Characterization of the infective properties of a new genetic group of Trypanosoma cruzi associated with bats.

A new genotype of Trypanosoma cruzi, associated with bats from anthropic areas, was recently described. Here we characterized a T. cruzi strain from this new genetic group, which could be a potential source of infection to humans. Metacyclic trypomastigotes (MT) of this strain, herein designated BAT, were compared to MT of well characterized CL and G strains, as regards the surface profile and infectivity toward human epithelial HeLa cells. BAT strain MT expressed gp82, the surface molecule recognized by monoclonal antibody 3F6 and known to promote CL strain invasion by inducing lysosomal exocytosis, as well as mucin-like molecules, but lacked gp90, which functions as a negative regulator of invasion in G strain. A set of experiments indicated that BAT strain internalization is gp82-mediated, and requires the activation of host cell phosphatidylinositol 3-kinase, protein kinase C and the mammalian target of rapamycin. MT of BAT strain were able to migrate through a gastric mucin layer, a property associated with p82 and relevant for oral infection. Gp82 was found to be a highly conserved molecule. Analysis of the BAT strain gp82 domain, containing the cell binding- and gastric mucin-binding sites, showed 91 and 93% sequence identity with G and CL strains, respectively. Hela cell invasion by BAT strain MT was inhibited by purified mucin-like molecules, which were shown to affect lysosome exocytosis required for MT internalization. Although MT of BAT strain infected host cells in vitro, they were less effective than G or CL strains in infecting mice either orally or intraperitoneally.