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Ag-
molecular structures that the immune sys can recognize and respond to
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Ag is a substance capable of....
- Inducing a SPECIFIC immune response
- Interacting with the products of that response
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Antigens the induce a response are recognized by (2):
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Antigens can interact with (4):
- Antibody
- TCR (T-Cell Receptor on T-Lymphs)
- BCR
- MHC
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Antigenicity-
The ability of an antigen to bind with immune components
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Immunogenicity-
The ability of an antigen to induce an immune response
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Properties of good immunogens (4):
- Small (<1kDa)
- Complex
- Moderate Stability
- Foreign
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Ex. of poor immunogens, based on complexity (
- Lipids
- Nucleic Acids
- Polymers (plastics, Bacillus anthracis, carbs)
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Epitope-
Part of the antigen that is recognized by the antibody, TCR or BCR
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Types of epitopes (2):
- Conformational (recognition based on folding)
- Linear (Recognized based on AA sequence)
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Cross Reactions-
An acquired immune response to the epitope of a similar bacteria or virus
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Two bacteria that can give false pos. due to cross reactivity?
- Brucella abortus (bad)
- Yersinia enterocolitica (insignificant)
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Haptens-
Small, antigenic molcules that can only induce an immune response if they are bound to a carrier protein
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Most microbial immunogenic molecules are...
- Proteins
- (some carbs and lipids)
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Extra/Intracellular pathogens-
Where a microbes replicates, outside/inside of the cell
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Intracellular pathogens include...
- most viruses and some bacteria
- (Can still survive outside of cell)
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Extracellular pathogens include...
Most bacteria and parasites
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Intracellular Bacteria (4):
- Mycobacterium
- Rhodococcus equi
- Listeria Monocytogenes
- Brucella abortus
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Ex/Endogenous Antigens-
- Where the antigen is made
- (vs extra/intracellular pathogens)
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Ex. of an endogenous antigen:
Mycobacterium bovis
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Ex. of a bacteria which has a capsule that protects it from immune response
Bacillus anthracis
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Two defining features of Mycobacterium, Rhodococcus equi, Listeria Monocytogenes and Brucella abortus
- Intracellular Pathogens
- Endogenous Antigens
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Viruses use the host's ___ to make ___
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It's difficult to create an HIV Vx b/c...
the envelope can vary it's antigenicty
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