Download 11.1 Defense Against Infectious Disease

11.1 Defense Against Infectious
Disease
Process of blood clotting
• When small vessels burst, blood escapes into your
surrounding tissues (often these are close to your skin
so we need to clot quickly in order to prevent pathogens
from entering your body)
• Review of items circulating in blood:
– Red blood cells
– White blood cells
– Plasma
– Platelets
1. Cells of damaged blood vessels release chemicals
which stimulate platelets to adhere to damaged
area
2. Other platelets begin to adhere to those platelets
3. Damaged tissue and platelets release chemicals
called clotting factors which convert prothrombin
to thrombin (thrombin is an enzyme that converts
fibrinogen to fibrin)
4. The fibrin forms a mesh-like network that stabilizes
the plug of platelets
5. More and more cellular debris becomes trapped in
the fibrin and soon you have a stable clot
Fundamental Principles of Immunity
1. Challenge and Response
• The immune system must be challenged by an
antigen during the first infection in order to
develop an immunity; all the cellular events
(macrophage, helper-T, B cells) are part of the
response which leads to immunity
2. Clonal Selection
• The identification of the necessary B cells that can
help with a specific pathogen and the mitosis that
is required to build up numbers
3. Memory Cells
• The cells that provide long-term immunity; you
must experience a pathogen (antigen) once in
order to produce these cells
Active vs. Passive Immunity
• Active Immunity – being exposed to a pathogen and
having the full immune response; memory cells will
be created (this includes vaccinations)
• Passive Immunity – organism acquires antibodies
produced in another organism; no memory cells
created
Ex: transfer from mom to fetus, transfer from early
breast milk (colostrum) to baby, injections of antiserum
(snake/spider bites)
Polyclonal and Monoclonal antibodies
• Polyclonal – most primary immune responses b/c
the pathogen will be recognized as many antigens
and will trigger the clonal selection of multiple B
cells (capsid of virus made up of more than one
type of protein)
• Monoclonal – a way to have only one type of
antibody but lots of them; these are useful for:
– Diagnosis: Pregnancy testing with HCG
– Treatment: to identify and destroy cancer cells (cancer
cells produce cancer-specific antigens on cell
membrane)
How to make Monoclonal Antibodies
1. Inject antigen into lab animal (must be specific
with antigen selection in order to make specific
antibody)
2. Animal goes through primary immune response
3. The spleen of the lab animal is harvested to get to
blood cells specifically the newly cloned B cells
4. B cells are removed and fused with cancerous
myeloma cells to form hybridoma cells
5. Hybridoma cells grown in separate cultures
6. Each container tested for needed antibody using
screening test called ELISA (enzyme-linked
immunosorbet assay)
7. ELISA test identifies which container has the
needed B cells (which produce desired antibody)
8. These cells can be cultured for a long period of
time and can continue to make needed B
cells/antibody
Homework:
• Answer the following questions in your notes.
Answers can be found in green book in 11.1
– Graph the antibody concentration vs. time for your
body’s primary and secondary immune responses
– Explain the principle of vaccination
– 3 benefits of vaccinations
– 3 dangers of vaccinations