Efficacy of Kakkon-To, a Traditional Herbal Medicine, Against Herpes Simplex Virus Type 1 and Influenza Infection in Mice

This chapter focuses on the action of Kakkon-to in herpes simplex virus (HSV) and influenza infections using experimental infection systems in mice. It uses a cutaneous HSV type 1 (HSV-1) infection model in mice as an experimental model for human viral infection, and demonstrated the therapeutic efficacy of Kakkon-to treatment. Since the delayed-type hypersensitivity (DTH) response has been reported to be a major host defense system in intradermal HSV-1 infection, the chapter focuses on the DTH reaction and various factors related to the natural defense system against HSV-1 infection. It then discusses the finding that the induction of the strong DTH reaction to HSV-1 antigen plays a major role in the treatment of cutaneous HSV-1 infection with Kakkon-to. It also adopts an intranasal influenza virus infection model in mice to evaluate the therapeutic efficacy of Kakkon-to. This murine model is very useful for characterizing the development of typical pneumonia with pathologic changes similar to those in humans.