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20 Cards in this Set
- Front
- Back
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the acquired immune system has millions of lymphocyte ?, each recognizing a specific ?
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clones
antigen |
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chemical types of antigens
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usually proteins or polysaccharides; some lipids or bacterial DNA
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define an epitope
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segment of an antigen that a lymphocyte reacts with
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describe clonal selection theory
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each lymphocyte clone reacts to one antigen (epitope) only due to specific antigen receptor molecules in plasma membrane
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define an autoimmune disease & give examples.
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-immune system fails to make the distinction between friend & foe
-myasthenia gravis, Type I diabetes, lupus, psoriasis, Graves' disease, rheumatoid arthritis, multiple sclerosis |
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3 classes of lymphocytes
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T-cells (cell-mediated responses)
B-cells (secrete antibodies) NK cells |
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describe development of B-cells & name proteins on its surface
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develop from lymphoid stem cells in bone marrow; become "immunologically competent" & express B-cell receptor proteins (BCR) on the surface to enable them to recognize antigens
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describe development of T-cells & name proteins on its surface
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lymphoid stem cells in bone marrow migrate to thymus where they mature; apoptosis occurs in T-cells that recognize self-antigens
CD4, CD8, TCR |
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describe the circulation of lymphocytes around the body
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continuously circulate between lymphoid tissue, lymph, and bloodstream
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describe the 3 ways clones of lymphocytes react on exposure to an antigen
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-lymphocytes divide
-lymphocytes are activated -some lymphocytes "remember" the antigen |
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define self-tolerance & how it is achieved.
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immune system learns not to respond to its own antigens
clonal deletion & clonal conversion |
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define an antibody
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glycoproteins that bind to foreign antigen; produced only by B-lymphocytes
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2 ways antibodies act
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-inactivate foreign organisms & toxins by masking active sites in antigen molecule
-tag organisms & cells for destruction by complement or WBCs |
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shape of antibody? function of various parts?
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Y shape
-each arm binds an antigen -tail determines what happens once antigen has been bound |
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5 classes of Ig
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IgM: first responder, pentamer, powerful activator of complement
IgG: secondary antibody response, crosses placenta, activates complement (less than IgM), opsonizes cells IgA: in mucus, tears, milk, exists as a dimer IgD: on B-cells & in plasma, immunoregulatory function IgE: on mast cells & basophils (release histamine when IgE is bound by antigen), allergic response |
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function of antigens and IgE in allergic reactions
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antigens that bind to IgE trigger the inflamm. response, attracts eosinophils to attack parasites
allergies are caused by overproduction of IgE to pollen, foods, etc. |
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2 treatments for allergies
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-antihistamines
-antibodies against IgE |
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define complement & explain why it is important
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30 proteins in blood
important because w/o it people are susceptible to bacterial infections, antigen-antibody complexes precipitate in small blood vessels leading to acute inflamm. & tissue destruction |
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2 ways complement is activated
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-classical: activated by IgM or IgG complexes
-alternative: activated by foreign carbohydrates in the envelope of bacteria & viruses (immediate response) |
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5 consequences of complement activation
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-MACs form, putting holes in pathogens' membranes
-inflamm. - blood vessels dilated -inflammation - phagocytes attracted, mast cells stimulated -opsonization by complement -antibody-antigen complexes are made soluble, making them harmless (can't clog blood vessels) |
