., Haggerty, T. D., Ley, R. E., Parsonnet, J.
2016; 1 (3)
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Abstract
Commonly prescribed antibiotics are known to alter human microbiota. We hypothesized that triclosan and triclocarban, components of many household and personal care products (HPCPs), may alter the oral and gut microbiota, with potential consequences for metabolic function and weight. In a double-blind, randomized, crossover study, participants were given triclosan- and triclocarban (TCS)-containing or non-triclosan/triclocarban (nTCS)-containing HPCPs for 4 months and then switched to the other products for an additional 4 months. Blood, stool, gingival plaque, and urine samples and weight data were obtained at baseline and at regular intervals throughout the study period. Blood samples were analyzed for metabolic and endocrine markers and urine samples for triclosan. The microbiome in stool and oral samples was then analyzed. Although there was a significant difference in the amount of triclosan in the urine between the TCS and nTCS phases, no differences were found in microbiome composition, metabolic or endocrine markers, or weight. Though this study was limited by the small sample size and imprecise administration of HPCPs, triclosan at physiologic levels from exposure to HPCPs does not appear to have a significant or important impact on human oral or gut microbiome structure or on a panel of metabolic markers. IMPORTANCE Triclosan and triclocarban are commonly used commercial microbicides found in toothpastes and soaps. It is unknown what effects these chemicals have on the human microbiome or on endocrine function. From this randomized crossover study, it appears that routine personal care use of triclosan and triclocarban neither exerts a major influence on microbial communities in the gut and mouth nor alters markers of endocrine function in humans.
View details for DOI 10.1128/mSphere.00056-15
View details for PubMedID 27303746
View details for PubMedCentralID PMC4888890
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Effect of long-term antibiotic use on weight in adolescents with acne.
journal of antimicrobial chemotherapy
Contopoulos-Ioannidis, D. G., Ley, C., Wang, W., Ma, T., Olson, C., Shi, X., Luft, H. S., Hastie, T., Parsonnet, J.
2016; 71 (4): 1098-1105
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Abstract
Antibiotics increase weight in farm animals and may cause weight gain in humans. We used electronic health records from a large primary care organization to determine the effect of antibiotics on weight and BMI in healthy adolescents with acne.We performed a retrospective cohort study of adolescents with acne prescribed ≥4 weeks of oral antibiotics with weight measurements within 18 months pre-antibiotics and 12 months post-antibiotics. We compared within-individual changes in weight-for-age Z-scores (WAZs) and BMI-for-age Z-scores (BMIZs). We used: (i) paired t-tests to analyse changes between the last pre-antibiotics versus the first post-antibiotic measurements; (ii) piecewise-constant-mixed models to capture changes between mean measurements pre- versus post-antibiotics; (iii) piecewise-linear-mixed models to capture changes in trajectory slopes pre- versus post-antibiotics; and (iv) χ(2) tests to compare proportions of adolescents with ≥0.2 Z-scores WAZ or BMIZ increase or decrease.Our cohort included 1012 adolescents with WAZs; 542 also had BMIZs. WAZs decreased post-antibiotics in all analyses [change between last WAZ pre-antibiotics versus first WAZ post-antibiotics = -0.041 Z-scores (P < 0.001); change between mean WAZ pre- versus post-antibiotics = -0.050 Z-scores (P < 0.001); change in WAZ trajectory slopes pre- versus post-antibiotics = -0.025 Z-scores/6 months (P = 0.002)]. More adolescents had a WAZ decrease post-antibiotics ≥0.2 Z-scores than an increase (26% versus 18%; P < 0.001). Trends were similar, though not statistically significant, for BMIZ changes.Contrary to original expectations, long-term antibiotic use in healthy adolescents with acne was not associated with weight gain. This finding, which was consistent across all analyses, does not support a weight-promoting effect of antibiotics in adolescents.
View details for DOI 10.1093/jac/dkv455
View details for PubMedID 26782773
View details for PubMedCentralID PMC4790625
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Stanford's Outcomes Research in Kids (STORK): a prospective study of healthy pregnant women and their babies in Northern California.
BMJ open
Ley, C., Sanchez, M. d., Mathur, A., Yang, S., Sundaram, V., Parsonnet, J.
2016; 6 (4)
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Abstract
Stanford's Outcomes Research in Kids (STORK) is an ongoing prospective cohort of healthy pregnant women and their babies established to determine the effect of infectious diseases on weight, linear growth and immune system development during childhood. Additionally, a nested randomised intervention of household and personal cleaning products tests the effects of the microbicides triclosan and triclocarban on these outcomes and incidence of infection.Healthy pregnant women were identified and enrolled primarily at public clinics; their babies, enrolled shortly after birth, are followed to age 36 months. Automated weekly surveys assess daily health status, infectious disease symptoms, healthcare provider visits and antibiotic use, in the mother during pregnancy and the baby once born. At 4-monthly household visits, information and samples are collected from the mother (urine, stool, saliva, skin swab), the baby (blood by heel/toe stick, urine, stool, saliva, skin swab) and the household (environmental swabs). Annual blood samples are obtained by venipuncture (mother and baby). Medical charts are abstracted for allergy and infectious illness in the mother during pregnancy and the baby.From 7/2011 to 2/2015, 158 mothers were enrolled at approximately 20 weeks gestation; 127 babies were enrolled. Two-thirds of mothers are Hispanic, one-third are non-US born and one-third speak primarily Spanish; mean years of education is 13 (SD 6.2) years. Households have on average 4.5 residents. Most households (97%) were randomised to participate in the intervention. Completion of weekly surveys (86%) and follow-up (75% after 14 months) is excellent in this young, mobile population; collection of samples is ongoing with thousands of specimens stored.Enrolled babies will be followed until age 36 months (last anticipated visit: 07/2018) with medical chart review completed soon thereafter. All epidemiological information and samples will be available for collaborative hypothesis testing.NCT01442701; Pre-results.
View details for DOI 10.1136/bmjopen-2015-010810
View details for PubMedID 27075843
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Cultivation and Serological Characterization of a Human Theiler's-Like Cardiovirus Associated with Diarrheal Disease
JOURNAL OF VIROLOGY
Chiu, C. Y., Greninger, A. L., Chen, E. C., Haggerty, T. D., Parsonnet, J., Delwart, E., DeRisi, J. L., Ganem, D.
2010; 84 (9): 4407-4414
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Abstract
Cardioviruses (e.g., Theiler's murine encephalomyelitis virus [TMEV]) are members of the Picornaviridae family that cause myocarditis and encephalitis in rodents. Recently, several studies have identified human cardioviruses, including Saffold virus (SAFV) and a related virus named human TMEV-like cardiovirus (HTCV). At least eight cardiovirus genotypes are now recognized, with SAFV and most strains of HTCV belonging to genotypes 1 and 2, respectively; genotype 2 strains are the most common in the population. Although a genotype 3 cardiovirus has recently been cultured (SAFV-3), the genotype 1 and 2 cardioviruses have been difficult to propagate in vitro, hindering efforts to understand their seroprevalence and pathogenicity. Here we present the isolation and characterization of a genotype 2 human cardiovirus (HTCV-UC6). Notably, successful cultivation of HTCV-UC6 from stool required the addition of cytokine-blocking antibodies to interrupt downstream antiviral pathways. Unlike SAFV-3, HTCV-UC6 exhibited slow replication kinetics and demonstrated only a moderate cytopathic effect. Serologic assays revealed that 91% of U.S. adults carry antibodies to the genotype 2 cardioviruses, of which 80% generate neutralizing antibodies, in agreement with previous data showing that cardiovirus infection is widespread in humans. We also demonstrate an acute cardiovirus seroconversion event in a child with diarrhea and vomiting, thus reporting for the first time evidence linking cardiovirus infection to diarrheal disease in humans.
