Listeria monocytogenes infection in mice treated with pentoxifylline

The production of nitric oxide and tumor necrosis factor by murine macrophages infected with mycobacterial strains differing by hemolytic activity

In this study, we compared the secretion of nitric oxide (NO) and tumor necrosis factor (TNF-alpha) by murine macrophages infected in vitro with hemolytic or unhemolytic mycobacteria isolates. We observed that unhemolytic mycobacteria induced more intensive NO production by macrophages and were more susceptible to bactericidal effect of mononuclear phagocytes than hemolytic mycobacterial strains. In contrast, the high-virulence hemolytic isolates induced significantly stronger TNF-alpha production by infected macrophages than the low-virulence unhemolytic bacilli.

Cellular reaction to Mycobacterium avium complex (MAC) clinical isolates differing in hemolytic activity and virulence for C57BL/6 mice

In this study we showed that Mycobacterium avium complex (MAC) clinical isolates differed by the expression of hemolytic activity. Two hemolytic MAC strains were less susceptible to the mycobactericidal effect of murine macrophages than two unhemolytic MAC isolates. In vivo, hemolytic MAC bacilli survived in the spleens of infected mice for a longer time than unhemolytic MAC strains. This suggested a role of hemolysins in the virulence of MAC strains. There was no difference in the cytotoxicity of T cells from mice immunized with M. bovis BCG towards macrophages infected in vitro with MAC strains expressing or not expressing hemolytic activity.