Specific glycoprotein antigens on the surface of insect and mammalian stages of Trypanosoma cruzi.

Abstract

Two major surface antigens on T. cruzi, the causative agent of [human] Chagas disease, have been described [Nogueira et al (1981)]. One, a 75,000 MW glycoprotein (GP), is specific for the culture forms (insect-host stages) of the organisms-epimastigotes and metacyclic tryptomastigotes. The other 90,000 MW GP, was found in vertebrate-host stages of the organisms-bloodstream-form trypomastigotes. These 2 major surface antigens of T. cruzi seem to be unrelated proteins, as judged by tryptic and chymotryptic peptide analysis. Antibodies were raised in rabbits against epimastigotes or trypomastigote proteins which had been immunoprecipitated with human antisera. These trypomastigote and epimastigote protein antisera reacted only with the homologous immunogen, as determined by immunoprecipitation of surface-labeled organisms and by immunofluorescence. The 75,000 MW GP is detected only in cultured (insect stage) epimastigotes and metacyclic trypomastigotes. The 90,000 MW GP is only present in bloodstream-form trypomastigotes, amastigotes and trypomastigotes obtained from infected muscle cells in vitro. The insect and vertebrate stages of this species display distinctive surface GP that can be identified by surface labeling and immunoprecipitation techniques in 6 strains of T. cruzi (Y, CL, Peru, Colombiana, SF-12 and SF-21) isolated from widely different areas of South America.