View details for DOI 10.1128/JVI.02536-09
View details for Web of Science ID 000276358000027
View details for PubMedID 20164225
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Infection with Helicobacter pylori Is Associated with Protection against Tuberculosis
PLOS ONE
Perry, S., de Jong, B. C., Solnick, J. V., Sanchez, M. d., Yang, S., Lin, P. L., Hansen, L. M., Talat, N., Hill, P. C., Hussain, R., Adegbola, R. A., Flynn, J., Canfield, D., Parsonnet, J.
2010; 5 (1)
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Abstract
Helicobacter pylori, a lifelong and typically asymptomatic infection of the stomach, profoundly alters gastric immune responses, and may benefit the host in protection against other pathogens. We explored the hypothesis that H. pylori contributes to the control of infection with Mycobacterium tuberculosis.We first examined M. tuberculosis-specific IFN-gamma and H. pylori antibody responses in 339 healthy Northern Californians undergoing routine tuberculin skin testing. Of 97 subjects (29%) meeting criteria for latent tuberculosis (TB) infection (LTBI), 45 (46%) were H. pylori seropositive. Subjects with LTBI who were H. pylori-seropositive had 1.5-fold higher TB antigen-induced IFN-gamma responses (p = 0.04, ANOVA), and a more Th-1 like cytokine profile in peripheral blood mononuclear cells, compared to those who were H. pylori seronegative. To explore an association between H. pylori infection and clinical outcome of TB exposure, we evaluated H. pylori seroprevalence in baseline samples from two high risk TB case-contact cohorts, and from cynomolgus macaques experimentally challenged with M. tuberculosis. Compared to 513 household contacts who did not progress to active disease during a median 24 months follow-up, 120 prevalent TB cases were significantly less likely to be H. pylori infected (AOR: 0.55, 95% CI 0.0.36-0.83, p = 0.005), though seroprevalence was not significantly different from non-progressors in 37 incident TB cases (AOR: 1.35 [95% CI 0.63-2.9] p = 0.44). Cynomolgus macaques with natural H. pylori infection were significantly less likely to progress to TB 6 to 8 months after M. tuberculosis challenge (RR: 0.31 [95% CI 0.12-0.80], p = 0.04).H. pylori infection may induce bystander effects that modify the risk of active TB in humans and non-human primates. That immunity to TB may be enhanced by exposure to other microbial agents may have important implications for vaccine development and disease control.
View details for DOI 10.1371/journal.pone.0008804
View details for Web of Science ID 000273779000030
View details for PubMedID 20098711
The Schoolnik Lab
The Schoolnik laboratory is directed by Gary K. Schoolnik, M.D., whose current research and scholarly interests are structure-function analysis of bacterial adhesion proteins and toxins; design and synthesis of synthetic antigens; immunobiology of human papillomaviruses.
Publications
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The competitive cost of antibiotic resistance in Mycobacterium tuberculosis
SCIENCE
Gagneux, S., Long, C. D., Small, P. M., Van, T., Schoolnik, G. K., Bohannan, B. J.
2006; 312 (5782): 1944-1946
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Abstract
Mathematical models predict that the future of the multidrug-resistant tuberculosis epidemic will depend on the fitness cost of drug resistance. We show that in laboratory-derived mutants of Mycobacterium tuberculosis, rifampin resistance is universally associated with a competitive fitness cost and that this cost is determined by the specific resistance mutation and strain genetic background. In contrast, we demonstrate that prolonged patient treatment can result in multidrug-resistant strains with no fitness defect and that strains with low- or no-cost resistance mutations are also the most frequent among clinical isolates.
View details for DOI 10.1126/science.1124410
View details for Web of Science ID 000238848100057
View details for PubMedID 16809538
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Expression profiling of host pathogen interactions: How Mycobacterium tuberculosis and the macrophage adapt to one another
MICROBES AND INFECTION
Schnappinger, D., Schoolnik, G. K., Ehrt, S.
2006; 8 (4): 1132-1140
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Abstract
It has recently become feasible to quantify all mRNAs encoded by the genomes of bacterial pathogens and their eukaryotic host cells and to apply this approach to study the interaction of Mycobacterium tuberculosis with its primary host cell, the macrophage. These studies helped to identify regulatory circuits which mediate adaptation of the M. tuberculosis transcriptome to intraphagosomal environments and stimulated hypotheses for the function of these circuits in human tuberculosis. The macrophage transcriptome reacts to infections with the induction of a pathogen-unspecific expression program as well as the induction of pathogen-specific expression signatures, both of which contribute to the immunologic activation of the infected cell. M. tuberculosis induced changes in the macrophage transcriptome are mediated by Toll-like receptor dependent and Toll-like receptor independent signal transduction pathways. This response is shaped by macrophage produced reactive nitrogen and oxygen molecules and affected by viability and virulence of the pathogen.
View details for DOI 10.1016/j.micinf.2005.10.027
View details for Web of Science ID 000237754100021
View details for PubMedID 16517202
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Identification and characterization of RbmA, a novel protein required for the development of rugose colony morphology and biofilm structure in Vibrio cholerae
JOURNAL OF BACTERIOLOGY
Fong, J. C., Karplus, K., SCHOOLNIK, G. K., Yildiz, F. H.
2006; 188 (3): 1049-1059
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Abstract
Phase variation between smooth and rugose colony variants of Vibrio cholerae is predicted to be important for the pathogen's survival in its natural aquatic ecosystems. The rugose variant forms corrugated colonies, exhibits increased levels of resistance to osmotic, acid, and oxidative stresses, and has an enhanced capacity to form biofilms. Many of these phenotypes are mediated in part by increased production of an exopolysaccharide termed VPS. In this study, we compared total protein profiles of the smooth and rugose variants using two-dimensional gel electrophoresis and identified one protein that is present at a higher level in the rugose variant. A mutation in the gene encoding this protein, which does not have any known homologs in the protein databases, causes cells to form biofilms that are more fragile and sensitive to sodium dodecyl sulfate than wild-type biofilms. The results indicate that the gene, termed rbmA (rugosity and biofilm structure modulator A), is required for rugose colony formation and biofilm structure integrity in V. cholerae. Transcription of rbmA is positively regulated by the response regulator VpsR but not VpsT.
View details for DOI 10.1128/JB.188.3.1049-1059.2006
View details for Web of Science ID 000234840800025
View details for PubMedID 16428409
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Evidence supporting predicted metabolic pathways for Vibrio cholerae: gene expression data and clinical tests
NUCLEIC ACIDS RESEARCH
Shi, J., Romero, P. R., Schoolnik, G. K., Spormann, A. M., Karp, P. D.
2006; 34 (8): 2438-2444
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Abstract
Vibrio cholerae, the etiological agent of the diarrheal illness cholera, can kill an infected adult in 24 h. V.cholerae lives as an autochthonous microbe in estuaries, rivers and coastal waters. A better understanding of its metabolic pathways will assist the development of more effective treatments and will provide a deeper understanding of how this bacterium persists in natural aquatic habitats. Using the completed V.cholerae genome sequence and PathoLogic software, we created VchoCyc, a pathway-genome database that predicted 171 likely metabolic pathways in the bacterium. We report here experimental evidence supporting the computationally predicted pathways. The evidence comes from microarray gene expression studies of V.cholerae in the stools of three cholera patients [D. S. Merrell, S. M. Butler, F. Qadri, N. A. Dolganov, A. Alam, M. B. Cohen, S. B. Calderwood, G. K. Schoolnik and A. Camilli (2002) Nature, 417, 642-645.], from gene expression studies in minimal growth conditions and LB rich medium, and from clinical tests that identify V.cholerae. Expression data provide evidence supporting 92 (53%) of the 171 pathways. The clinical tests provide evidence supporting seven pathways, with six pathways supported by both methods. VchoCyc provides biologists with a useful tool for analyzing this organism's metabolic and genomic information, which could lead to potential insights into new anti-bacterial agents. VchoCyc is available in the BioCyc database collection (http://BioCyc.org).
