Correlation of tunicamycin-sensitive surface glycoproteins from Trypanosoma cruzi with parasite interiorization into mammalian cells.

Trypomastigote forms of Trypanosoma cruzi lose infectivity to cultured mammalian cells when exposed to tunicamycin. Upon reincubation into fresh medium, parasites recover their full penetration capacity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of [35S]methionine-labeled polypeptides showed that tunicamycin-treated parasites present several components with altered electrophoretic mobility when compared with controls. Immunoprecipitation with rabbit hyperimmune and human chagasic sera indicated that the surface antigens of approximate molecular masses of 175-180, 120-125, 90-95 and 85 kDa are not encountered in tunicamycin-treated trypomastigotes. By affinity chromatography on wheat germ agglutinin-Sepharose, it was observed that the trypomastigote-specific 85 kDa glycoprotein (Tc-85) is affected by the drug. The other affected components are glycoproteins with affinity for concanavalin A. The results suggest that tunicamycin-sensitive surface glycoproteins from T. cruzi are involved in the parasite interiorization into mammalian cells.