Copyright © 1997, American Society for Microbiology Invasion of Intestinal Epithelia In Vitro by the Parasitic Nematode Trichinella spiralis

Studies of nematode establishment in intestinal niches has been hindered by the lack of a readily manip-ulated in vitro assay. In this report, experiments are described wherein the larval stage of the parasitic nematode Trichinella spiralis was shown to invade epithelial cell monolayers in vitro. Larvae penetrated cells and migrated through them, leaving trails of dead cells in their wake. Cells derived from five different species were susceptible to invasion, reflecting the broad host range of T. spiralis in vivo. Epithelial cells derived from large and small intestines and kidneys were susceptible. Fibroblast and muscle cells were resistant. Larvae deposited glycoprotein antigens in the cells they invaded. Although the function of these antigens is unknown, they are targeted by rat antibodies that cause T. spiralis to be expelled from the intestine. The model system described provides the means to further investigate this process as well as the mechanisms by which this parasitic nematode establishes its intestinal niche. Trichinella spiralis is a parasitic nematode that initiates in-fection in the small intestine of its vertebrate host. The larval and adult stages of T. spiralis are found in the intestinal epi-thelium, often at the crypt-villus junction, and do not appear to cross the basement membrane. Despite its relatively large size