Mammalian cell invasion assays, using metacyclic trypomastigotes of Trypanosoma cruzi G and CL strains, showed that the CL strain enters target cells in several-fold higher numbers as compared with the G strain. Analysis of expression of surface glycoproteins in metacyclic forms of the two strains by iodination, immunoprecipitation and FACS, revealed that gp90, undetectable in the CL strain, is one of the major surface molecules in the G strain, that expression of gp82 is comparable in both strains and that gp35\50 is expressed at lower levels in the CL strain. Purified gp90 and gp35\50 bound more efficiently than gp82 to cultured HeLa cells. However, the intensity of the Ca# + response triggered in HeLa cells by gp82 was significantly higher than that induced by gp35\50 or gp90. Most of the Ca# + signalling

the characteristics of patients with cutaneous melanoma treated at Hospital São Paulo are similar to those found in the literature.