Abstract

This study was designed to evaluate the effects of oral administration of the extract from theRadix cyathula (RC) on the immune responses in mice immunized with ovalbumin (OVA). Forty-two Institute of Cancer Research (ICR) mice were randomly divided into six groups with seven animals in each group, and orally administered daily for 4 days at a dose equivalent to 0, 0.05, 0.1, 0.2, 0.4 and 0.8 g of the RC extract, respectively. After that, the mice were subcutaneously immunized twice with OVA at 2 weeks intervals. On day 14 after the second immunization, OVA-specific Immunoglobulin G (IgG) and the IgG subclasses, lymphocyte proliferation response, as well as interleukin-4 (IL-4) and interferon-gamma(IFN-γ) production were measured. Results indicated that the optical density (OD) value of OVA-specific IgG and the IgG subclass were significantly enhanced in mice orally administered RC at the dose of 0.2, 0.4 or 0.8 g, compared to the control group (p < 0.05). Besides, the splenocytes proliferation response and the production of IL-4 and IFN-γ were also significantly improved (p < 0.05) after the splenocytes were stimulated by OVA. In addition, the body weight of the mice administered with the RC extract (0, 0.1, 0.2, 0.4 and 0.8 g) was not significantly different compared to the mice administered saline. Collectively, the data suggested that RC extract could improve the immune response of vaccine through up-regulating the humoral immune response and the cellular immune response.

Key words: Radix cyathula, ovalbumin, adjuvant.