Trypanosoma cruzi-induced tyrosine phosphorylation in murine peritoneal macrophages.

Trypanosoma cruzi, the etiological agent of Chagas' disease, binds to and invades macrophages and other cells (fibroblasts, muscle cells) via a complicated set of interactions, but the changes induced by parasite-to-cell interactions are largely unknown. This report investigates the ability of T. cruzi to elicit a tyrosine kinase pathway in immature and mature resident murine peritoneal macrophages (MPM) that differ in their susceptibility to parasite infection. T. cruzi stimulated the phosphorylation of tyrosine residues in several endogenous substrates (proteins of 40-42, 53-56, 66, 75, 80, 90, 95, 100, and 112 kDa), but only in immature MPM. Mature MPM had high levels of spontaneous tyrosine phosphorylation. Upstream tyrosine kinases, such as src-like tyrosine kinases, were not responsible for the differential patterns of tyrosine phosphorylation since they were present in both mature and immature MPM. We suggest that the tyrosine phosphorylation patterns stimulated by T. cruzi reflect most of the biochemical events that occur in parasite host-cell interactions.