Organization and expression of a multigene family encoding the surface glycoproteins of Trypanosoma cruzi metacyclic trypomastigotes involved in the cell invasion.

The infective forms of Trypanosoma cruzi are the trypomastigote stages found in the bloodstream of mammalian hosts or the metacyclic trypomastigotes present in the digestive tract of the insect. Metacyclic trypomastigotes express two stage-specific glycoproteins (gp90 and gp82) that have no counterpart in blood trypomastigotes (Yoshida 1983, Teixeira & Yoshida 1986). The gp90 and gp82 are involved in the penetration of the parasite into host cells (Araguth et al. 1988, Yoshida et al. 1993, Ramirez et al. 1993, Santori et al. 1996a). Gp82 can induce Ca2+ signal in target cells (Dorta et al. 1995, Ruiz et al. 1998), an event essential for T. cruzi internalization (Dorta et al. 1995). Gp90 and gp82 are also relevant immunologically. Immunization with gp90 or gp82 protects mice against acute infection by T. cruzi (Araguth et al. 1988, Gonzalez et al. 1991, Yoshida et al. 1993, Santori et al. 1996b). Here we present studies on the genomic organization and expression of genes encoding gp90 and gp82.