19507643
Description
Flashcards by Genesis James, updated more than 1 year ago
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Created by Genesis James
about 5 years ago
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| Question | Answer |
| Microfold (M) cells | function in luminal antigen sampling by transporting luminal substances across epithelium to underlying APCs - utilized by salmonella and shigella as a route of invasion through mucosal barrier |
| Paneth cells | - defensin production (poke holes in pathogens to lyse them |
| Peyer's Patches |
enriched in lymphoid tissue:
- key sites for coordinating immune responses to pathogens
- promote tolerance to harmless microbes and food
- contain M cells
Image:
Peyers Patch (image/jpeg)
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| Neutralization of microbes in the lumen is done by... | ...secretory IgA and IgM in the lamina propria |
| Antibiotic peptides | kill pathogens or reduce their entry into epithelium |
| intraepithelial lymphocytes (IELs) | - innate lymphocytes and memory T cells - eliminate infected and damaged cells - help shape subsequent adaptive immune responses |
| lamina propria lymphocytes (LPLs) | - memory T cells : B cells = 4:1 - NK and plasma cells - IL-22 from Th17 cells helps maintain epithelial cell barrier - plasma cells secrete IgA |
| intestinal dendritic cells | - project dendrites between epithelial cells for antigen sampling - process and present antigens from microbes |
| serum IgA | circulates as a monomer in the serum (very little) |
| secretory IgA | - dimer with J chain found in fluids - secretory chain makes it more resistant to proteolytic cleavage by enzymes found in external body fluids - does not activate complement (IgG or pentameric IgM) - prevents binding of pathogens to host cells |
| Rotavirus symtpoms | - destruction of absorptive enterocytes by inducing apoptosis - virus-induced down-regulation of expression of absorptive enzymes |
| rotavirus immunity | IFN-g and IgA |
| attenuated vaccine (sabin vaccine against polio) | - virulent pathogen introduced into non-virulent host - pathogen learns how to survive in a non-human host, so it loses it virulence factors in humans - when introduced into human hosts, Abs are produced against pathogen without it causing harm - only one booster needed - humoral and cell-mediated immunity - HOWEVER, pathogen can revert back to virulent form |
| killed vaccine (silk vaccine against polio) | - virus is killed via chemicals or radiation with g-rays - multiple boosters needed due to inefficient mimicking of original virus OR different route of transmission - mainly humoral immunity - CANNOT revert back to virulent form |
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