SELECTIVE NEUTRALIZATION BY ANTI-INTERFERON GLOBULIN OF MACROPHAGE ACTIVATION BY L-CELL INTERFERON, BRUCELLA-ABORTUS ETHER EXTRACT, SALMONELLA-TYPHIMURIUM LIPOPOLYSACCHARIDE, AND POLYANIONS

Addition of interferon (IF) inducers pyran copolymer, poly(I)-poly(C), an ether extract of Brucella abortus (Bru-Pel), or Salmonella typhimurium lipopolysaccharide (LPS) to cultures of peritoneal macrophages in vitro enhanced their cytotoxic activity for MBL-2 lymphoblastic leukemia cells. To evaluate the role of induced IF in the macrophage activation, highly specific rabbit anti-L-cell IF globulin was added to resting macrophage cultures at the same time as the macrophage-activating agents. Macrophage activation by these various biological and synthetic agents was totally neutralized by anti-IF globulin but not by normal rabbit globulin. Similarly, the anti-IF globulin inhibited the ability of chromatography-purified Newcastle disease virus-induced IF to render macrophages cytotoxic, and the degree of neutralization of IF titer corresponded with the inhibition of IF-induced macrophage-mediated cytotoxicity. In contrast, macrophage activation by concanavalin A-induced lymphokine, which contains an antigenically different IF, was not affected by high titers of the anti-L-cell IF antibodies. The results indicate that endogenously generated type I IF may play an important role in control of macrophage function. © 1979.