Suppressive effects of Hochu-ekki-to, a traditional Chinese medicine, on IgE production and histamine release in mice immunized with ovalbumin.

We examined the effects of Bu-Zhong-Yi-Qi-Tang (Japanese name: Hochu-ekki-to, HET), a traditional Chinese medicine, on IgE production and histamine release in mice immunized intraperitoneally with a mixture of ovalbumin (OA) and aluminum hydroxide (alum adjuvant). Three groups of mice were orally administered 0, 1.7 or 17 mg of HET on day 13 after the first immunization with a mixture of 1 microg OA and 1 mg alum adjuvant. They were again immunized with the same dose of OA plus alum adjuvant on day 14. The immunological changes in mice treated with OA alone or OA plus HET were examined, and the following findings were obtained. In the HET-treated mice, the elevation of anti-OA IgE in serum, and histamine release from basophils in blood, were significantly suppressed. A significant suppression of interleukin-4 (IL-4) secretion and proliferation of splenic lymphocytes in primary culture was also observed. A tendency to suppress the elevation of anti-OA IgG1 in serum and interleukin-2 (IL-2) secretion from splenic lymphocytes was observed in the HET-treated mice. These findings suggest that oral administration of HET suppresses IgE antibody production and histamine release in type I allergic reaction in mice immunized with OA plus alum adjuvant; this shows the efficacy of HET in treating type I allergic diseases, such as asthma.