Free Bile Acids Inhibit IgE Production by Mouse Spleen Lymphocytes Stimulated by Lipopolysaccharide and Interleukins

Abstract

The interaction of IL-4, IL-5, and free bile acids with the immunoglobulin production by mouse spleen lymphocytes was studied to examine their immunoregulatory activity. In the absence of lipopolysaccharide (LPS), IL-4 enhanced the IgE and IgG production significantly and the IgA production weakly, but not the IgM production. On the other hand, IL-5 had an inhibitory tendency on the IgE and IgA production, though not significantly. In the presence of LPS, both IL-4 and IL-5 significantly enhanced the IgE production by mouse splenic lymphocytes. When the lymphocytes were cultured with the physiological concentration of free bile acids (10 microM) and LPS for 3 days, chenodeoxycholic acid inhibited the IgE production, but cholic and deoxycholic acids did not. In the presence of IL-4 or IL-5, these bile acids cancelled the stimulatory effects of interleukins and rather significantly inhibited the IgE production. These results suggest that these free bile acids act as an anti-allergic agent.