PMI 126 - Lecture 6

PMI 126 - Lecture 6 - PMI 126 Lecture 5 (end of midterm I)...

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PMI 126 – Lecture 5 (end of midterm I) the building block for specificity of T and B cell are in the germ-line tremendous processes occur at DNA level to creates various receptors that are specific for certain antigen. The genes that are actually exist in T and B cells are not in the germ-line. o They are brought together randomly. o Those genes are not found in one pieces, unlike the gene encoding the pattern-recognition receptors. Antigen vs. Immunogen Antigen : ( refers to anything that T cell receptor or B cell receptor can bind ) - all antigens are not immunogens - receptors (antibodies and T cell receptors (TCR) of the adaptive immune response can specifically bind antigen - Antigenic determinant (epitope): the part of the antigen to which antibody/TCR actually binds o There are lots of epitope on the “single” foreign protein o Only antibody that binds to certain epitope will be neutralizing the ability of the virus get into the cell Immunogen: - all immunogens are antigens - it’s an antigen that can actually induce an adaptive immune response - what make a good immunogen? 1. foreignness (more foreign, the better immunogen) 2. Molecular size (> 100000 Kd ) 3. Chemical composition and complexity (more complex in structure/amino acid stand point, the better immunogen) (proteins probably the best immunogen around) 4. Susceptible to antigen processing and presentation (T cells only recognize “ processed ” antigen with MHC protein) Example: TB skin test - being infected/vaccinated = mount the immune response and generate the memory - when we take PPD (purified protein derivates) = piece of cell wall of the bacteria put on the skin o if you have been infected/vaccinated, you have memory cells specific for that proteins o memory cells migrate to the area where the piece of bacteria located. Memory cells can recognize it and bind to it. But it DOES NOT induce an immune response. PPD is NOT an immunogen. As a part of the bacteria, it can mount the immune response. However, it does NOT induce immune response (not immunogenic) when it’s by itself. Thus, PPD is the antigen that component of the immune system can recognize it without inducing the immune response. Improving Immunogenicity – Adjuvants
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This note was uploaded on 05/09/2010 for the course PMI PMI 126 taught by Professor J.l.stott during the Winter '10 term at UC Davis.

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PMI 126 - Lecture 6 - PMI 126 Lecture 5 (end of midterm I)...

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