The polypeptide profiles of strains of the Trypanosoma subgenera Schizotrypanum and Trypanozoon: peptideme characterization

TRYPANOSOMA SAIMIRII RODHAIN, A JUNIOR SYNONYM OF TRYPANOSOMA RANGELI TEJERA

In the present study, we used sodium dodecyl sulfate-polyacrylamide gel electrophoresis to compare polypeptides of trypanosomes isolated by hemoculture of squirrel monkeys displaying Trypanosoma saimirii blood trypomastigotes, with other trypanosomes that infect primates to evaluate the validity of T. saimirii. The polypeptide profiles of trypanosomes isolated directly from squirrel monkeys or after their passage in mice were identical to those of 3 standard strains of T. rangeli, but they were distinct from those of T. cruzi, T. conorhini, and T. minasense. These results strengthen previous morphological and biological findings by Rodhain on trypanosomes of the squirrel monkey and lead to the conclusion that T. saimirii is indeed a junior synonym of T. rangeli.

Immunoparasitological studies of Trypanosoma cruzi low virulence clones from Panama: humoral immune responses and antigenic cross-reactions with Trypanosoma rangeli in experimentally infected mice

The kinetics of humoral immune responses were investigated in mice experimentally infected with five clones of Trypanosoma cruzi isolated from different sources in Panama. Sera were collected at different timepoints post-infection. ELISA and IHA tests were used to detect antibodies against T. cruzi epimastigote antigens. The levels of T. cruzi specific antibodies increased during the course of infection; at day 90 post-infection the range was between 1:5120 and 1:10240. A high correlation was evident between ELISA and IHA results. Western blots revealed that these antibodies recognized polypeptides of 81, 76 and 71 KDa during the first weeks and 81, 76, 71, 50, 40, 28 and 12 KDa after 30-50 days. Only minor differences in antigen recognition patterns were demonstrated, suggesting that the major antigens may be represented in all clones. T. rangeli antigens were also recognized by T. cruzi seropositive sera. However, an ELISA test using antigens isolated from a genomic expression library of T. cruzi revealed that a hyperimmune rabbit serum against T. rangeli was unable to recognize the repeat sequence of SAPA (Shed Acute Phase Antigen) peptides but did recognize a number of other T. cruzi synthetic peptide antigens. The importance of these findings, in the context of Chagas' disease, is discussed.

Trypanosoma cruzi: polypeptide markers of epimastigotes and trypomastigotes

We compared the major polypeptides of epimastigotes and trypomastigotes of T. cruzi, by submitting total parasite lysates to electrophoresis in polyacrylamide gels (SDS-PAGE), protein staining with Coomassie brilliant blue, laser densitometry, or immunoblotting with sera derived from infected individuals (Chagas' disease). Epimastigotes and trypomastigotes displayed extensive homology, the differences being quantitative, except for a trypomastigote-specific band of Mr 75,000 which reacted with chagasic sera. Immunoblotting with chagasic sera confirmed the electrophoretic homology of epimastigotes and trypomastigotes. Upon antigenic dilution, a cluster of antigenic bands in the range of Mr 150,000 to 75,000 prevailed in the trypomastigotes, whereas the epimastigotes displayed more abundance of antigenic bands in the range of Mr 72,000 to 36,000.

Identification and analysis of epimastigote surface and metabolic proteins in Trypanosoma cruzi

Metabolic and surface membrane proteins of four epimastigote-stage Trypanosoma cruzi clones were analyzed by one and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No major inter-clonal differences were observed in the metabolic protein patterns, indicating that these proteins are highly conserved. However, marked quantitative and qualitative differences were observed in surface-labeled protein patterns following both one and two-dimensional electrophoretic analyses. Inter and intra-clonal differences in antigenic properties also were demonstrated by immunoprecipitation of the surface proteins with sera from animals immunized or infected with various T. cruzi stocks. Thus, a wide spectrum of both phenotypic and antigenic diversity exists in T. cruzi which may be relevant to problems of the diagnosis and immunotherapy of Chagas' disease.