Increased Levels of Antibodies to IFN‐γ in Human and Experimental African Trypanosomiasis

Abstract

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.

Human and rodent interferon‐γ as a growth factor for Trypanosoma brucei

“…First human rIFN-y stimulated growth of strains of 7: gambiense and 7: rhodesiense recently isolated from human patients in the present study. We have recently reported the occurrence of anti-IFN-y antibodies in humans infected with 7: gumbiense which indicates that this cytokine is also produced in humans during trypanosome infection [27] and a preliminary analysis of cytokines in patients affected by African trypanosomiasis showed a selective and significant variation of only IFN-y with the severity of the disease [28]. In support of this finding, suramin, which has been in use for many decades for clinical treatment of early stages of trypanosome infections, has recently been shown to be a powerful suppressor of IFN-y production ~9 1 .…”

Adipose Tissue: A Safe Haven for Parasites?

“…The passage of T. brucei parasites into the brain is facilitated by the presence of a number of components of the immune system (such as interferon γ (IFNγ)) [31,34]. IFN-γ is abundantly expressed during a T. brucei infection and it promotes parasite growth [35]. However, there are no experimental data at this point substantiating if parasite entry into the brain and other tissues shares similar features.…”

Immunobiology of African Trypanosomiasis

“…Given the potential significance of macrophage activation in trypanosomiasis, it is logical to turn to the nature of the macrophage-activating factor(s), at least one of which is likely to be IFN-, the synthesis of which is significantly up-regulated following infection with African trypanosomes in humans [42] and experimental rodents [43][44][45].…”