Suppressor factor of T-cell activation and decreased interleukin 2 activity in experimental African trypanosomiasis.
Spleen cells from Trypanosoma brucei-infected BALB/c mice were unable to respond to a T-cell mitogen, concanavalin A. Moreover, they were unable to produce detectable amounts of the growth factor required for T cell proliferation, interleukin 2. In addition, supernatants from 24-h in vitro cultures of these cells produced a slight but detectable suppressive activity of the interleukin 2-dependent proliferation of a T-cell line. Infected spleen cells also suppressed the response of T. brucei-immunized spleen cells as well as normal spleen cells to concanavalin A. However, a major difference was shown in the mechanism of the suppression in both systems. Suppression of normal spleen cells required cell-to-cell contact. In contrast, suppression of 30-day T. brucei-immune cells could be mediated by a soluble suppressor factor released by in vitro culture of infected spleen cells. This molecule had an apparent molecular weight of 18,000. Finally, similar suppression could be generated in 30-day T. brucei-immune spleen cells but not in normal cells, with living cells but not with extracts of T. brucei.
D000818:Animals; D003208:Concanavalin A; D007376:Interleukin-2 / Q000032:analysis*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D012016:Reference Values; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014346:Trypanosoma brucei brucei / Q000276:immunology; D014353:Trypanosomiasis, African / Q000276:immunology*
D007376:Interleukin-2; D003208:Concanavalin A