Gonococcal interactions with polymorphonuclear neutrophils: importance of the phagosome for bactericidal activity.
AUTOR(ES)
Densen, P
RESUMO
Gonococci are capable of attaching to the surface of polymorphonuclear leukocytes (PMN). In this location they resist phagocytosis and are not killed by PMN. To delineate the factors involved in the survival of these gonococci, we investigated the interaction of virulent gonococci, which adhere to cells and resist phagocytosis, and avirulent gonococci, which are phagocytized and killed by PMN. In the presence of serum, both virulent and avirulent gonococci associate equally well with PMN and stimulate increases in oxidative metabolism. In the absence of serum virulent gonococci attached to PMN and stimulated PMN oxidative metabolism to a greater extent than avirulent gonococci which did not attach to PMN (P = 0.0009). Therefore, the survival of virulent gonococci attached to the PMN surface is not a result of failure to activate oxidative and bactericidal mechanisms. Both virulent and avirulent gonococci stimulated equivalent PMN specific granule release as measured by the appearance of lactoferrin in the media. Phagocytosis of avirulent gonococci stimulated significantly greater beta-glucuronidase release (P = 0.01) and myeloperoxidase-mediated iodination of protein (P = 0.001) by PMN than attachment of virulent gonococci. In the absence of serum neither type of gonococci stimulated beta-glocuronidase release or protein iodination by PMN. Thus, virulent gonococci fail to stimulate primary granule release by PMN. To further assess the role of attachment versus ingestion on the survival of gonococci, PMN were treated with cytochalasin B to block ingestion. Cytochalasin B-treated PMN were unable to kill either virulent or avirulent gonococci despite normal degranulation stimulated by the latter. The failure of PMN to kill surface-attached gonococci appears to be a consequence of the failure of PMN to enclose the virulent gonococci within a phagosome. The phagocytic vacuole thus plays a critical role in normal PMN bactericidal activity by providing a closed space in which the proper concentration of substances may be achieved to generate microbicidal activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=371880Documentos Relacionados
- Bactericidal Activity of Aerobic and Anaerobic Polymorphonuclear Neutrophils
- Interactions of Neisseria gonorrhoeae with Human Neutrophils: Effects of Serum and Gonococcal Opacity on Phagocyte Killing and Chemiluminescence
- Inhibition of neutrophil lysosome-phagosome fusion associated with influenza virus infection in vitro. Role in depressed bactericidal activity.
- Bactericidal Activity of Specific and Azurophil Granules from Human Neutrophils: Studies with Outer-Membrane Mutants of Salmonella typhimurium LT-2
- Degradation of gonococcal peptidoglycan by granule extract from human neutrophils: demonstration of N-acetylglucosaminidase activity that utilizes peptidoglycan substrates.