Research in our laboratories is focused on the roles played by intestinal epithelial cells in the secretory immune response to enteric pathogens. One of our goals is to generate and characterize specific IgA antibodies that can prevent interaction of pathogens with epithelial surfaces. It is now generally recognized that microorganisms and macromolecules that can adhere to epithelial cells are most effective in eliciting specific secretory IgA antibodies^1,2, presumably because adherent immunogens are most efficiently endocytosed and transported across the epithelium. Adherence to the M cells of follicle-associated epithelia is probably crucial in this regard, since transepithelial delivery of antigens by these cells may be a prerequisite for a mucosal immune response^3–5.