Trypanosoma cruzi suppresses the expression of the p75 chain of interleukin-2 receptors on the surface of activated helper and cytotoxic human lymphocytes.
When Trypanosoma cruzi is co-cultured with activated human lymphocytes the latter manifest a marked level of suppression in their capacity to express high-affinity interleukin-2 receptors (IL-2R). In this study we asked whether this effect could result from reduced expression of the p75 component of the IL-2R, a condition which would limit the number of heterodimeric receptors that could be assembled by activated T cells. The results of two-colour flow cytometric analyses revealed that both the percentage and surface density of p75 molecules on phytohaemagglutinin-stimulated CD3+, CD4+ or CD8+ lymphocytes were significantly reduced in the presence of T. cruzi, whether or not the parasites were separated from the lymphocytes by a cell-impermeable filter. These results suggested that reduced expression of p75 chains would limit the number of IL-2R assembled by activated T lymphocytes, contributing in this manner to the immunosuppression that occurs during acute T. cruzi infection.
Kierszenbaum
F
F
Department of Microbiology and Public Health, Michigan State University, East Lansing 48824.
Sztein
M B
MB
D015703:Antigens, CD / Q000032:analysis; D014355:Chagas Disease / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D015703:Antigens, CD; D015375:Receptors, Interleukin-2