Effect of lipopolysaccharide on the induction of tolerance to polymerized flagellin

The effect of bacterial lipopolysaccharide (LPS) on the induction of tolerance to the T-independent polymerized flagellar protein (POL) of Salmonella adelaide strain SW1338 was studied in vitro. In contrast to published results with T-dependent antigens, LPS failed to prevent or reverse tolerance induction to POL under conditions in which tolerance was reversible by other means. Moreover, the addition of high doses of LPS to slightly supra-immunogenic concentrations of POL augmented-tolerance induction. These results suggest that the mitogenic properties of LPS are insufficient to convert a tolerogenic dose of POL into an immunogenic one and, therefore, that LPS may act only on T-dependent B cell responses. Since both POL (1338) and LPS are T-independent, mitogenic and so-called "polyclonal B cell activators," these data have implications for signal discrimination in the immune response.