Carbohydrate-bearing cell surface receptors involved in innate immunity: Interleukin-12 induction by mitogenic and nonmitogenic lectins

Based on the observation that pathogen-derived lectins play an important ro le in cell adhesion and invasion, we examined the possible role of host car bohydrate-bearing molecules in inducing the secretion of IL-12, a crucial p roinflammatory cytokine. The ability of 12 plant lectins to recognize and s timulate naive murine mononuclear cells in vitro has been characterized in this study. Mitogenic lectins (comprising Con A, PHA, PSA and LCA) were fou nd to induce the secretion of multiple cytokines in vitro, including IL-2, interferon (IFN)-gamma, and IL-12. Of interest, WGA, a nonmitogenic lectin unable to promote IL-2 secretion, was found to induce IL-12 and IFN-gamma p roduction in a T and B cell-independent fashion. The functional properties of WGA were inhibited by N-acetylneuraminic acid and N,N'-diacetylchitobios e. WGA therefore represents a potentially useful tool for the study of memb rane glycoproteins involved in the early proinflammatory response character istic of innate immunity. (C) 1999 Academic Press.