View details for DOI 10.1093/nar/gkl310
View details for Web of Science ID 000237697000037
View details for PubMedID 16682451
View details for PubMedCentralID PMC1458520
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Chitin induces natural competence in Vibrio cholerae
SCIENCE
Meibom, K. L., Blokesch, M., Dolganov, N. A., Wu, C. Y., Schoolnik, G. K.
2005; 310 (5755): 1824-1827
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Abstract
The mosaic-structured Vibrio cholerae genome points to the importance of horizontal gene transfer (HGT) in the evolution of this human pathogen. We showed that V. cholerae can acquire new genetic material by natural transformation during growth on chitin, a biopolymer that is abundant in aquatic habitats (e.g., from crustacean exoskeletons), where it lives as an autochthonous microbe. Transformation competence was found to require a type IV pilus assembly complex, a putative DNA binding protein, and three convergent regulatory cascades, which are activated by chitin, increasing cell density, and nutrient limitation, a decline in growth rate, or stress.
View details for DOI 10.1126/science.1120096
View details for Web of Science ID 000234093600049
View details for PubMedID 16357262
The Singh Lab
Our lab studies the molecular basis of pathogenesis of two medically important parasites, Toxoplasma gondii and Entamoeba histolytica. The work is aimed at understanding the virulence determinant that each parasite uses in causing disease, specifically how T. gondii evades the human immune response by converting to a dormant bradyzoite stage and how E. histolyticacauses invasive colonic and hepatic disease.
Publications
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Development of RNA Interference Trigger-Mediated Gene Silencing in Entamoeba invadens.
Infection and immunity
Suresh, S., Ehrenkaufer, G., Zhang, H., Singh, U.
2016; 84 (4): 964-975
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Abstract
Entamoeba histolytica, a protozoan parasite, is an important human pathogen and a leading parasitic cause of death. The organism has two life cycle stages, trophozoites, which are responsible for tissue invasion, and cysts, which are involved in pathogen transmission.Entamoeba invadensis the model system to studyEntamoebadevelopmental biology, as high-grade regulated encystation and excystation are readily achievable. However, the lack of gene-silencing tools inE. invadenshas limited the molecular studies that can be performed. Using the endogenous RNA interference (RNAi) pathway inEntamoeba, we developed an RNAi-based trigger gene-silencing approach inE. invadens We demonstrate that a gene's coding region that has abundant antisense small RNAs (sRNAs) can trigger silencing of a gene that is fused to it. The trigger fusion leads to the generation of abundant antisense sRNAs that map to the target gene, with silencing occurring independently of trigger location at the 5' or 3' end of a gene. Gene silencing is stably maintained during development, including encystation and excystation. We have used this approach to successfully silence twoE. invadensgenes: a putative rhomboid protease gene and a SHAQKY family Myb gene. The Myb gene is upregulated during oxidative stress and development, and its downregulation led, as predicted, to decreased viability under oxidative stress and decreased cyst formation. Thus, the RNAi trigger silencing method can be used to successfully investigate the molecular functions of genes inE. invadens Dissection of the molecular basis ofEntamoebastage conversion is now possible, representing an important technical advance for the system.
View details for DOI 10.1128/IAI.01161-15
View details for PubMedID 26787723
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Technical advances in trigger-induced RNA interference gene silencing in the parasite Entamoeba histolytica
INTERNATIONAL JOURNAL FOR PARASITOLOGY
Khalil, M. I., Foda, B. M., Suresh, S., Singh, U.
2016; 46 (3): 205-212
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Abstract
Entamoeba histolytica has a robust endogenous RNA interference (RNAi) pathway. There are abundant 27 nucleotide (nt) anti-sense small RNAs (AS sRNAs) that target genes for silencing and the genome encodes many genes involved in the RNAi pathway such as Argonaute proteins. Importantly, an E. histolytica gene with numerous AS sRNAs can function as a "trigger" to induce silencing of a gene that is fused to the trigger. Thus, the amebic RNAi pathway regulates gene expression relevant to amebic biology and has additionally been harnessed as a tool for genetic manipulation. In this study we have further improved the trigger-induced gene silencing method. We demonstrate that rather than using the full-length gene, a short portion of the coding region fused to a trigger is sufficient to induce silencing; the first 537bp of the E. histolytica rhomboid gene (EhROM1) fused in-frame to the trigger was sufficient to silence EhROM1. We also demonstrated that the trigger method could silence two amebic genes concomitantly; fusion of the coding regions of EhROM1 and transcription factor, EhMyb, in-frame to a trigger gene resulted in both genes being silenced. Alternatively, two genes can be silenced sequentially: EhROM1-silenced parasites with no drug selection plasmid were transfected with trigger-EhMyb, resulting in parasites with both EhROM1 and EhMyb silenced. With all approaches tested, the trigger-mediated silencing was substantive and silencing was maintained despite loss of the G418 selectable marker. All gene silencing was associated with generation of AS sRNAs to the silenced gene. We tested the reversibility of the trigger system using inhibitors of histone modifications but found that the silencing was highly stable. This work represents a technical advance in the trigger gene silencing method in E. histolytica. Approaches that readily silence multiple genes add significantly to the genetic toolkit available to the ameba research community.
View details for DOI 10.1016/j.ijpara.2015.11.004
View details for Web of Science ID 000371951900006
View details for PubMedID 26747561
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biology: RNA interference, drug discovery, and gut microbiome.
F1000Research
Morgado, P., Manna, D., Singh, U.
2016; 5: 2578-?
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Abstract
In recent years, substantial progress has been made in understanding the molecular and cell biology of the human parasite Entamoeba histolytica, an important pathogen with significant global impact. This review outlines some recent advances in the Entamoeba field in the last five years, focusing on areas that have not recently been discussed in detail: (i) molecular mechanisms regulating parasite gene expression, (ii) new efforts at drug discovery using high-throughput drug screens, and (iii) the effect of gut microbiota on amoebiasis.
View details for PubMedID 27853522
View details for PubMedCentralID PMC5089142
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Dimethylated H3K27 Is a Repressive Epigenetic Histone Mark in the Protist Entamoeba histolytica and Is Significantly Enriched in Genes Silenced via the RNAi Pathway
JOURNAL OF BIOLOGICAL CHEMISTRY
Foda, B. M., Singh, U.
2015; 290 (34): 21114-21130
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View details for DOI 10.1074/jbc.M115.647263
View details for Web of Science ID 000360011800043
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High Throughput Sequencing of Entamoeba 27nt Small RNA Population Reveals Role in Permanent Gene Silencing But No Effect on Regulating Gene Expression Changes during Stage Conversion, Oxidative, or Heat Shock Stress
PLOS ONE
Zhang, H., Ehrenkaufer, G. M., Manna, D., Hall, N., Singh, U.
2015; 10 (8)
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View details for DOI 10.1371/journal.pone.0134481
View details for Web of Science ID 000359062300039
View details for PubMedID 26248204
The Andrews Lab
Our laboratory aims to develop innovative approaches to the control of infectious diseases in resource-limited settings. Drawing upon the fields of epidemiology, microbiology and engineering, we strive to find solutions to extend the technologies that underlie diagnosis and treatment of infectious diseases to "last-mile" communities.
Publications
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Serial QuantiFERON testing and tuberculosis disease risk among young children: an observational cohort study.
