Granulomatous inflammation during Heligmosomoides polygyrus primary infections in FVB mice.

Host responses to primary infections with Heligmosomoides polygyrus were studied in fast responding FVB mice (H-2(q)). Pathological changes in the intestinal mucosa, mesenteric lymph nodes and spleen were examined. Features of the fast response were typical: low effectiveness of infection and limiting of parasite survival and egg production, with worm expulsion occurring about 60 days post-infection. The intestinal inflammatory response involved infiltration by different cells into the intestinal mucosa and granulomata formation. As is typical for intestinal nematode infection enteropathy, decreased villus:crypt ratio and hyperplasia of goblet and Paneth cells were also present. Reactions of the intestinal mucosa, mesenteric lymph nodes and spleen increased over time post-infection and after worm expulsion. Enteropathy may help worm expulsion by creating an unfavourable environment for H. polygyrus. The implications of these findings and the potential role of intestinal intraepithelial lymphocytes in the pathogenesis of generated lesions are discussed.