Cimetidine Enhances Antigen-Specific IgE and Th2 Cytokine Production

Treatment with anti-ulcer drugs has been shown to enhance IgE production against food antigens. However, little is known about the immunological effects of cimetidine, a histamine receptor type 2 (H2R) antagonist that is widely used as an anti-ulcer drug, in allergy. Therefore, the present study investigated the role of cimetidine in Th2 immune responses in mice. BALB/c mice were immunized intraperitoneally with ovalbumin (OVA) with and without cimetidine. The levels of cytokines in supernatants of spleen cells cultured in the presence of OVA for 4 days and the levels of total and OVA-specific IgG1, IgG2a and/or IgE in sera from these mice were determined by ELISA. Results: Administration of cimetidine to OVA-sensitized BALB/c mice promoted Th2 cytokine secretion by OVA-stimulated spleen cells in vitro and increased serum levels of OVA-specific IgE, IgG1 and IgG2a. Conclusions: These results indicate that cimetidine can enhance Th2 responses, suggesting that cimetidine may contribute to IgE production in allergies.