Effects of hypothermia on immunoreaction after stroke. A. In vitro assay for T cell proliferation after stroke. Splenocytes were prepared 72 h after stroke from 4 groups of animals, including naive, sham surgery, normothermic and hypothermic animals. The cultured splenocytes were stimulated with 0 μg/ml, 1 μg/ml, 2.5 μg/ml and 5 μg/ml Concanavalin A. The cells were incubated for 66 h at 37°C and 5% CO2. [3H]-Thymidine was added to the culture and incubated for 18 h. Cells were harvested onto a glass fiber filter. The amount of radioactivity that integrated into divided lymphocytes was measured by a beta-plate scintillation reader. Results are expressed as counts per minute (cpm). *, ** vs. naive, Δ, ΔΔ vs. sham, #, # # 30°C vs. 37°C, P<0.05, 0.01, respectively, n = 5 wells/experiment, repeat 5 times. B. In vivo DTH test to measure immune response in naive rats, rats receiving sham surgery, or stroke with or without hypothermia. The antigen, ovalbumin, was injected subcutaneously at the base of the tail. Stroke was induced 14 d after immunization, and 1 d after stroke, rats were challenged intradermally with an OVA solution in the pinna of the ears. The inflamed area was measured 3 times to get the mean value at 48-72 h after the challenge. *, **, vs. naive, Δ, ΔΔ, vs. sham, #, # #, 30°C vs. 37°C, P<0.05, 0.01, respectively, n=5/group.