Purification and characterization of stage-specific glycoproteins from Trypanosoma cruzi

Four developmentally regulated glycoproteins were purified from detergent solubilized cell membranes of Trypanosoma cruzi. Three trypomastigote specific glycoproteins each migrated as single bands under denaturing conditions with approximate Mr of 90,000, 85,000, and 55,000 and pI values of 4.3-5.0, 8.5-9.1, and 8.2, respectively. The fourth, epimastigote specific, protein had an approximate Mr of 72,000 and a pI of 4.8-5.1. The Mr of all four glycoproteins changed by 5-50% upon endoglycosidase F treatment. The Mr 72,000 antigen was the only one that reacted strongly with anti-epimastigote sera raised in rabbits. Sera from a Chagasic patient reacted strongly with the three trypomastigote specific glycoproteins and very weakly with the Mr 72,000 glycoprotein.