Protective effects of hochu-ekki-to, a Chinese traditional herbal medicineagainst murine cytomegalovirus infection

The innate immunity against murine cytomegalovirus (MCMV) at the early phas e of infection is mediated by NK cells and macrophages. We studied the effe cts of hochu-ekki-to (HET), a traditional Chinese herbal medicine, on the r egulation of innate immunity mediated by NK cells and macrophages. We found the oral administration of HET to increase both the number of leukocytes i n the spleen and liver and the splenic NK cell cytotoxicity associated with the increased induction of serum IFN-alpha/beta after an MCMV infection bu t it had no effect on liver NK cells. However, no differences were found in the serum IL-12, IFN-gamma, TNF-alpha and nitric oxide (NO) production in the culture of macrophages between the HET- and PBS-treated mice on day 2 a fter MCMV infection. In addition, MET-treated splenic and peritoneal macrop hages were found to show a higher intrinsic resistance against in vitro MCM V infection than that of PBS-treated mice. Therefore, the MET-induced effec ts on NK cells and macrophages selectively reduced the viral load in the sp leen but not in the Liver at an early phase of MCMV infection. HET may thus be useful in the treatment of human cytomegalovirus infection which common ly occurs in HIV-infected AIDS patients. (C) 1999 Elsevier Science B.V. All rights reserved.