MECHANISM OF PHAGOCYTOSIS

MECHANISM OF PHAGOCYTOSIS - Most microbes are killed by the...

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MECHANISM OF PHAGOCYTOSIS Lysosomal enzymes include lysozyme, which breaks down the peptidoglycan of the bacterial cell  wall. Other enzymes, including lipases, proteases, ribonuclease, and deoxyribonuclease break  down other bacterial components. These enzymes are designed to work best at a pH of about 4,  so the phagocytic cell pumps H+ ions into the phagolysosome.  Other enzymes that work against  the phagocytized bacteria include enzymes that produce superoxide radicals, hydrogen peroxide,  singlet oxygen, and hydroxyl radicals. These are produced in the phagolysosome and are  concentrated enough to kill even bacteria which produce protective enzymes.    The indigestible material that remains in the phagolysosome is called a residual body. It moves  toward the boundary of the cell and discharges its contents outside the cell. 
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Unformatted text preview: Most microbes are killed by the process of digestion. Unfortunately, some are able to survive. Some microbes produce toxins which kill the phagocyte. Others produce enzymes that destroy the membrane of the phagolysosome. These may even live and reproduce inside the phagocyte, where they are protected against antibiotics. Some microbes deliberately invade phagocytes to hide from the immune system of the host. They are able to prevent the lysosomes of the phagocytic cell from fusing with the phagocytic vesicle. They may immediately reproduce inside the phagocytic cell or remain dormant for months or years. Bacteria which are usually not killed include: I. Coxiella II. Actinobacillus III. Listeria IV. Shigella V. Staphylococcus VI. Mycobacterium...
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MECHANISM OF PHAGOCYTOSIS - Most microbes are killed by the...

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