Increased levels of antibodies to IFN-gamma in human and experimental African trypanosomiasis.

In African trypanosomiasis the occurrence of antibodies to interferon-gamma (IFN-gamma) was studied in both humans and experimental rats. Sera from patients infected with Trypanosoma brucei gambiense showed increased levels of antibodies to IFN-gamma as compared with controls from the same regions in Africa. In Sprague-Dawley rats infected with Trypanosoma brucei brucei an early appearance of IFN-gamma-producing spleen cells was observed, followed by an increase in levels of antibodies against IFN-gamma in the sera. Previously, IFN-gamma has been found to play a crucial role in trypanosome infections in rats by promoting proliferation of Trypanosoma brucei brucei. The appearance of antibodies to IFN-gamma in humans, as in rats, indicates that this cytokine is produced also in the human infection. Its parasitic growth-stimulating and pathophysiological effects on the organism may be reduced by the antibodies.