Detection of an "epimastigote-like" intracellular stage of Trypanosoma cruzi.

Monoclonal antibody (mAb) DION 5.1b, derived from mice immunized with Trypanosoma dionisii, recognizes a 72/76-kD surface glycoprotein specific to the epimastigote stage of T. dionisii and T. cruzi. None of the three other stages of the T. cruzi life cycle expresses any DION 5.1b-specific epitope. However, mAb DION 5.1b labels an intracellular form with "epimastigote-like" morphology that appears to be late and transient in the intracellular cycle. This result suggests that the morphological similarity between the observed "epimastigote-like" intracellular form in mammals and the epimastigote form in insects may extent to the antigenic pattern.