The Lancet. Respiratory medicine
Andrews, J. R., Nemes, E., Tameris, M., Landry, B. S., Mahomed, H., McClain, J. B., Fletcher, H. A., Hanekom, W. A., Wood, R., McShane, H., Scriba, T. J., Hatherill, M.
2017
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Abstract
The value of quantitative interferon-γ release assay results for predicting progression from Mycobacterium tuberculosis infection to active disease is unknown. We aimed to investigate the relation between QuantiFERON-TB Gold In-Tube (QFT) conversion interferon-γ values and risk of subsequent active tuberculosis disease and of QFT reversion.We analysed data from a reported vaccine efficacy trial of the tuberculosis vaccine MVA85A in South Africa. QFT negative, HIV uninfected young children aged 18-24 weeks were enrolled. We stratified participants by quantitative QFT result (interferon-γ <0·35 IU/mL, 0·35-4·00 IU/mL, and >4·00 IU/mL) at the intermediate study visit (day 336) and determined risk of progression to active tuberculosis disease over the subsequent 6-24 months. No QFT differences were observed between placebo and MVA85A groups at day 336 or end of study; therefore, both groups were included in analyses. Study clinicians were not masked to QFT values, but strict case definitions were used that excluded QFT results. We used generalised additive models to evaluate the quantitative relation between day 336 QFT value and subsequent disease risk, and we compared disease rates between QFT strata using a two-sample Poisson test.Among 2512 young children with QFT tests done at day 336, 172 (7%) were positive; 87 (7%) of 1267 in placebo group and 85 (7%) of 1245 in the MVA85A group (p=1·00). Compared with QFT non-converters (tuberculosis disease incidence 0·7 per 100 person-years [95% CI 0·4-1·1]), children with QFT conversion at interferon-γ values between 0·35-4·00 IU/mL did not have significantly increased risk of disease (2·5 per 100 person-years [95% CI 0·4-9·4]; incidence rate ratio (IRR) 3·7 (95% CI 0·4-15·8; p=0·23). However, QFT conversion at interferon-γ values higher than 4·00 IU/mL was associated with substantially increased disease incidence (28·0 per 100 person-years [95% CI 14·9-45·7]) compared with non-converters (IRR 42·5 [95% CI 17·2-99·7]; p<0·0001), and compared with children with interferon-γ values between 0·35-4·00 IU/mL (IRR 11·4 [95% CI 2·4-107·2]; p=0·00047). Among 91 QFT converters who were given a repeat test, 53 (58%) reverted from positive to negative. QFT reversion risk was inversely associated with interferon-γ value at QFT conversion and was highest with interferon-γ values less than 4·00 IU/mL (47 [77%] of 61).In young children, tuberculosis disease risk was not significantly increased, and QFT reversion was common, following QFT conversion at interferon-γ values up to 10 times the recommended test threshold (0·35 IU/mL). By contrast, QFT conversion at very high interferon-γ values (>4·00 IU/mL) warrants intensified diagnostic and preventive intervention because of the extremely high risk of tuberculosis disease in these young children.Aeras, Wellcome Trust, and Oxford-Emergent Tuberculosis Consortium (OETC) were the funders of the MVA85A 020 Trial. National Institute of Allergy and Infectious Diseases supported this analysis.
View details for DOI 10.1016/S2213-2600(17)30060-7
View details for PubMedID 28215501
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Assessment of global guidelines for preventive chemotherapy against schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study
LANCET INFECTIOUS DISEASES
Lo, N. C., Lai, Y., Karagiannis-Voules, D., Bogoch, I. I., Coulibaly, J. T., Bendavid, E., Utzinger, J., Vounatsou, P., Andrews, J. R.
2016; 16 (9): 1065-1075
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Abstract
WHO guidelines recommend annual treatment for schistosomiasis or soil-transmitted helminthiasis when prevalence in school-aged children is at or above a threshold of 50% and 20%, respectively. Separate treatment guidelines are used for these two helminthiases, and integrated community-wide treatment is not recommended. We assessed the cost-effectiveness of changing prevalence thresholds and treatment guidelines under an integrated delivery framework.We developed a dynamic, age-structured transmission and cost-effectiveness model that simulates integrated preventive chemotherapy programmes against schistosomiasis and soil-transmitted helminthiasis. We assessed a 5-year treatment programme with praziquantel (40 mg/kg per treatment) against schistosomiasis and albendazole (400 mg per treatment) against soil-transmitted helminthiasis at 75% coverage. We defined strategies as highly cost-effective if the incremental cost-effectiveness ratio was less than the World Bank classification for a low-income country (gross domestic product of US
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Comparison of community-wide, integrated mass drug administration strategies for schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study.
The Lancet. Global health
Lo, N. C., Bogoch, I. I., Blackburn, B. G., Raso, G., N'Goran, E. K., Coulibaly, J. T., Becker, S. L., Abrams, H. B., Utzinger, J., Andrews, J. R.
2015; 3 (10): e629-38
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Abstract
More than 1·5 billion people are affected by schistosomiasis or soil-transmitted helminthiasis. WHO's recommendations for mass drug administration (MDA) against these parasitic infections emphasise treatment of school-aged children, using separate treatment guidelines for these two helminthiases groups. We aimed to evaluate the cost-effectiveness of expanding integrated MDA to the entire community in four settings in Côte d'Ivoire.We extended previously published, dynamic, age-structured models of helminthiases transmission to simulate costs and disability averted with integrated MDA (of praziquantel and albendazole) for schistosomiasis and soil-transmitted helminthiasis. We calibrated the model to data for prevalence and intensity of species-specific helminth infection from surveys undertaken in four communities in Côte d'Ivoire between March, 1997, and September, 2010. We simulated a 15-year treatment programme with 75% coverage in only school-aged children; school-aged children and preschool-aged children; adults; and the entire community. Treatment costs were estimated at US
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Integrating Social Contact and Environmental Data in Evaluating Tuberculosis Transmission in a South African Township
JOURNAL OF INFECTIOUS DISEASES
Andrews, J. R., Morrow, C., Walensky, R. P., Wood, R.
2014; 210 (4): 597-603
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Abstract
Background. Population models of tuberculosis transmission have not accounted for social contact structure and the role of the environment in which tuberculosis is transmitted.Methods. We utilized extensions to the Wells-Riley model of tuberculosis transmission, using exhaled carbon dioxide as a tracer gas, to describe transmission patterns in an endemic community. Drawing upon social interaction data and carbon dioxide measurements from a South African township, we created an age-structured model of tuberculosis transmission in households, public transit, schools and workplaces. We fit the model to local data on latent tuberculosis prevalence by age.Results. Most tuberculosis infections (84%) were estimated to occur outside of one's own household. 50% of infections among young adults (ages 15-19) occurred in schools, due to high contact rates and poor ventilation. Despite lower numbers of contacts in workplaces, assortative mixing among adults with high rates of smear-positive tuberculosis contributed to transmission in this environment. Households and public transit were important sites of transmission between age groups.Conclusions. Consistent with molecular epidemiologic estimates, a minority of tuberculosis transmission was estimated to occur within households, which may limit the impact of contact investigations. Further work is needed to investigate the role of schools in tuberculosis transmission.
View details for DOI 10.1093/infdis/jiu138
View details for Web of Science ID 000340243500013
View details for PubMedID 24610874
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Evaluation of an Electricity-free, Culture-based Approach for Detecting Typhoidal Salmonella Bacteremia during Enteric Fever in a High Burden, Resource-limited Setting
PLOS NEGLECTED TROPICAL DISEASES
Andrews, J. R., Prajapati, K. G., Eypper, E., Shrestha, P., Shakya, M., Pathak, K. R., Joshi, N., Tiwari, P., Risal, M., Koirala, S., Karkey, A., Dongol, S., Wen, S., Smith, A. B., Maru, D., Basnyat, B., Baker, S., Farrar, J., Ryan, E. T., Hohmann, E., Arjyal, A.
