Growth of Mycobacterium lepraemurium in nonstimulated and stimulated mouse peritoneal-derived and bone marrrow-derived macrophages in vitro.

Mycobacterium lepraemurium cells were found to multiply in normal mouse peritoneal-derived and bone marrow-derived macrophages in vitro. Whereas activated peritoneal-derived macrophages demonstrated marked bacteriostasis for M. lepraemurium, significant bactericidal activity was exhibited by activated bone marrow-derived macrophages. However, only a small proportion of the bacterial were killed by activated bone marrow-derived macrophages with subsequent and enhanced bacteria growth. It is suggested that a rapid turnover of monocytes in active lesions is required to control mycobacterial infections in vivo. These results would suggest that careful consideration be given to the choice of the host cell in studies involving obligate intracellular parasites.