First Aid Immunology Flashcards
IgG
main antibody in secondary (delayed) response to antigen. Most abundant isotype in the serum. Fixes complement Crosses the placenta (passive immunity) Opsonizes bacteria Neutralizes bacterial toxins and viruses
IgA
Prevents attachment of bacteria and viruses to mucous membranes. DOES NOT fix complement. Monomer in circulation, but dimer with J chain when secreted. Crosses epithelial cells by transcytosis. Produced in GI tract Peyers patches and protects against gut infections like giardia.
It is the most produced antibody overall, but low serum levels.
IgM
Produced in the primary (immediate) response to an antigen. Fixes complement, does not cross the placenta. It is the antigen receptor on the surface of Bcells. Monomer on the B-cell, but a pentamer with J chain when secreted.
IgD
unclear function
IgE
Binds mast cells and basophils. CROSS LINKS when exposed to antigen. Mediates type hypersensitivity through the release of inflammatory mediators such as histamine.
Acute Phase Reactants
factors whose serum concentrations change in response to inflammation. Produced by the liver in both acute and chronic inflammatory states. Notably: induced by IL-6.
Important cytokines secreted by MACROPHAGES
IL-1 - causes fever, acute inflammation, activates endothelium to express adhesion molecules.
IL-6 - Causes fever and stimulates production of acute phase proteins.
IL-8 major chemotactic factor for neutrophils “clean up on aisle 8”
IL-12 - induces differentiation of T-cells to Th1.
TNF- alpha - mediates septic shock. activates endothelium. Causes WBC cell recruitment. Vascular leak.
Important cytokines from Th1 cells
Interferon-y - stimulates macrophages to to kill phagocytosed pathogens. Inhibits differentiation of Th2. Increases MHC expression and antigen presenting cells.
Important cytokines from Th2 cells
IL-4 - induces differentiation of T cells into Th2. Promotes B-cell growth. Enhances class switching IgE to IgG.
IL- 5 - promotes growth and differentiation of B-cells. Enhances class switching to IgA. Stimulates growth and differentiation of eosinophils.
IL-10 - ATTENUATES inflammatory response. Decreases expression of MHC class 2 and Th1 cytokines. Inhibits --> NOTE both TGf-beta and IL-10 attenuate the immune response.
Superantigens
(i.e. strep pyogenes, s aureus) cross link the B-region of the tcell receptor to the MHC complex on APCs. this can activate CD4 tcell leading to a massive release of cytokines.
endotoxins
i.e. lipopolysaccharide gram negative bacteria. DIRECTLY stimulate macrophages by binding to endotoxin receptor TLR4/CD14, Th cells are not involved.
Classic examples of antigenic variation
Salmonella - 2 flagellar variants N gonorrhea pilus protein Viruses: HIV Flu
Live attenuated vaccine
microorganism with retained pathogenicity, but capacity for transient growth in innoculated individual. CELLULAR and HUMORAL response.
Inactivated or killed vaccine
pathogen inactivated by heat or chemicals. maintaining surface epitope. mainly induces humoral response.
Important live attenuated vaccines
intranasal flu
mmr
varicella
yellow fever
important killed vaccines
flu IM
rabies
polio
hep A
anti ACh receptor
myasthenia gravis