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 role in cell adhesion and invasion, we examined the possible role of host carbohydrate-bearing molecules in inducing the secretion of IL-12, a crucial proinflammatory cytokine. The ability of 12 plant lectins to recognize and stimulate naive murine mononuclear cells in vitro has been characterized in this study. Mitogenic lectins (comprising Con A, PHA, PSA, and LCA) were found 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 production in a T and B cell-independent fashion. The functional properties of WGA were inhibited by N-acetylneuraminic acid and N,N'-diacetylchitobiose. WGA therefore represents a potentially useful tool for the study of membrane glycoproteins involved in the early proinflammatory response characteristic of innate immunity. Copyright 1999 Academic Press.