Infection of tissue culture cells with bloodstream trypomastigotes of Trypanosoma cruzi.

Infection of tissue culture ("Vero" and bovine embryo skeletal muscle cells) with bloodstream from of T. cruzi depends on an adequate serum concentration and a suitable parasite population. The percentages of infections of "Vero" cells obtained with inocula presenting about 90% (Y strain) and 2% (CL strain) of slender trypomastigotes wree 11.8 +/- 4.9% and 0.1%, respectively, strongly indicating that the presence of slender forms was essential for cell infection to occur. Nevertheless, other biological characteristics seem to influence the infectivity of bloodstream stages, because evidence was provided that slender forms of the CL strain were less infective to "Vero" and muscle cells that slender forms of the Y strain.