Mechanisms of Parasite Antigen Uptake from the Intestine of Rats Infected with the Nematode Nippostrongylus brasiliensis.

The mechanisms of antigen-uptake at the host mucosal barrier during infection with lumen-dwelling intestinal parasites have not been well elucidated. In this study, we investigated immunolocalization of parasite excretory/secretory (ES) products in the small intestinal epithelium of rats infected with Nippostrongylus brasiliensis. Immunoelectronmicroscopy revealed intense ES immunoreactivity in the absorptive cell cytoplasm in association with lysosome-associated membrane glycoprotein (LAMP-1), and in the paracellular spaces. These results indicated that nematode antigen could be absorbed by two pathways : absorption by endocytosis and transport to lysosomes, and absorption through the paracellular pathway, suggesting altered mucosal barrier function.