Serum from infected mice suppresses macrophage-mediated immunity in Mycobacterium lepraemurium infection: a model for imparied macrophage immunity in human leprosy.

Differing patterns of Mycobacterium lepraemurium infection in inbred strains of mice are of interest as a model system for studying mycobacterial infections of man, e.g. M. leprae, which present with a spectrum of clinical disease. In vitro, macrophages from both resistant (C57B1) and susceptible (BALB/c) inbred strains of mice can be shown to be equally effective in controlling multiplication of M. lepraemurium. Experiments presented here show that in vivo, the potential mechanisms of macrophage-mediated immunity are suppressed in the susceptible (BALB/c) strain of mouse by a soluble factor(s) present in the serum and the peritoneal fluid of infected mice.