Cellular Interactions of Murine Immune Cells Exposed to Live Mycobacterium intracellulare, Its Whole Lipid Extract, and Its Serovar-Specific Glycopeptidolipid

In this study we examined some of the immunological responses to Mycobacterium intracellulare and its lipid components. Our results indicate that infection with M. intracellulare can increase the expression of adhesion molecules, ICAM-1 and LFA-1, only at the site of injection (peritoneum). There was no change in the expression of these adhesion molecules in the lymphoid organs (thymus and spleen). Significant increases in the adhesion molecules were observed in the spleen cells incubated with the lipid derived from mycobacteria in the presence of concanavalin (Con A) compared to the Con A alone. The expression of the Thy 1.2 and Lyt-2 markers was not affected by the bacteria or their lipids. The results indicate a marked increase in the mitogenic response by the infected spleen cells removed at an early day. The blastogenic study also indicated that the lipids can reduce the mitogen-induced blastogenesis of spleen cells removed from M. intracellular- and saline-injected mice; moreover, they suggested that the spleen cells removed from Listeria monocytogens-infected mice can also be affected by mycobacterial lipids. This indicates a nonspecific effect by these lipids. The results that the immunological response was contingent upon prior exposure of the mice to M. intracellulare, and also was dependent on whether the cells came from the peritoneal cavity or lymphoid organs.