Juzen-taiho-to, a Japanese herbal medicine, modulates type 1 and type 2 T cell responses in old BALB/c mice.

Aging is associated with skewed type 2 (T2) T cell responses that may be modulated by herbal medicines. A group of Japanese herbal medicines, so-called "Hozai," have been used to improve the physical condition of the elderly. One representative "Hozai," Juzen-Taiho-To (JTX) appears to have beneficial effects on cancer patients. In this study we hypothesized that JTX modulated skewed T2 responses in the elderly. T1 and T2 responses against ovalbumin (OVA) were examined in old BALB/c mice fed JTX (0.2% w/w). We measured anti-OVA IgG1, IgG2a, and IgG2b antibody (Ab) levels after the primary and secondary OVA challenges; T1 and T2 responses augment IgG2a/IgG2b Ab and IgG1/IgE Ab production, respectively. We also assessed production of T1 and T2 cytokines (IFN-gamma and IL-5, respectively), and co-stimulatory molecule expression by regional draining lymph node cells. JTX-fed mice had higher IgG2b Ab and IFN-gamma production than controls along with lower IgG1 Ab. JTX did not alter IL-5 production or co-stimulatory molecule expression. Hoelen, an herbal component, induced similar changes. Our results indicate that JTX and Hoelen modulate T cell responses against OVA toward more balanced T1/T2 responses in old BALB/c mice. Such effects of JTX may help prevent the development of diseases associated with immunodisregulation in the elderly.