Macrophage inhibitory factor-A3 derived from Mycobacterium avium serovar 2 inhibits candidacidal activity of murine peritoneal macrophages.

Macrophage inhibitory factor-A3 (MIF-A3), a fraction derived from Mycobacterium avium serovar 2 inhibited candidacidal activity in macrophages from C57BL/6, C57BL/10, C3H/HeJ and A/J strains of mice. Inhibition of candidacidal activity was demonstrated at MIF-A3 concentrations ranging from 100-400 micrograms/ml in macrophages without additional stimulators (exception C3H/HeJ macrophages) and in macrophages additionally stimulated with 200 U/ml interferon-gamma, 100 ng/ml phorbol myristate acetate and 0.4 ng/ml E. coli lipopolysaccharide from all mouse strains tested. The decreased candidacidal effect produced by MIF-A3 was dose-dependent and appeared greatest in macrophages treated with phorbol myristate acetate and lipopolysaccharide. This effect was neutralized by the addition of goat anti-MIF-A3 antiserum. Macrophages from the Bcgs mouse strains (C57BL/6 and C57Bl/100 were more sensitive to the effect(s) of MIF-A3 than macrophages from the Bcgr mouse strains (C3H/HeJ and A/J).