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Erstellt von Sophie Byrne
vor fast 6 Jahre
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Frage | Antworten |
Why do pathogens invade host cells? | Intracellular = privileged envt - Immune sys protection - No Abs or complement - Nutrient and tissue access |
4 examples of invasive pathogens | Salmonella enterica Mycobacterium tuberculosis Candida albicans Shigella spp |
How does Mtb invade host cells? | Phagocytosed by resident alveolar macrophages Mtb arrests vacuole - phagosome can't fuse w/ lysosome --> no acidification --> Mtb not killed Nutrients delivered to arr vac by Golgi Waste removed |
How does Salmonella enterica invade cells? | Pathogen-dependent phagocytosis: T3SS inserted into epithelial cell (M cell or enterocyte in gut) Releases effectors into host cell Effectors cause rearracgeent of actin cytoskeleton --> cup-like structure Bacterium taken up by host cell Enclosed in vacuole - shrinks and solidifies SP12 T3SS activated - secretes effectors - controls nutrient delivery by Golgi to cell May exit cell via basal membrane - other body tissues |
How does Shigella invade host cells? | Similar to Salmonella mechanism M cell actin cytoskeleton remodelling using T3SS effectors Taken up by PDP Lyses vacuole once in host cell No flagellum - uses host actin to propel self - uses lots of host cell ATP May travel through double memb b/w cells May exit via basal memb Phagocytosis - may exit macrophage by inducing apoptosis Access to other host tissues |
How does Candida albicans become invasive? | Change in pH, [CO2], temp Morpho change to hyphal form Hyphae dig into tissues (facilitated by phospholipases secreted at tip e.g. caPLB1) Reach blood vessel and break off/yeast budding off tip Spreads round body to other tissues and organs e.g. kidneys |
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