GASTRIC INVASION BY TRYPANOSOMA-CRUZI AND INDUCTION OF PROTECTIVE MUCOSAL IMMUNE-RESPONSES

Trypanosoma cruzi is an intracellular parasite transmitted from a redu viid insect vector to humans by exposure of mucosal surfaces to infect ed insect excreta. We have used an owl challenge murine model that mim ics vector-borne transmission to study T. cruzi mucosal infection, Alt hough gastric secretions have microbicidal activity against most infec tious pathogens, we demonstrate that T, cruzi can invade and replicate in the gastric mucosal epithelium. In addition, gastric mucosal invas ion appears to be the unique portal of entry for systemic T. cruzi inf ection after oral challenge, The mucosal immune responses stimulated b y T, cruzi gastric infection are protective against a secondary mucosa l parasite challenge, This protective mucosal immunity is associated w ith increased numbers of lymphocytes that secrete parasite-specific im munoglobulin A, Our results document the first example of systemic mic robial invasion through gastric mucose and suggest the feasibility of a mucosal vaccine designed to prevent infection with this important hu man pathogen.