2013; 7 (6)
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Abstract
In many rural areas at risk for enteric fever, there are few data on Salmonella enterica serotypes Typhi (S. Typhi) and Paratyphi (S. Paratyphi) incidence, due to limited laboratory capacity for microbiologic culture. Here, we describe an approach that permits recovery of the causative agents of enteric fever in such settings. This approach involves the use of an electricity-free incubator based upon use of phase-change materials. We compared this against conventional blood culture for detection of typhoidal Salmonella.Three hundred and four patients with undifferentiated fever attending the outpatient and emergency departments of a public hospital in the Kathmandu Valley of Nepal were recruited. Conventional blood culture was compared against an electricity-free culture approach. Blood from 66 (21.7%) patients tested positive for a Gram-negative bacterium by at least one of the two methods. Sixty-five (21.4%) patients tested blood culture positive for S. Typhi (30; 9.9%) or S. Paratyphi A (35; 11.5%). From the 65 individuals with culture-confirmed enteric fever, 55 (84.6%) were identified by the conventional blood culture and 60 (92.3%) were identified by the experimental method. Median time-to-positivity was 2 days for both procedures. The experimental approach was falsely positive due to probable skin contaminants in 2 of 239 individuals (0.8%). The percentages of positive and negative agreement for diagnosis of enteric fever were 90.9% (95% CI: 80.0%-97.0%) and 96.0% (92.7%-98.1%), respectively. After initial incubation, Salmonella isolates could be readily recovered from blood culture bottles maintained at room temperature for six months.A simple culture approach based upon a phase-change incubator can be used to isolate agents of enteric fever. This approach could be used as a surveillance tool to assess incidence and drug resistance of the etiologic agents of enteric fever in settings without reliable local access to electricity or local diagnostic microbiology laboratories.
View details for DOI 10.1371/journal.pntd.0002292
View details for Web of Science ID 000321201300043
View details for PubMedID 23853696
The Bollyky Lab
Our lab studies how immune responses are regulated within injured and infected tissues. We work at the intersection of immunology, structural biology, bioengineering, and microbiology. Our goals are to understand the factors that drive chronic inflammation and to develop novel therapeutics to promote wound healing and immune tolerance.
Publications
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Hyaluronan synthesis is necessary for autoreactive T-cell trafficking, activation, and Th1 polarization.
Proceedings of the National Academy of Sciences of the United States of America
Kuipers, H. F., Rieck, M., Gurevich, I., Nagy, N., Butte, M. J., Negrin, R. S., Wight, T. N., Steinman, L., Bollyky, P. L.
2016; 113 (5): 1339-1344
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Abstract
The extracellular matrix polysaccharide hyaluronan (HA) accumulates at sites of autoimmune inflammation, including white matter lesions in multiple sclerosis (MS), but its functional importance in pathogenesis is unclear. We have evaluated the impact of 4-methylumbelliferone (4-MU), an oral inhibitor of HA synthesis, on disease progression in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Treatment with 4-MU decreases the incidence of EAE, delays its onset, and reduces the severity of established disease. 4-MU inhibits the activation of autoreactive T cells and prevents their polarization toward a Th1 phenotype. Instead, 4-MU promotes polarization toward a Th2 phenotpye and induction of Foxp3(+) regulatory T cells. Further, 4-MU hastens trafficking of T cells through secondary lymphoid organs, impairs the infiltration of T cells into the CNS parenchyma, and limits astrogliosis. Together, these data suggest that HA synthesis is necessary for disease progression in EAE and that treatment with 4-MU may be a potential therapeutic strategy in CNS autoimmunity. Considering that 4-MU is already a therapeutic, called hymecromone, that is approved to treat biliary spasm in humans, we propose that it could be repurposed to treat MS.
View details for DOI 10.1073/pnas.1525086113
View details for PubMedID 26787861
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Filamentous Bacteriophage Promote Biofilm Assembly and Function
CELL HOST & MICROBE
Secor, P. R., Sweere, J. M., Michaels, L. A., Malkovskiy, A. V., Lazzareschi, D., Katznelson, E., Rajadas, J., Birnbaum, M. E., Arrigoni, A., Braun, K. R., Evanko, S. P., Stevens, D. A., Kaminsky, W., Singh, P. K., Parks, W. C., Bollyky, P. L.
2015; 18 (5): 549-559
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Abstract
Biofilms-communities of bacteria encased in a polymer-rich matrix-confer bacteria with the ability to persist in pathologic host contexts, such as the cystic fibrosis (CF) airways. How bacteria assemble polymers into biofilms is largely unknown. We find that the extracellular matrix produced by Pseudomonas aeruginosa self-assembles into a liquid crystal through entropic interactions between polymers and filamentous Pf bacteriophages, which are long, negatively charged filaments. This liquid crystalline structure enhances biofilm function by increasing adhesion and tolerance to desiccation and antibiotics. Pf bacteriophages are prevalent among P. aeruginosa clinical isolates and were detected in CF sputum. The addition of Pf bacteriophage to sputum polymers or serum was sufficient to drive their rapid assembly into viscous liquid crystals. Fd, a related bacteriophage of Escherichia coli, has similar biofilm-building capabilities. Targeting filamentous bacteriophage or the liquid crystalline organization of the biofilm matrix may represent antibacterial strategies.
View details for DOI 10.1016/j.chom.2015.10.013
View details for Web of Science ID 000365113100008
View details for PubMedID 26567508
View details for PubMedCentralID PMC4653043
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Inhibition of hyaluronan synthesis restores immune tolerance during autoimmune insulitis.
The Journal of clinical investigation
Nagy, N., Kaber, G., Johnson, P. Y., Gebe, J. A., Preisinger, A., Falk, B. A., Sunkari, V. G., Gooden, M. D., Vernon, R. B., Bogdani, M., Kuipers, H. F., Day, A. J., Campbell, D. J., Wight, T. N., Bollyky, P. L.
2015
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Abstract
We recently reported that abundant deposits of the extracellular matrix polysaccharide hyaluronan (HA) are characteristic of autoimmune insulitis in patients with type 1 diabetes (T1D), but the relevance of these deposits to disease was unclear. Here, we have demonstrated that HA is critical for the pathogenesis of autoimmune diabetes. Using the DO11.10xRIPmOVA mouse model of T1D, we determined that HA deposits are temporally and anatomically associated with the development of insulitis. Moreover, treatment with an inhibitor of HA synthesis, 4-methylumbelliferone (4-MU), halted progression to diabetes even after the onset of insulitis. Similar effects were seen in the NOD mouse model, and in these mice, 1 week of treatment was sufficient to prevent subsequent diabetes. 4-MU reduced HA accumulation, constrained effector T cells to nondestructive insulitis, and increased numbers of intraislet FOXP3+ Tregs. Consistent with the observed effects of 4-MU treatment, Treg differentiation was inhibited by HA and anti-CD44 antibodies and rescued by 4-MU in an ERK1/2-dependent manner. These data may explain how peripheral immune tolerance is impaired in tissues under autoimmune attack, including islets in T1D. We propose that 4-MU, already an approved drug used to treat biliary spasm, could be repurposed to prevent, and possibly treat, T1D in at-risk individuals.
