A monoclonal antibody to Trypanosoma cruzi trypomastigotes recognizes a myosin tail epitope

A monoclonal antibody, 1E7, raised against tissue culture-derived trypomastigotes of Trypanosoma cruzi reacted with proteins located at the perinuclear region of the parasite as detected by immunofluorescence and immunogold electron microscopy. The antibody also recognized antigens in all trypanosomatids tested, including T. cruzi epimastigotes, as well as in many mammalian cells. Five principal antigens of 140-270 kDa soluble in 1 M NaCl were recognized by the monoclonal antibody, suggesting that the epitope may belong to more than one polypeptide since the same bands appeared even when the samples were treated with high concentrations of denaturing agents. The antibody reacted in Western blots with muscle myosin. Bacterial clones expressing fast skeletal muscle myosin head or tail cDNAs upon IPTG induction were used to demonstrate that 1E7 monoclonal antibody recognizes an epitope present in the tail region of the myosin heavy chain. This result adds to the on-going discussion related to the possible existence of an auto-immune component in the immunopathogenesis of Chagas' disease due to cross-reactive epitopes shared by the parasite and cardiac myosin.