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36 Cards in this Set
- Front
- Back
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physical/chemical barriers |
part of innate (nonspecific) immune system include tears (contain lysozymes that digest bacterial cell walls) include mucus secretions and cilia in lungs (that trap and expel particles) include low pH in stomach which kills bacteria and includes defensins on skin, which are antibacterial enzymes |
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complement protein pathways |
part of innate immune systems punch holes in bacterial cell walls in the bloodstream can be activated by alternative pathway (does not require antibodies) or classical pathway (uses antibodies bound to pathogens- all pathogens (indiscriminate)) |
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interferons |
part of innate immune system prevent viral replication and dispersion by
-limiting permeability of cells to viruses, slowing protein production of nearby cells, upregulating MHC1 and MHC2 so there is more antigen presentation responsible for flu-like symptoms of viral infections |
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Inflammation |
cell-mediated defense increases heat and blood flow so less hospitable to pathogens induced by chemical signals released from damaged tissue cells and immune cells already present in tissues including mast cells, macrophages and dendritic cells alerts immune system that something is wrong |
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phagocytosis |
done by macrophages, white blood cells that eat bacterium (located by pathogenic peptides) |
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antigen presentation |
after broken down in macrophage to smaller polypeptides - MHC binds antigens and carries to cell surface displayed antigens recognized in lymph or blood by adaptive immune system cells |
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macrophages |
agranulocytes that engulf pathogens arise from monocytes which are triggered to become macrophages by bacterial invaders in tissues release cytokines which stimulate inflammation and recruit additional immune cells |
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Major Histocompatibility Complex Class I |
Class I displayed by all nucleated cells also break down and display normal proteins, so presentation of non-self molecules indicates infection and triggers response endogenous pathway, binds antigens that originated inside cell |
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Major Histocompatibility Complex Class II |
Class II molecules are mainly displayed by immune cells exogenous pathway, bc binds antigens that originated outside cell |
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Natural Killer Cells |
not first resort called in once virus invades cells and manages to downregulate MHC molecules, making it harder for T-cells to recognize infection bc no peptides on cell surface NK cells detect downregulation and induce apoptosis of infected cells |
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granulocytes |
include neutrophils, eosinophils, basophils participate in inflammatory response |
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neutrophils |
white blood cells are short lived phagocytic leukocytes that eat bacteria follow bacteria via chemotaxis can detect bacteria that have been opsonized (marked w/ antibody by B-cell) |
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eosinophils |
release histamine (inflammatory mediator) after activation by allergic reactions or invasive parasitic infections allow immune cells to move out of bloodstream and into interstitial space around injured tissue |
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basophils and mast cells |
release large amounts of histamine in response to allergens basophils have large purple granules mast cells exist in mucosa, epithelium (exposed to outside world) |
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B-cells |
govern humoral adaptive immune response in charge of antibodies mature in bone marrow, activated in spleen and lymph nodes |
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antibodies |
aka immunoglobulins specific to microbe's antigens can be on cell surface or secreted by lymphocytes into body fluids |
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opsonization |
when antibody in body fluid binds to antigen, can attract other leukocytes to phagocytize the pathogen |
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agglutinization |
antibodies can cause pathogens to to clump together to form large insoluble complexes that can be phagocytized |
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neutralization |
antibodies can block a pathogen from invading tissues, essentially neutralizing them, since they can't infect new cells |
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plasma and memory cells |
triggered by B-cells, which are activated when antigen binds to an antibody on surface of healthy host cell from previous infection |
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mast cells |
when antigens bind to antibodies on mast cells, degranulation occurs, release of histamine, inflammatory response |
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antibody structure |
heavy and light chains joined by disulfide linkages and noncovalent interactions variable region binds only one specific antigen sequence |
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hypermutation |
leads to clonal selection. variable region mutated to find best match for antigen- only B/T cells specific to pathogen are activated |
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constant region of antibody |
allows for initiation of complement cascade- binds natural killer cells, macrophages, monocytes, eosinophils |
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isotype switching |
B-cell changes constant region to bind different effector molecules stimulated by specific cytokines |
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naive b-cells |
before exposure |
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plasma cells |
B-cells produce after exposure to matching antigen produce large amounts of one antibody |
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memory B-cells |
B-cells produce after exposure to matching antigen involved in secondary response, stay in lymph nodes if microbe seen already reenters, produce antibodies specific to that pathogen |
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T-cells |
mature in thymus by positive selection (cells that can respond to presentation MHC antigen) or negative selection (causing apoptosis in cells that are self-reactive) |
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thymosin |
regulates maturation of T-cells |
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Helper T-cells |
(CD4+) secrete lymphokines to coordinate immune response respond to MHC2 loss of these causes HIV 2 types: Th1 release interferon gamma, which activates macrophages) Th2 help activate B-cells |
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lymphokines |
secreted by helper t-cells, increase activity of other immune cells |
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cytotoxic T-cells |
CD8+ induce apoptosis of infected cells respond to antigens on MHC1 cells (which are not immune specific) inject toxic chemicals into virally infected cells |
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suppressor/regulatory T-cells |
help moderate immune response turn off self-reactive lymphocytes, either by targeting them for destruction or turning into suppressor T-cells similar to helper T-cells but have Foxp3 gene |
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Memory T-cells |
similar to memory b-cells more rapid, robust response |
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allergen path |
1st time, B-cells recognize allergen protein, and plasma cells release antibodies Antibodies activate mast cells NExt time, mast cells release histamine and cytokines |
