Immunoparasitological Studies of Trypanosoma Cruzi Low Virulence Clones from Panama: Humoral Immune Responses and Antigenic Cross‐Reactions with Trypanosoma Rangeli in Experimentally Infected Mice

Abstract

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.

Integrate Study of a Bolivian Population Infected by Trypanosoma cruzi, the Agent of Chagas Disease

“…These results and others definitively do not favor the common use of SAPA antigen for diagnosis of infection (lower sensitivity and specificity than conventional serology) neither for infection stage marker (among chronic patients 69% present anti-SAPA antibodies). Nevertheless, SAPA molecule may be used to discriminate patients with T. cruzi and T. rangeli infections as proposed , Saldana et al 1995.…”

Revisión de los aspectos biológicos y diagnósticos del Trypanosoma (Herpetosoma) rangeli

“…Recientemente, Saldaña et al 54 describieron, a través del análisis por inmunoblotting de epimastigotes del flagelado, un antígeno de T. rangeli de aproximadamente 43 kDa, que reacciona específicamente con sueros homólogos murinos hiperinmunes. Los autores afirman ser esta proteína un marcador específico del parásito.…”

Predominance of Trypanosoma rangeli infection in children from a Chagas disease endemic area in the west-shore of the Panama canal

“…The sensitivity and specificity of this assay is of 99.2 and 98%, respectively. Additionally, the positive sera were confirmed with an immunoblotting technique (reference test) with a crude epimastigote antigenic preparation derived from a Panamanian T. cruzi strain (Burunga) (Saldaña et al 1995). Positive (confirmed Panamanian case of Chagas disease) and negative (a healthy person from a non endemic area) control sera were used in each assay.…”