Term
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Definition
| Failure of immune system to react to self (what is present in the body all the time). An acquired skill that is learned (i.e. not encoded in our genes). Occurs through clonal abortion, clonal anergy and regulation by T cells. |
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Term
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Definition
| Small genetic variations between individuals within a species. About 0.1% difference in the DNA sequence exists between individuals in the human population. |
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Term
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Definition
+ Fab fragment: Highly variable area to which antigen binds.
+ Fc fragment: Constant area which mediates effector functions such as enhancing phagocytosis, interacting with complement and binds to cells. |
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Term
| Primary response to antigen |
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Definition
| 3 day delay before a peak in IgM is observed due to clonal expansion. Another peak of IgG is seen at 5 days. |
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Term
| Centra dogma of molecular biology |
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Definition
| Sequence information is one-way flow from DNA to RNA to protein. This is only broken in retroviruses which go RNA to DNA to RNA to protein. |
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Term
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Definition
| + By antigen: Exposure to antigen + T cell help |
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Term
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Definition
| The Fab of antibodies bind to antigen on pathogens. The Fc portion binds to receptors on phagocytic cells, increasing efficiency of phagocytosis. |
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Term
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Definition
| Small proteins secreted by CD4 T cells and act on many other cells inc. B cells, CD8 T cells and macrophages. They act locally and cause cellular activation and modulation of cellular activities. |
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Term
| Zinkernagal/ Doherty experiments |
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Definition
| Discovered graft rejection and destruction of virally infected cells were opposite sides of the same coin and that the real function of MHC is to present antigen to T cells. |
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Term
| Major histocompatibility complex |
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Definition
| Aka HLA in humans. It is a cluster of genes that encode for proteins on the surface of cells. MHC class I presents antigen synthesised within the cell denoting self to T cells. |
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Term
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Definition
| Helper T cells which activate B cells on activation by secreting cytokines which bind to receptors on B cells and direct cell to cell contact. |
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Term
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Definition
| Killer T cells. Upon activation killer T cells kill cells with non-self antigen on MHC class I molecules by punching holes in the cell membranes by release of perforins and release of proteases which initiate the apoptosis cascade. |
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Term
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Definition
| Memory cells are created after clonal expansion in a primary immune response. Thus next time one is exposed to the antigen, the body can respond faster, stronger, longer and with IgG. |
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