Th2 polarizing helminth infection alters the immune response to an oral Salmonella-OVA vaccine (41.5)

Abstract

Abstract We have previously shown that enteric helminth infection acts as a mucosal adjuvant, priming for a Th2 biased response to soluble ovalbumin (OVA), a tolerogenic form of dietary antigen. An immunogenic response to orally administered OVA can be elicited by administration of OVA in the context of an oral vaccine. To examine whether chronic enteric infection can also influence the efficacy of oral vaccination we examined the response to a novel OVA-expressing oral Salmonella vaccine (Salmonella-OVA; Smith et al submitted) in both infected and non-infected mice. This live attenuated vaccine induces a Th1 biased mucosal and systemic OVA specific response. Infection of C57Bl/6 mice with the helminthic parasite Heligmosomoides polygyrus delayed and reduced the Th1 dependent serum OVA specific IgG2c response induced by two doses of oral vaccine. By contrast, helminth infection enhanced the Th2 dependent serum OVA specific IgG1 response. Helminth infection also altered mucosal and systemic OVA specific cytokine and chemokine responses. These data suggest that concomitant enteric helminth infection can significantly alter the immune response to oral vaccination. Since chronic enteric parasitic infections are endemic in much of the developing world, our observations have important implications for the testing and development of mucosal vaccines. This work was supported by NIH grants DK 55678 and DK43551 and predoctoral training fellowships 5F31AI054229-05 and T32 A107529.