View details for DOI 10.1172/JCI79271
View details for PubMedID 26368307
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ECM components guide IL-10 producing regulatory T-cell (TR1) induction from effector memory T-cell precursors
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Bollyky, P. L., Wu, R. P., Falk, B. A., Lord, J. D., Long, S. A., Preisinger, A., Teng, B., Holt, G. E., Standifer, N. E., Braun, K. R., Xie, C. F., Samuels, P. L., Vernon, R. B., Gebe, J. A., Wight, T. N., Nepom, G. T.
2011; 108 (19): 7938-7943
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Abstract
We describe a role for ECM as a biosensor for inflammatory microenvironments that plays a critical role in peripheral immune tolerance. We show that hyaluronan (HA) promotes induction of Foxp3- IL-10-producing regulatory T cells (TR1) from conventional T-cell precursors in both murine and human systems. This is, to our knowledge, the first description of an ECM component inducing regulatory T cells. Intact HA, characteristic of healing tissues, promotes induction of TR1 capable of abrogating disease in an IL-10-dependent mouse colitis model whereas fragmentary HA, typical of inflamed tissues, does not, indicating a decisive role for tissue integrity in this system. The TR1 precursor cells in this system are CD4(+)CD62L(-)FoxP3(-), suggesting that effector memory cells assume a regulatory phenotype when they encounter their cognate antigen in the context of intact HA. Matrix integrity cues might thereby play a central role in maintaining peripheral tolerance. This TR1 induction is mediated by CD44 cross-linking and signaling through p38 and ERK1/2. This induction is suppressed, also in a CD44-dependent manner, by osteopontin, a component of chronically inflamed ECM, indicating that CD44 signaling serves as a nexus for fate decisions regarding TR1 induction. Finally, we demonstrate that TR1 induction signals can be recapitulated using synthetic matrices. These results reveal important roles for the matrix microenvironment in immune regulation and suggest unique strategies for immunomodulation.
View details for DOI 10.1073/pnas.1017360108
View details for Web of Science ID 000290439500058
View details for PubMedID 21518860
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Hyaluronan: A Master Switch Between Vascular Homeostasis and Inflammation.
Circulation research
Grandoch, M., Bollyky, P. L., Fischer, J. W.
2018; 122 (10): 1341–43
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View details for DOI 10.1161/CIRCRESAHA.118.312522
View details for PubMedID 29748364
The Relman Lab
David Relman's investigative program falls within the general themes of host-pathogen interactions and human microbial ecology, and is divided into two research areas:
- Ecology of microbial communities indigenous to humans and other mammalian hosts
- Genome-wide host response patterns in systemic infectious disease
Publications
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A spatial gradient of bacterial diversity in the human oral cavity shaped by salivary flow.
Nature communications
Proctor, D. M., Fukuyama, J. A., Loomer, P. M., Armitage, G. C., Lee, S. A., Davis, N. M., Ryder, M. I., Holmes, S. P., Relman, D. A.
2018; 9 (1): 681
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Abstract
Spatial and temporal patterns in microbial communities provide insights into the forces that shape them, their functions and roles in health and disease. Here, we used spatial and ecological statistics to analyze the role that saliva plays in structuring bacterial communities of the human mouth using >9000 dental and mucosal samples. We show that regardless of tissue type (teeth, alveolar mucosa, keratinized gingiva, or buccal mucosa), surface-associated bacterial communities vary along an ecological gradient from the front to the back of the mouth, and that on exposed tooth surfaces, the gradient is pronounced on lingual compared to buccal surfaces. Furthermore, our data suggest that this gradient is attenuated in individuals with low salivary flow due to Sjögren's syndrome. Taken together, our findings imply that salivary flow influences the spatial organization of microbial communities and that biogeographical patterns may be useful for understanding host physiological processes and for predicting disease.
View details for DOI 10.1038/s41467-018-02900-1
View details for PubMedID 29445174
View details for PubMedCentralID PMC5813034
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Clostridium difficile, Aging, and the Gut: Can Microbiome Rejuvenation Keep Us Young and Healthy?
The Journal of infectious diseases
Fischer, N., Relman, D. A.
2018; 217 (2): 174–76
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View details for DOI 10.1093/infdis/jix417
View details for PubMedID 28968708
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Enterotypes in the landscape of gut microbial community composition.
Nature microbiology
Costea, P. I., Hildebrand, F., Arumugam, M., Bäckhed, F., Blaser, M. J., Bushman, F. D., de Vos, W. M., Ehrlich, S. D., Fraser, C. M., Hattori, M., Huttenhower, C., Jeffery, I. B., Knights, D., Lewis, J. D., Ley, R. E., Ochman, H., O'Toole, P. W., Quince, C., Relman, D. A., Shanahan, F., Sunagawa, S., Wang, J., Weinstock, G. M., Wu, G. D., Zeller, G., Zhao, L., Raes, J., Knight, R., Bork, P.
2018; 3 (1): 8–16
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Abstract
Population stratification is a useful approach for a better understanding of complex biological problems in human health and wellbeing. The proposal that such stratification applies to the human gut microbiome, in the form of distinct community composition types termed enterotypes, has been met with both excitement and controversy. In view of accumulated data and re-analyses since the original work, we revisit the concept of enterotypes, discuss different methods of dividing up the landscape of possible microbiome configurations, and put these concepts into functional, ecological and medical contexts. As enterotypes are of use in describing the gut microbial community landscape and may become relevant in clinical practice, we aim to reconcile differing views and encourage a balanced application of the concept.
View details for DOI 10.1038/s41564-017-0072-8
View details for PubMedID 29255284
View details for PubMedCentralID PMC5832044
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Role of priority effects in the early-life assembly of the gut microbiota.
Nature reviews. Gastroenterology & hepatology
Sprockett, D., Fukami, T., Relman, D. A.
2018; 15 (4): 197–205
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Abstract
Understanding how microbial communities develop is essential for predicting and directing their future states. Ecological theory suggests that community development is often influenced by priority effects, in which the order and timing of species arrival determine how species affect one another. Priority effects can have long-lasting consequences, particularly if species arrival history varies during the early stage of community development, but their importance to the human gut microbiota and host health remains largely unknown. Here, we explore how priority effects might influence microbial communities in the gastrointestinal tract during early childhood and how the strength of priority effects can be estimated from the composition of the microbial species pool. We also discuss factors that alter microbial transmission, such as delivery mode, diet and parenting behaviours such as breastfeeding, which can influence the likelihood of priority effects. An improved knowledge of priority effects has the potential to inform microorganism-based therapies, such as prebiotics and probiotics, which are aimed at guiding the microbiota towards a healthy state.
View details for DOI 10.1038/nrgastro.2017.173
View details for PubMedID 29362469
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Rethinking biosecurity
ISSUES IN SCIENCE AND TECHNOLOGY
Relman, D. A.
2017; 33 (2): 13–14
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View details for Web of Science ID 000391903400009
The Wang Lab
Taia Wang’s laboratory studies mechanisms underlying the heterogeneity in human immune function during vaccination and viral infection. We are particularly interested in antibody-mediated immunity and determinants of susceptibility to antibody-mediated diseases.
Publications
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Immunity by Design.
Cell host & microbe
Wang, T. T.
2018; 23 (4): 430–31
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Abstract
One outcome of the many advances in basic sciences that have been made over the last decades is the prospect of rational vaccine design. A recent publication by Du et al. (2018) describes a screening method for selection of live-attenuated viral vaccine platforms with enhanced immune-stimulatory properties.
View details for DOI 10.1016/j.chom.2018.03.017
View details for PubMedID 29649438
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IgG antibodies to dengue enhanced for FcγRIIIA binding determine disease severity.
Science (New York, N.Y.)
Wang, T. T., Sewatanon, J., Memoli, M. J., Wrammert, J., Bournazos, S., Bhaumik, S. K., Pinsky, B. A., Chokephaibulkit, K., Onlamoon, N., Pattanapanyasat, K., Taubenberger, J. K., Ahmed, R., Ravetch, J. V.
