DISTRIBUTION OF EPITOPES OF TRYPANOSOMA-CRUZI AMASTIGOTES DURING THE INTRACELLULAR LIFE-CYCLE WITHIN MAMMALIAN-CELLS

In this study we have examined the distribution of epitopes defined by monoclonal antibodies raised against Trypanosoma cruzi amastigotes du ring the intracellular life cycle of the parasite. We have raised mono clonal antibodies towards amastigote forms and performed preliminary i mmunochemical characterization of their reactivities. MAB 1D9, 3G8, 2B 7, 3B9, and 4B9 react with carbohydrate epitopes of the parasite major surface glycoprotein-Ssp-4 defined by MAB 2C2 [5]; MAB 4B5 reacts wit h a noncarbohydrate epitope in all developmental stages of the parasit e, and MAB 3B2 also detects a noncarbohydrate epitope preferentially i n T. cruzi flagellated forms. Vero cells infected with tissue culture- derived trypomastigotes of clone D11 (G strain) were fixed at differen t times during the intracellular proliferation of parasites, and proce ssed for immune-electron microscopy and confocal immunofluorescence wi th the different monoclonal antibodies. We observed that while the sur face distribution of MAB 2C2 and 4B9 epitopes was uniform throughout t he cycle, MAB 1D9, 3G8, and 2B7 reacted with cytoplasmic membrane-boun d compartments of the amastigotes. MAB 3B9 displayed a unique surface dentate pattern in some amastigotes. MAB 4B5 recognized a curved-shape d structure at the flagellar pocket region in some intracellular amast igotes and localized to the membrane in dividing forms. In intracellul ar trypomastigotes, MAB 4B5 also displayed a punctate pattern near the flagellar pocket.