Nonspecific Host Defenses

Nonspecific Host Defenses - Nonspecific Host Defenses -...

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Nonspecific Host Defenses - Barriers, formed blood elements, inflammation, complement = Initiation of phagocytosis requires adherence of the phagocyte to the microorganism · Adherence may be impaired by virulence factors such as capsules and cell wall proteins · Adherence may be enhanced by opsonization, coating of the microorganism with molecules produced by host cells = Ingestion of the microorganism involves extension of pseudopods and eventual envelopment of the microorganism in a membrane-bound phagosome. = Digestion of the phagocytosed microorganism is accomplished by fusion of the phagosome with lysosomes containing enzymes and toxic compounds · Lysosomal enzymes include enzymes catalyzing hydrolysis of the pathogen's macromolecules and oxidative damage · Some specialized pathogens are resistant to digestion and may actually kill the phagocyte - In addition to killing invading microbes, phagocytes also interact with other cells involved in host defense Tissue damage from infection leads to an
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