PURIFICATION OF A 74-KILODALTON SURFACE GLYCOPROTEIN FROM HEART MYOBLASTS THAT INHIBITS BINDING AND ENTRY OF TRYPANOSOMA-CRUZI INTO HEART-CELLS

We have identified and purified a 74 kDa surface glycoprotein from hea rt myoblasts that specifically binds to Trypanosoma cruzi trypomastigo tes, and inhibits the attachment and internalization of trypomastigote s into these cells. The native form of the 74 kDa glycoprotein was pur ified to apparent homogeneity by preparative scale isoelectrofocusing and anion exchange chromatography. Pre-incubation of trypomastigotes w ith soluble 74 kDa glycoprotein strongly inhibited the binding and int ernalization of trypomastigotes into heart myoblast monolayers in a co ncentration dependent-manner. Pre-incubation of heart myoblast monolay ers with antibodies specific to the purified 74 kDa glycoprotein also strongly inhibited trypomastigote binding and internalization into hea rt cells in a concentration dependent manner. These results support th e notion that the surface 74 kDa glycoprotein is a target molecule on heart myoblast cells to which T. cruzi binds in order to invade them.