Transcript a. active site is covered (toxin)

IV. The Human Body’s Immune Response
A. Terms:
1. Antigen – a foreign substance in your body
2. Antibodies – proteins that bind specifically to antigens to
inactivate them
a. cover active sites (toxin)
b. cover receptors (virus)
c. bind to and “tag”
bacteria for immune
cells to “eat”
3. Lymphocytes – class of white blood cells
a. B-cells – made in the bone marrow
-- make and secrete antibodies
b. T-cells – made in the thymus (gland in your neck)
-- two types:
T-helper – organize other white blood cells to fight
infections
T-killer – directly kill tumor cells, viral infected cells,
sometimes parasites
c. Natural Killer cells – similar to T-killer cells
d. Granulocytes – eat bacteria and parasites
e. Macrophages – “scavengers” – pick up antigens and
present them to the B or T cells. They
also “eat” tagged bacteria
f. Virgin Cell – type of B-cell that is small and
metabolically at rest…move freely in your
blood
-- you are born with millions of these
-- has thousands of identical antibodies on
the membrane
-- no two virgin cells have exactly the same
antibodies
g. Memory Cell – replica of a stimulated virgin cell
-- cells with antibodies still connected
-- make response to virus a 2nd time
much quicker. Thus, immunity
h. Plasma Cell – replica of a stimulated virgin cell
-- release attached antibodies into your
B. Sequence of Events:
1. antigen enters the body
2. macrophage “picks up” antigen and “presents” it to the
virgin cell and the T-cell.
3. Virgin cell’s antibodies bind to the antigen – this
stimulates the virgin cell to grow
4. When the virgin cell is full grow, it divides many times,
producing plasma and memory cells.
5. T-cells direct NK cells and T-killer cells to eat antigen
infected cells.
6. Antibodies released from plasma cells bind to antigen
a. active site is covered (toxin)
b. receptor is covered (virus)
c. bacteria is “tagged” for granulocytes or macrophages to eat
C. Immunity
1. The memory cells created in the above process remain
in the body forever.
2. When the virus, toxin, bacteria, or parasite invades a 2nd
time, the body can react much faster because the first 3
steps are skipped.
D. Vaccination:
1. History -- Edward Jenner -- 1796 -- English -- small pox was killing many
people around him. He noticed that milkmaids (women who milked
cows) were not getting this disease even though they were exposed.
These women would often get "sores" on their hands which was a result
of contracting the cowpox disease (a disease from cows that produced
these sores). Jenner made these observations and decided to conduct an
experiment on his son. Jenner injected his son with the cowpox disease.
After his son recovered, Jenner injected him with smallpox. The boy
never contracted that disease, thus the first vaccination was created.
2. “Vacca” = cow in Latin, thus the name vaccination
3. Louis Pasteur – created rabies vaccination
3. How vaccines work:
a. a small amount of the dead virus is injected into you.
b. your body goes through the sequence of events
described previously
c. if at anytime after this you get infected with the virus,
your body already has memory cells made and it can
fight it off before symptoms appear.