Experimental African trypanosomiasis: Differences in cytokine and nitric oxide production by macrophages from resistant and susceptible mice

Immunosuppression in experimental infections with Trypanosoma congolense is mediated by the synergistic action of macrophages and a novel lymphocyte(s ), which involves the activity of IFN-gamma as well as IL-10. BALB/c mice a re highly susceptible while C57BI/6 mice are relatively resistant to T, con golense infections. Plasma and/or supernatants of spleen cell cultures of i nfected susceptible BALB/c mice have more IL-10 but less IL-12 than those o f infected relatively resistant C57B1/6 mice. Cells of a BALB/c macrophage cell line, when pulsed with T. congolense, produce more IL-10 and IL-6, but have less TNF-alpha mRNA, than equal ly treated cells of a C57B1/6 cell li ne. Peritoneal and/or bone marrow-derived macrophages obtained from BALB/c mice, pulsed with T. congolense in culture, produce less nitric oxide, TNF- alpha and IL-12, but more IL-6 and IL-10 than equally treated macrophages i solated from C57B1/6 mice. We suggest that genetic resistance to African tr ypanosomiasis is expressed at the level of the macrophage. Copyright (C) 20 00 S. Karger AG, Basel.