Release of superoxide anion from resident and activated mouse peritoneal macrophages infected with Mycobacterium intracellulare.

Phagocytosis of Mycobacterium intracellulare triggered the release of superoxide anion (O-2) from mouse peritoneal macrophages; the amount release from BCG-activated cells was significantly greater than that from resident cells. Superoxide anion release was proportional to the number of phagocytes ingesting bacilli. An optimal phagocytic time course of 4 h was observed when estimating O-2 release consequent to bacterial challenge. Also, an inverse relationship between the amount of O-2 released and the virulence of M. intracellulare in mice was shown. Transparent and rough colony variants triggered the release of significantly lower amounts of O-2 as compared with the opaque and smooth colony variants. Serovars 4 and 8, which cause a disease with a poor prognosis in humans, triggered significantly less O-2 than did serovars 9, 12, 13, 14, 16, 18, and 19, which respond more favorably to chemotherapeutic regimens.