Antimycobacterial effect of lysates prepared from immunologically activated macrophages

Abstract

Lysates or heptane extracts of peritoneal (P) and alveolar (A) normal macrophages (N-M), immune macrophages (I-M), and immune-activated macrophages (IA-M) were examined for antimycobacterial activity by the agar-plate diffusion test. This test has been found suitable to reveal the antibacterial activity in 3-day incubated, but not in freshly prepared, lysates. Results showed that materials of IA-AM or I-AM and of IA-PM exerted antimycobacterial effects, whereas materials of N-PM, I-PM, and of N-AM were usually inactive. Antimycobacterial activity of lysates of AM was stronger than that of PM. The formation of antibacterial factors during an incubation of M lysates, the solubility of the factors in heptane, and various other characteristics suggested that the antimycobacterial effect was caused by the formation of toxic levels of non-esterified fatty acids. M lysates exerted equal activities against BCG, H(37)Ra, and H(37)Rv strains of tubercle bacilli. The presence of antimycobacterial activity in lysates prepared from IA-M of either BCG- or BCG-sensitized animals indicated that the potential to generate antimycobacterial activity is associated with the state of delayed hypersensitivity and the state of activation of M.