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BIOL 2900
Malini Persaud

Specific or Adaptive immunity  A response to a specific molecule (antigen)  The immune system can “remember” invaders and react more promptly to second exposures to infection o Only an exposure to the same antigen will activate this memory response  The specific immune system distinguishes between self and non-self and only reacts against non-self.  Specific response: can only recognize one specific antiegn  Immunological memory o Cellular (T cells) o Humoral (B cells)  Antibodies Humoral Adaptive Immunity  Antigens (ag) are substances that induce a specific immune response and subsequently react with the products of a specific immune response  Antibodies (Ab, immunoglobins, Ig) are protein molecules that are produced by plasma cells in reponse to an antigen and can bind specifically to that antigen o Antibodies are same on structures and have different regions on the antibodies. o Neutralization: antibodies are bound to virus or antigens, they can’t bind to cells. This attracts macrophages and phagocytosis happens o Agglutination: a group of antibodies go and attach itself to a bunch of antigens and this makes it easier for macrophages to engulf them. o Precipitation: has premolecules or proteins that circulates in the blood Function of Antibodies  An antibody molecule has two related functions in humoral immunity o Recognize and bind to a certain antigen o By binding to it, help to counter its effect:  Neturalization: Ab “neutralized” toxins, binds to attachment molecules  Aggutination: create complexes of cells  Precipitation: create complexes of molecules  Know the difference between them  Complement activation: occurs on antibody bound to pathogens (holes on cell membrane and cell lysis  Opsonization: Ab binds to pathogens surface molecules and link them to phagocyte cell (when Fc thas part of Ab bind to bacteria, Fc is stuck out. Opsonization to put salt on the meat to make it taste better. This can make the engulfment easier) How does the body develop antibodies BCR (B cell receptor) We have a problem: we need  To recognize a trillion of possible antigens, individually and specifically  Each lymph has a specific antibody that is expresses for its lifetime  In order to mount an effective response we need to have sufficient cell specific for the antigen in question (at least million cells)  It is not possible having 1 million x 1 trillion (10 ) cells in the body just for specific immunological response o Our body consists of 10 cells  clonal selection of lymphocytes Solution: Clonal Selection  the immune system has an extremely low frequency of cell specific for each of trillion of specificities (5-10/cell)  when a cell encouters its specific Ag, it replicates extensively, turning 5-10 cells into millions of progeny  Rare antigen-specific cells can increase in number so that they can get the ability to effectively fight the pathogen that elicited the response  Bcell is unique and only recognize one type of Ag. Mcells of abcteria is recognized by Mcells of humans which is drained into the lymph cyte. ASK KAITLIN TO EXPLAIN THIS CONCEPT~ CLONAL SELECTION ASK KAITLIN TO EXPLAIN WHY BACTERIOSTATIC IS PREFFER (ITS DUE ITS HAS BETTER THERAPEUTIC INDEX) Clonal selection and immunity  It’s the ability to make antibodies  Primary response is clonal selection. It is responsible for making antibodies for the first time your body is contacted with an Ag  Secondary response: when your body is used to the Ag. This is quicker than primary response. Development of immunologival memo.After exposure to Ag, memeoy cells will be activates to make Ab to fight the Ag. Immunological Memory  Immunological memory is the ability of the immune system to respond more quickly and effectively to pathogens that have been encountered previously  The primary immune response takes several days to produce effector cells via clonal selection  Clonal selection produces a
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