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adaptive immunity
cmbm exam III
40
Chemistry
Graduate
01/10/2010

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Term
what are the primary lymphoid organs? what happens in it?
Definition
the thymus and bone marrow, where lymphocytes are actually generated. this is where selection processes take place, self-reactive lymphocytes should be eliminated and in the thymus, every cell is checked for compatibility with MHC. naive lymphocytes are found here, (have not seen antigen).
Term
what are secondary lymphoid organs? what happens here?
Definition
tonsils, adenoids, spleen, (blood filter), lymph nodes, (drain almost every area of the body), and mucosal surfaces, (GI, RT). this is where the work occurs, and where all lymphocytes are found
Term
what is a normal size for lymph nodes except in the inguinal area?
Definition
<.5 cm
Term
what do secondary lymphoid organs do in terms of antigen?
Definition
dendritic cells bring antigen to secondary lymph organs from common portals of entry, (RT, GI,skin), where it is concentrated, processed and presented to T lymphocytes
Term
what do naive lymphocytes do?
Definition
naive lymphocytes migrate through the peripheral organs and initiate responses upon antigen encounter
Term
what does the anatomy of secondary lymphoid organs promote? what do they generate?
Definition
cellular interactions required for the activation phase of adaptive immune response. secondary lymphoid organs generate memory and effector cell populations that migrate the periphery
Term
what does the anatomy of secondary lymphoid organs promote? what do they generate?
Definition
cellular interactions required for the activation phase of adaptive immune response. secondary lymphoid organs generate memory and effector cell populations that migrate the periphery
Term
what is the difference between humoral and cell mediated immune response?
Definition
humoral immune responses by definition include the production of antibody, (antibodies are dealt with by B lymphocytes, but T cells can help, leading to neutralization/opsonization). cell mediated immunity typically is induced by intracellular infection, (chlamydia or viruses), and requires T cells, (which require APCs like dendritic cells), that then produce cytokines, leading to proliferation of macrophages, cytotoxic T cells, etc, and enhance the cytotoxicity of these cells via INF-gamma
Term
do B cells require APCs?
Definition
no
Term
what are the three major subsets of B cells?
Definition
marginal zone B cells, follicular B cells, and B-1 B cells
Term
what are marginal zone B cells?
Definition
marginal zone B cells respond to blood borne polysaccharide antigens, (T cells are not involved here, b/c they only see protein)
Term
what are follicular B cells?
Definition
these make up the majority of B cells, make bulk of T dependent, class switched high affinity antibody responses to protein antigens. they also give rise to plasma cells.
Term
what are B-1 B cells?
Definition
these are important in making antibodies to non protein antigens at mucosal site and in the peritoneum. typically not found in lymph nodes.
Term
what are T-lymphocytes centrally important to? where are they derived from?
Definition
adaptive antigen-specific immune responses. they are derived from the Thymus gland.
Term
what are the 2 major types of T cells?
Definition
CD4+ and CD8+
Term
what do CD4+ T cells do?
Definition
most are helper/inducer, some are Tregs that make cytokines, some regulate afferent, (generation), and efferent, (effecting the response), arms of many types of response, via production of antibody, generation of cell mediated immune response. there are usally 2x more CD4+ than CD8+.
Term
what do CD8+ cytolytic T cells do?
Definition
these T cells are cytoxic or cytolytic for cells bearing the relevant antigen, and may also regulate the immune response
Term
what is the molecular basis for antigen specificity in B lymphocytes?
Definition
the receptor structures on lymphocytes.
Term
what gives T cell receptors/B cell surface immunoglobulins their overall structure and functionality?
Definition
the constant domains
Term
what is the difference between T-cell receptors and B cell surface immunoglobins?
Definition
T cell receptors are not 4 light+heavy peptide chains, they only have 2, (alpha+beta chains)
Term
are both T cell and B cell receptors members of the immunoglobin superfamily?
Definition
yes
Term
what is the structure of B lymphocyte surface immunoglobulins?
Definition
the B lymphocyte surface immunoglobulin has 2 variable region, (antigen-binding site), on its 2 light+heavy chain pairs allowing for a high degree of specificity
Term
what do most CD4+ and CD8+ T cells have?
Definition
an alpha/beta chain TCR, (T cell receptor)
Term
what 2 things does the antigen specific end of T cell receptors recognize?
Definition
the foreign protein as well as the polymorphic residue of the MHC. the foreign protein is actually anchored in a pocket of the MHC.
Term
how many T cells have gamma/delta T cell receptors? what role do they play?
Definition
only a minority of T cells have gamma/delta T cell receptors. they have a limited diversity in antigen specificity, however they recognize non-peptide antigens w/out processing and presentation via MHC. they may be an important first line of defense in the skin and gut.
Term
what are the three kinds of specific immunity?
Definition
active, passive, adoptive
Term
what are the two kinds of active, (self-made), specific immunity?
Definition
natural, via infection or artificial via vaccination
Term
what are the two kinds of passive, (aquired), specific immunity?
Definition
natural, via transplacental/colostral antibody transfer, or artificial, via administration of immune globulins
Term
what is adoptive specific immunity?
Definition
transfer of immune cells, doesn't really work in humans due to differences in immune systems
Term
what are the cardinal features of an adaptive immune response?
Definition
specificity, diversity, adaptibility, memory, clonal explansion, specialization, self-limitation, discrimination of self
Term
how does specificity play a role as a cardinal feature of the adaptive immune response? what is it a function of?
Definition
an adaptive immune response must be specific for distinct antigens, which is a function of distinct antigen receptors on the lymphocyte surface, (which should be present before exposure to antigen). specificity is the basis of clonal selection theory.
Term
how does diversity play a role as a cardinal feature of the adaptive immune response?
Definition
the total number of antigenic specificities of lymphocytes in an individual is large, (at least 1,000,000,000 different antigens), resulting in incredible antigen receptor variablility among lymphocytes.
Term
how does adaptibility play a role as a cardinal feature of the adaptive immune response?
Definition
the immune system needs to have the ability to respond to antigens not previously found in nature.
Term
how does memory play a role as a cardinal feature of the adaptive immune response?
Definition
the exposure of antigens to the immune system enhances its ability to respond again, and upon secondary infection, the response is faster, bigger, and qualitatively different
Term
how does clonal expansion play a role as a cardinal feature of the adaptive immune response?
Definition
clonal expansion increases the number of antigen-specific lymphocytes to keep pace with microbes during an infection, these clones are thus specific for the particular pathogen. this is why lymph nodes enlarge.
Term
how does self limitation play a role as a cardinal feature of the adaptive immune response?
Definition
the immune response should wane with time in proportion to antigen elimination. effector cells are thus short lived.
Term
does discrimination of self/non-self play a role as a cardinal feature of the adaptive immune response?
Definition
yes
Term
what is clonal selection theory? (4 main points -> will def be on test)
Definition
1) every individual contains numerous clonally derived lymphocytes
2)each lymphocyte has an antigen receptor specific for a single antigen, (all antigens on a lymphocyte are identical; one lymphocyte -> one specificity)
3)antigen receptors are present prior to antigen exposure
4)the antigen selects a pre-existing clone and activates it, (the receptor is there prior to contact)
Term
what are the major cells involved with innate immunity?
Definition
granulocytes, monocytes
Term
what are the major cells involved with aquired immunity?
Definition
B+T lymphocytes, (though dendritic cells, macrophages, and monocytes play a critical role in developing aquired immunity)
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