FIG. 4.

T. cruzi-specific Th1 cells, but not Th2 cells, inhibit intracellular parasite replication in infected macrophages. PEM cultured in tissue culture slide chambers were infected with T. cruzi trypomastigotes. Parasite-specific Th1 cells, Th2 cells, or no T cells were added, and these cultures were incubated for 48 h prior to harvesting supernatants for measurements of IFN-γ (A) and NO (B) production. The percentages of T. cruzi-infected macrophages and the average numbers of intracellular AMA per infected cell were determined microscopically (C). The effects of added T cells on T. cruzi infection are expressed as the percent inhibition compared with results for macrophages infected in the absence of T cells. Shown are the means (± standard errors) from replicate cultures. Similar results were seen in multiple experiments.