2017; 355 (6323): 395–98
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Abstract
Dengue virus (DENV) infection in the presence of reactive, non-neutralizing immunoglobulin G (IgG) (RNNIg) is the greatest risk factor for dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). Progression to DHF/DSS is attributed to antibody-dependent enhancement (ADE); however, because only a fraction of infections occurring in the presence of RNNIg advance to DHF/DSS, the presence of RNNIg alone cannot account for disease severity. We discovered that DHF/DSS patients respond to infection by producing IgGs with enhanced affinity for the activating Fc receptor FcγRIIIA due to afucosylated Fc glycans and IgG1 subclass. RNNIg enriched for afucosylated IgG1 triggered platelet reduction in vivo and was a significant risk factor for thrombocytopenia. Thus, therapeutics and vaccines restricting production of afucosylated, IgG1 RNNIg during infection may prevent ADE of DENV disease.
View details for DOI 10.1126/science.aai8128
View details for PubMedID 28126818
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Increasing the breadth and potency of response to the seasonal influenza virus vaccine by immune complex immunization.
Proceedings of the National Academy of Sciences of the United States of America
Maamary, J., Wang, T. T., Tan, G. S., Palese, P., Ravetch, J. V.
2017
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Abstract
The main barrier to reduction of morbidity caused by influenza is the absence of a vaccine that elicits broad protection against different virus strains. Studies in preclinical models of influenza virus infections have shown that antibodies alone are sufficient to provide broad protection against divergent virus strains in vivo. Here, we address the challenge of identifying an immunogen that can elicit potent, broadly protective, antiinfluenza antibodies by demonstrating that immune complexes composed of sialylated antihemagglutinin antibodies and seasonal inactivated flu vaccine (TIV) can elicit broadly protective antihemagglutinin antibodies. Further, we found that an Fc-modified, bispecific monoclonal antibody against conserved epitopes of the hemagglutinin can be combined with TIV to elicit broad protection, thus setting the stage for a universal influenza virus vaccine.
View details for DOI 10.1073/pnas.1707950114
View details for PubMedID 28874545
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Signaling by Antibodies: Recent Progress
Annual Review of Immunology
Bournazos, S., Wang, T. T., Dahan, R., Maamary, J., Ravetch, J. V.
2017; 35 (April 26): 285-311
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View details for DOI 10.1146/annurev-immunol-051116-052433
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The Role and Function of Fcγ Receptors on Myeloid Cells.
Microbiology spectrum
Bournazos, S., Wang, T. T., Ravetch, J. V.
2016; 4 (6)
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Abstract
A key determinant for the survival of organisms is their capacity to recognize and respond efficiently to foreign antigens. This is largely accomplished by the orchestrated activity of the innate and adaptive branches of the immune system. Antibodies are specifically generated in response to foreign antigens, facilitating thereby the specific recognition of antigens of almost infinite diversity. Receptors specific for the Fc domain of antibodies, Fc receptors, are expressed on the surface of the various myeloid leukocyte populations and mediate the binding and recognition of antibodies by innate leukocytes. By directly linking the innate and the adaptive components of immunity, Fc receptors play a central role in host defense and the maintenance of tissue homeostasis through the induction of diverse proinflammatory, anti-inflammatory, and immunomodulatory processes that are initiated upon engagement by the Fc domain. In this chapter, we discuss the mechanisms that regulate Fc domain binding to the various types of Fc receptors and provide an overview of the astonishing diversity of effector functions that are mediated through Fc-FcR interactions on myeloid cells. Lastly, we discuss the impact of FcR-mediated interactions in the context of IgG-mediated inflammation, autoimmunity, susceptibility to infection, and responsiveness to antibody-based therapeutics.
View details for DOI 10.1128/microbiolspec.MCHD-0045-2016
View details for PubMedID 28087938
Jagannathan Lab
The goals of this laboratory are to further our understanding of the correlates and mechanisms of clinical immunity to malaria through field-based studies, and to better understand the immunologic consequences of malaria control interventions.
These studies bridge immune profiling techniques including multiparameter flow cytometry, transcriptomics, epigenetics, and multiplex antibody profiling to epidemiologic studies of antimalarial immunity in children.
Publications
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Vδ2+ T cell response to malaria correlates with protection from infection but is attenuated with repeated exposure.
Scientific reports
Jagannathan, P., Lutwama, F., Boyle, M. J., Nankya, F., Farrington, L. A., McIntyre, T. I., Bowen, K., Naluwu, K., Nalubega, M., Musinguzi, K., Sikyomu, E., Budker, R., Katureebe, A., Rek, J., Greenhouse, B., Dorsey, G., Kamya, M. R., Feeney, M. E.
2017; 7 (1): 11487
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Abstract
Vδ2(+) γδ T cells are semi-innate T cells that expand markedly following P. falciparum (Pf) infection in naïve adults, but are lost and become dysfunctional among children repeatedly exposed to malaria. The role of these cells in mediating clinical immunity (i.e. protection against symptoms) to malaria remains unclear. We measured Vδ2(+) T cell absolute counts at acute and convalescent malaria timepoints (n = 43), and Vδ2(+) counts, cellular phenotype, and cytokine production following in vitro stimulation at asymptomatic visits (n = 377), among children aged 6 months to 10 years living in Uganda. Increasing age was associated with diminished in vivo expansion following malaria, and lower Vδ2 absolute counts overall, among children living in a high transmission setting. Microscopic parasitemia and expression of the immunoregulatory markers Tim-3 and CD57 were associated with diminished Vδ2(+) T cell pro-inflammatory cytokine production. Higher Vδ2 pro-inflammatory cytokine production was associated with protection from subsequent Pf infection, but also with an increased odds of symptoms once infected. Vδ2(+) T cells may play a role in preventing malaria infection in children living in endemic settings; progressive loss and dysfunction of these cells may represent a disease tolerance mechanism that contributes to the development of clinical immunity to malaria.
View details for DOI 10.1038/s41598-017-10624-3
View details for PubMedID 28904345
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Effective Antimalarial Chemoprevention in Childhood Enhances the Quality of CD4(+) T Cells and Limits Their Production of Immunoregulatory Interleukin 10
JOURNAL OF INFECTIOUS DISEASES
Jagannathan, P., Bowen, K., Nankya, F., McIntyre, T. I., Auma, A., Wamala, S., Sikyomu, E., Naluwu, K., Nalubega, M., Boyle, M. J., Farrington, L. A., Bigira, V., Kapisi, J., Aweeka, F., Greenhouse, B., Kamya, M., Dorsey, G., Feeney, M. E.
2016; 214 (2): 329-338
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Abstract
Experimental inoculation of viable Plasmodium falciparum sporozoites administered with chemoprevention targeting blood-stage parasites results in protective immunity. It is unclear whether chemoprevention similarly enhances immunity following natural exposure to malaria.We assessed P. falciparum-specific T-cell responses among Ugandan children who were randomly assigned to receive monthly dihydroartemisinin-piperaquine (DP; n = 87) or no chemoprevention (n = 90) from 6 to 24 months of age, with pharmacologic assessments for adherence, and then clinically followed for an additional year.During the intervention, monthly DP reduced malaria episodes by 55% overall (P < .001) and by 97% among children who were highly adherent to DP (P < .001). In the year after the cessation of chemoprevention, children who were highly adherent to DP had a 55% reduction in malaria incidence as compared to children given no chemoprevention (P = .004). Children randomly assigned to receive DP had higher frequencies of blood-stage specific CD4(+) T cells coproducing interleukin-2 and tumor necrosis factor α (P = .003), which were associated with protection from subsequent clinical malaria and parasitemia, and fewer blood-stage specific CD4(+) T cells coproducing interleukin-10 and interferon γ (P = .001), which were associated with increased risk of malaria.In this setting, effective antimalarial chemoprevention fostered the development of CD4(+) T cells that coproduced interleukin 2 and tumor necrosis factor α and were associated with prospective protection, while limiting CD4(+) T-cell production of the immunoregulatory cytokine IL-10.
