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17 Cards in this Set
- Front
- Back
In what ways are pathogens able to avoid being destroyed by a host |
- hiding within a host cell - avoiding through complement system proteins - avoiding destruction from phagocytosis - avoiding antibodies - damaging the host |
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How can a pathogen avoid being englufed by phagocytes |
- prevent encounters with phagocytes - c5a peptidase - degrades c5a - membrane damaging toxin - kill phagocyte - avoid recognition and attachment - capsules - interfere with opsonzation - M protein - inactivates c3b - fc receptors - bind to Fc region of antibodies - surviving inside phagocyte - escape phagosome - prevent phagosome lysosome fusion - survive within phagolysosome |
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How can a pathogen avoid antibodies |
- IgA protease - cleaves IgA molecules - Antigenic variation - changing structure of surface antigens - mimicking host molecules - pretending to be host cell |
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Differentiate between endotoxin and exotoxin |
- exotoxins - gram positive or negative, protein, potent, heat inactivated - endotoxins - gram negative only, Lipid A, localized amounts yield mild response, systemic can be deadly, heat stable |
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what are some damaging effects of immune response |
- inflamation - phagocytes can release toxic products - adaptive immunity - immune (antigen-antibody) complexes can form and settle into body activating complement system - cross reactive antibodies - bind to host tissue, autoimmune response |
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How are viruses able to avoid immune response |
- avoiding effects of interferons - block expression of host genes or activation of enzymes - avoiding antibodies - move cell to cell or cause cell fusion - motify surface antigen - use antibodies to facilitate macrophage uptake - regulating host cells death - block or present conterfit MHC class I molecule |
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Differentiate between artificial and natural active and passive immunity |
- natural active - infection by bacteria - artificial active - immune response after vaccination - natural passive - antibodies from mother - artificial passive - antibodies from other people or animals in vaccination |
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Types of inactivated vaccines |
- inactivated whole agent vaccines - toxoid - subunit - consist of key protein or antigen - recombinant - subunit made from genetically engineered microorganism - VLP (virus-like particle) - empty capsid made from genetically engineer microorganism - conjugate - polysaccharides + proteins |
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Seronegative, Seropositive, Seroconversion |
- Seronegative - individual not yet exposed to antigen - Seropositive - individual exposed to antigen - seroconversion - process of producing antibodies, takes 7 - 10 days |
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Bacteriostatic vs bactericidal |
- -static - inhibits bacterial growth, hosts defenses still need to kill bacteria - -cidal - kill bacteria |
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What causes some antimicrobials to differ in the body |
- only some can cross blood stream into CSF - some affected by low pH, must be injected - length of half life dictates frequency - kidney or liver disfunction can differ |
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What causes resistance to antimicrobial drugs |
- innate resistance - lacking cell wall, thick outer membrane of gram-negative bacteria - aquired resistance - spontaneous mutation (combination therapy prevents), horizontal gene transfer (through R plasmids |
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Antibacterial drugs that inhibit cell wall synthesis |
- penicillins, vancomicin - B-lactam ring competetively inhibits enzymes that form peptide bridges between glycan chains - side chains modified to create derivatives - natural, penicillinase- resistant, broad spectrum, extended spectrum, + B-lactamase inhibitor |
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bacterial drugs that inhibit protein synthesis |
- exploit difference in prokaryote ribosomes (70s 50s+30s) - tetracyclines - block tRNA - Macrolides - prevent continuation of protein synthesis |
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antibacterial drugs that inhibit nucleic acid synthesis |
- fluoroquinolones cause strands to unwind - rifamycins block rna polymerase |
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antibacterial drugs that interfere with metabolic pathways |
- folate inhibitors - inhibit synthesis of folic acid - sulfonamides, trimethoprin |
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MIC determination |
- MIC (minimum inhibitory concentration) is lowest concentration that prevents growth - Kirby- Bauer disc diffusion test - MBC lowest concentration that kills 99.9% of bacteria in vitro |