Use of parasite antigens and interleukin-2 to enhance suppressed immune responses during Trypanosoma cruzi infection in mice.
Mice infected with Trypanosoma cruzi exhibit an early and profound suppression of parasite-specific and nonspecific immune responses. Earlier studies have shown that this suppression is due, at least in part, to suppressor macrophages, deficiency in production of interleukin-2 (IL-2), and reduced T helper (Th)-cell activity. In the present study, the effect of exogenously supplied IL-2 on enhancement of parasite-specific Th-cell activity, anti-parasite immunoglobulin G (IgG) and IgM antibody levels, parasitemia, and longevity was examined in infected mice. The results showed that administration of IL-2 with and without antigenic stimulation with trinitrophenylated T. cruzi significantly enhanced parasite-specific IgM and IgG levels. Injection of IL-2 and trinitrophenylated T. cruzi together significantly enhanced parasite-specific Th-cell activity and was more effective in enhancement of parasite-specific antibody levels. In addition, it was found that IL-2 alone had a rapid and lasting effect in reducing parasitemia. These results suggest that deficiency in IL-2 may play a major role in host susceptibility to T. cruzi.
D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000276:immunology*; D014355:Chagas Disease / Q000276:immunology*; D005260:Female; D007108:Immune Tolerance; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007376:Interleukin-2 / Q000008:administration & dosage*; D051379:Mice; D008809:Mice, Inbred C3H; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology; D014349:Trypanosoma cruzi / Q000276:immunology*
D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007376:Interleukin-2; D014301:Trinitrobenzenes