Mammalian cell sialic acid enhances invasion by Trypanosoma cruzi.

We have used a Chinese hamster ovary cell mutant (Lec2) that express much less sialic acid on the surface than the parental cell line (Pro5) to investigate whether sialic acid plays a role during cell invasion by Trypanosoma cruzi. Trypomastigotes derived from a tissue culture (corresponding to bloodstream trypomastigotes) and metacyclic trypomastigotes (corresponding to infective stages of the insect vector) invaded the Lec2 mutant less efficiently than the parental cell line. Invasion of the Lec2 mutant cells could be restored to the Pro5 level by resialylation of the mutant cells with T. cruzi trans-sialidase and sialyllactose. Conversely, pretreatment of the Pro5 parental cells with bacterial neuraminidase decreased invasion. These results indicate that sialic acid associated with the host cell contributes to invasion by T. cruzi.