View details for DOI 10.1093/infdis/jiw147
View details for Web of Science ID 000379822900021
View details for PubMedID 27067196
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Dihydroartemisinin-Piperaquine for the Prevention of Malaria in Pregnancy
NEW ENGLAND JOURNAL OF MEDICINE
Kakuru, A., Jagannathan, P., Muhindo, M. K., Natureeba, P., Awori, P., Nakalembe, M., Opira, B., Olwoch, P., Ategeka, J., Nayebare, P., Clark, T. D., Feeney, M. E., Charlebois, E. D., Rizzuto, G., Muehlenbachs, A., Havlir, D. V., Kamya, M. R., Dorsey, G.
2016; 374 (10): 928-939
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Abstract
Intermittent treatment with sulfadoxine-pyrimethamine is widely recommended for the prevention of malaria in pregnant women in Africa. However, with the spread of resistance to sulfadoxine-pyrimethamine, new interventions are needed.We conducted a double-blind, randomized, controlled trial involving 300 human immunodeficiency virus (HIV)-uninfected pregnant adolescents or women in Uganda, where sulfadoxine-pyrimethamine resistance is widespread. We randomly assigned participants to a sulfadoxine-pyrimethamine regimen (106 participants), a three-dose dihydroartemisinin-piperaquine regimen (94 participants), or a monthly dihydroartemisinin-piperaquine regimen (100 participants). The primary outcome was the prevalence of histopathologically confirmed placental malaria.The prevalence of histopathologically confirmed placental malaria was significantly higher in the sulfadoxine-pyrimethamine group (50.0%) than in the three-dose dihydroartemisinin-piperaquine group (34.1%, P=0.03) or the monthly dihydroartemisinin-piperaquine group (27.1%, P=0.001). The prevalence of a composite adverse birth outcome was lower in the monthly dihydroartemisinin-piperaquine group (9.2%) than in the sulfadoxine-pyrimethamine group (18.6%, P=0.05) or the three-dose dihydroartemisinin-piperaquine group (21.3%, P=0.02). During pregnancy, the incidence of symptomatic malaria was significantly higher in the sulfadoxine-pyrimethamine group (41 episodes over 43.0 person-years at risk) than in the three-dose dihydroartemisinin-piperaquine group (12 episodes over 38.2 person-years at risk, P=0.001) or the monthly dihydroartemisinin-piperaquine group (0 episodes over 42.3 person-years at risk, P<0.001), as was the prevalence of parasitemia (40.5% in the sulfadoxine-pyrimethamine group vs. 16.6% in the three-dose dihydroartemisinin-piperaquine group [P<0.001] and 5.2% in the monthly dihydroartemisinin-piperaquine group [P<0.001]). In each treatment group, the risk of vomiting after administration of any dose of the study agents was less than 0.4%, and there were no significant differences among the groups in the risk of adverse events.The burden of malaria in pregnancy was significantly lower among adolescent girls or women who received intermittent preventive treatment with dihydroartemisinin-piperaquine than among those who received sulfadoxine-pyrimethamine, and monthly treatment with dihydroartemisinin-piperaquine was superior to three-dose dihydroartemisinin-piperaquine with regard to several outcomes. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ClinicalTrials.gov number, NCT02163447.).
View details for DOI 10.1056/NEJMoa1509150
View details for Web of Science ID 000371660000006
View details for PubMedID 26962728
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Loss and dysfunction of Vd2? ?d T cells are associated with clinical tolerance to malaria.
Science translational medicine
Jagannathan, P., Kim, C. C., Greenhouse, B., Nankya, F., Bowen, K., Eccles-James, I., Muhindo, M. K., Arinaitwe, E., Tappero, J. W., Kamya, M. R., Dorsey, G., Feeney, M. E.
2014; 6 (251): 251ra117-?
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Abstract
Although clinical immunity to malaria eventually develops among children living in endemic settings, the underlying immunologic mechanisms are not known. The Vδ2(+) subset of γδ T cells have intrinsic reactivity to malaria antigens, can mediate killing of Plasmodium falciparum merozoites, and expand markedly in vivo after malaria infection in previously naïve hosts, but their role in mediating immunity in children repeatedly exposed to malaria is unclear. We evaluated γδ T cell responses to malaria among 4-year-old children enrolled in a longitudinal study in Uganda. We found that repeated malaria was associated with reduced percentages of Vδ2(+) γδ T cells in peripheral blood, decreased proliferation and cytokine production in response to malaria antigens, and increased expression of immunoregulatory genes. Further, loss and dysfunction of proinflammatory Vδ2(+) γδ T cells were associated with a reduced likelihood of symptoms upon subsequent P. falciparum infection. Together, these results suggest that repeated malaria infection during childhood results in progressive loss and dysfunction of Vδ2(+) γδ T cells that may facilitate immunological tolerance of the parasite.
View details for DOI 10.1126/scitranslmed.3009793
View details for PubMedID 25163477
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IFN gamma/IL-10 Co-producing Cells Dominate the CD4 Response to Malaria in Highly Exposed Children
PLOS PATHOGENS
Jagannathan, P., Eccles-James, I., Bowen, K., Nankya, F., Auma, A., Wamala, S., Ebusu, C., Muhindo, M. K., Arinaitwe, E., Briggs, J., Greenhouse, B., Tappero, J. W., Kamya, M. R., Dorsey, G., Feeney, M. E.
2014; 10 (1)
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Abstract
Although evidence suggests that T cells are critical for immunity to malaria, reliable T cell correlates of exposure to and protection from malaria among children living in endemic areas are lacking. We used multiparameter flow cytometry to perform a detailed functional characterization of malaria-specific T cells in 78 four-year-old children enrolled in a longitudinal cohort study in Tororo, Uganda, a highly malaria-endemic region. More than 1800 episodes of malaria were observed in this cohort, with no cases of severe malaria. We quantified production of IFNγ, TNFα, and IL-10 (alone or in combination) by malaria-specific T cells, and analyzed the relationship of this response to past and future malaria incidence. CD4(+) T cell responses were measurable in nearly all children, with the majority of children having CD4(+) T cells producing both IFNγ and IL-10 in response to malaria-infected red blood cells. Frequencies of IFNγ/IL10 co-producing CD4(+) T cells, which express the Th1 transcription factor T-bet, were significantly higher in children with ≥2 prior episodes/year compared to children with <2 episodes/year (P<0.001) and inversely correlated with duration since malaria (Rho = -0.39, P<0.001). Notably, frequencies of IFNγ/IL10 co-producing cells were not associated with protection from future malaria after controlling for prior malaria incidence. In contrast, children with <2 prior episodes/year were significantly more likely to exhibit antigen-specific production of TNFα without IL-10 (P = 0.003). While TNFα-producing CD4(+) T cells were not independently associated with future protection, the absence of cells producing this inflammatory cytokine was associated with the phenotype of asymptomatic infection. Together these data indicate that the functional phenotype of the malaria-specific T cell response is heavily influenced by malaria exposure intensity, with IFNγ/IL10 co-producing CD4(+) T cells dominating this response among highly exposed children. These CD4(+) T cells may play important modulatory roles in the development of antimalarial immunity.
View details for DOI 10.1371/journal.ppat.1003864
View details for Web of Science ID 000332640900031
View details for PubMedID 24415936