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chap 16 adaptive immune response
why is adaptive immune response important?
protects us from many infections
has memory so we are not infected by the same pathogen a 2nd time (this is why vaccinations work)
Adaptive immune response is the 2nd level of immunity. what does it involve?
it involves lympcytes
it is a response to specific antigens
it is exraordinarily specific
it can adapt to any infection
it has memory (life long immunity)
what are the 2 types of respnses
innate- prerequistie for adaptive immune response
adaptive immune response (2 types)
-humoral- production of antibodies
-cellular- killing and regulation og infected cells
define humoral and cellular responses.
carried out by B lymphocytes
Responsible for production of antibodies
activation of B cells usually requires help from T cells
some B cells proliferate and differentiate into plasama cells (produce massive amounts antibody)
Some B cells become memory cells
carried out by T lymphocytes (cytotoxic T and helper T cells)
responsible for killing and regulation of infected cells
T cells that have not seen antigen are considered naive, but after encountering antigen, both T cell types become armed effector T cells
where is the lymphatic system?
cover the entire body
lymphocytes and lymphoid structures
adaptive immune response is associated w/ it
what is the function of dendritic cells?
most important cells in the adaptive immune response
-have enormous surface areas- grabs antigen
-take up and process antigens
-present antigens to T cells
what is a clonal selection? fig 16.7
which some lymphocytes are destroyed and others are allowed to mature. this selection process takes place in the bone marrow for B cells and in thymus for T cells
how the immune system responds to infection
takes place in the bone marrow for B cells and in the thymus for T cells
lymphocytes that remain after clnal deletion maure
each is specific for nonself antigen
if an antigen is encountered, the lymphocye is activate (begins to divide and proliferate. It forms a clone of cells specific for one antigen)
lymphocytes that never encouter antigen eventually die
what are the 3 important points about clonal selection?
it generates a vast # of different antigen receptors
each receptor is specific for a different antigen
all progeny of that lymphocyte will have the exact same receptor
what do lymphid precursos T and B cells give rise to?
T cells- Cytotoxic (Tc) and Helper T cells
B cells- differentiate into plasma cells
what are the 2 types of helper T cells? what do they activate?
2 types of helper T cells-
Activate the B cells and macrophages
T cells are naive until they encouter antigens (co-stimulatory signals must be present)
when B cells and T cells mature, they acuire specific antigen receptors...
B cell receptor is an immunoglobulin molecule (2 antigen binding sites)
T cell receptor is similar to Ig (only 1 antigen binding site)
where do B and T cells originate form? where do T cells mature? Where do B cells mature? then what do they do?
B and T cells originate in bone marrow
T cells mature in the thymus gland (thymus atrophies at puberty, T cells are long lived, maturation requires specific signals)
B cells mature int he bone marrow
when mature, both circulate through the blood and tissues looking for antigens
maturation requires specific signals
lymphoid tissues, B cells. Tell me when B cells die?
most of them die when they reach the peripheral tissue
they are constanty replaced and therefore the # remains constant
what are the 3 functions of antibodies?
: antibodies neutralize toxins and virsuses and also prevent bacterial attachment ("staying in" requirment for infection)
: antibodies facilitate the uptake of pathogens by phagocytic cells
complement activation system
: antibodies activate the classical pathway of the complement system
name the 5 antibody isotypes?
IgM, IgG, IgA, IgE, IgD
first antibody to be produced in a humoral response
usually found in blood
excellent activator of the complement system
primary response to bloodborne pahtogens
found in pleural spaces (protects enviro pathogens)
what is IgA?
principle antivody in secretions
found in respiratory and digestive tract
it is not very effective in activating the complement system
found in colostrum (transfered from mom to child. protects against newly encountered bacteria)
what is IgG?
principal isotope in the blood and exracllular fluid
very effective for opsionization and activation of complement
newborns recieve (can cross the placenta)
what is IgE?
found in low levles in the blood and extracellular fluids
binds tightly to mast cells just below the skin and mucosa
it is also found along the blood vessels in connective tissue
after antigen binding, powerful chemical mediators are released (causing coughing, sneezing, vomitting)
what is IgD?
found in very small amounts in the blood
it is found on the surface of B cells
has no known function in serum
it is involved as an early antigen receptor
Tell me about T cell response
cellular immune cell response is generated by T cells (cytotoxic and helper T cells)
T cells that have not seen antigen are considered to be naive
after encountering antigen, both types become armed effector T cells
what are the 3 classes of armed effector T cells
Th1 helper- provide activation signals for macrophage
most of these move into the blood when they are activated
cytotoxins are released by cytotoxic T cells
cytokines are released by helper T cells
what is one of the most improtant properties of adaptive immune response? what form can it be seen in? what is the memory due to? what due interlukins help do?
immunological memory is most important
seen in both T and B cells and is produced after infection or vacination
memory is due to persistent population
Interleukins help maintain the memory T cell pop
when does innate and adaptive response take place?
innate= early stages of infection
adaptive= few days after 1st exposure to antigen
once the pathogen is estab. only adaptive can rid of it
explain the immunity to infection
explain adaptive response