What Is Immunotherapy (Biological Therapy)?
Immunotherapy is a type of biological therapy that uses the body's
immune system to fight disease. The cells, antibodies, and organs of
the immune system work to protect and defend the body against foreign
invaders, such as bacteria or viruses.
Doctors and researchers have found that the immune system might also
be able to determine the difference between healthy cells and cancer
cells in the body, and eliminate the cancer cells.
Immunotherapies are designed to boost the immune system, either
directly or indirectly, by assisting in:
- Making cancer cells more recognizable by the immune system,
and therefore more susceptible to destruction by the immune
system
- Boosting the killing power of immune system cells
- Changing the way cancer cells grow, so that they act more like
healthy cells
- Stopping the process that changes a normal
cell into a cancerous cell
- Enhancing the body's ability to
repair or replace normal cells damaged or destroyed by other forms
of cancer treatment, such as chemotherapy or radiation
- Preventing cancer cells from spreading to other parts of the
body
The first reported cancer treatment using monoclonal antibodies, a
type of immunotherapy, was developed at Stanford in 1981 by Ronald
Levy, MD.
How does the immune system fight cancer?
The immune system includes different types of white blood cells -
each with a different way to fight against foreign or diseased cells,
including cancer:
-
Lymphocytes—white blood cells, including B cells, T cells,
and NK cells
-
B cells—produce antibodies that attack other cells
-
T cells—directly attack cancer cells themselves and
signal other immune system cells to defend the body
-
Natural killer cells (NK cells)—produce chemicals that
bind to and kill foreign invaders in the body
-
Monocytes—white blood cells that swallow and digest foreign
particles.
B cells, T cells, natural killer cells, and monocytes are white
blood cells in the blood and thus, circulate to every part of the
body, providing protection from cancer and other diseases. Cells
secrete two types of substances: antibodies and cytokines. Antibodies
respond to (harmful) substances that they recognize, called antigens.
Specific (helpful) antibodies match specific (foreign) antigens by
locking together. Cytokines are proteins produced by some immune
system cells and can directly attack cancer cells. Cytokines are
"messengers" that "communicate" with other cells.