Exam 4 Review - Summary Microbiology PDF

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Exam 4 review guide...

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cells of the immune system: - cytokines/ chemokines= proteins that influence many aspects of immune cell differentiation - APC’s • macrophages - first defense cells that interact with a pathogen - abundant in many tissues • Dendritic cells - phagocytes that specialize in presenting antigen to lymphocytes - neutrophil • contains toxins or enzymes that are released to kill target cells - Lymphocytes • B Cells - originate in bone marrow - specialized APC’s and precursors of antibody producing Plasma cells - produce antibodies/ immunoglobulins (Igs) - B cell receptors (BCRs)= cell-surface antibodies on a B cell

- activated by Th2, B cells can differentiate into plasma cells which produce antibodies

- They can also differentiate into memory B cells which store the antigen for a secondary response where they differentiate into plasma cells

• T Cells - develop in bone marrow but mature in thymus - interact with particular antigens - T cell receptors (TCRs) = antigen-binding proteins of T cells

- Th1 cells recognize MHCII and stimulate cytokines which signal phagocytosis -

and more APCs Th2 cells attract B cells ThC cells recognize MCHI and stimulate cytokines and destroy the cell

bacterial pathogens - N. gonorrhoeae • binds to mucosal epithelial cells in the genitourinary tract, eye, rectum, and throat • cell surface protein Opa that binds specifically to host protein CD66 - Botulinum • uses AB toxin to block the presynaptic membranes of the stimulatory motor neurons blocking the release of acetylcholine • prevents muscle contraction - Cholera • B subunit targets the toxin specifically to the intestinal epithelium but has no toxicity itself • A subunit causes toxicity when it crosses the cytoplasmic membrane and activates the enzyme to convert ATP to cAMP which induces secretion of chloride and bicarbonate from small intestine epithelial cells into intestine lumen • secretion of large amounts of water - Diphtheria - TSS - S. Aureus

viral pathogens - influenza • targets lung mucosal cells and attaches specifically to lung epithelial cels by way of protein hemagglutinin (HA) present on the virus surface • caused by RNA virus • singles stranded RNA genome surrounded by an envelope- uses reverse transcriptase or RMA replicase • zoonotic - HIV...