Immunity due to immune balance contributes to disease prevention and treatment. Radix Codonopsis polysaccharide (RCP) is isolated from the root of the Chinese herb Codonopsis pilosula. Previous studies have indicated that RCP has immunomodulatory activities; however, the effects of RCP on immunity, especially immune balance, are still largely unknown. In the present study, we investigated the effects of RCP on T-cell balance in mice. The mice were pretreated intragastrically with or without RCP for 15 days and injected with hydrocortisone on days 10-15 to disturb the immune system. The spleen and thymus were weighed and used to calculate immune organ indexes. The percentages of CD4⁺ T cells, CD8⁺ T cells, Th1 cells, Th2 cells, regulatory T cells (Tregs) and Th17 cells in peripheral blood were assayed by flow cytometry. Pro-inflammatory and anti-inflammatory cytokines, TNF-α, IL-1β and IL-10, in serum were determined by enzyme-linked immunosorbent assay (ELISA) kits. The results showed that RCP pretreatment could maintain the homeostasis of CD8⁺ T cells, Tregs, Th17 cells, TNF-α, IL-1β and IL-10 in hydrocortisone-treated mice. Furthermore, RCP pretreatment maintained the immune balance of CD4⁺/CD8⁺ T cells, Th1/Th2 cells, Tregs/Th17 cells, IL-10/TNF-α and IL-10/IL-1β. Taken together, RCP pretreatment had beneficial effects on the maintenance of T-cell balance against hydrocortisone disturbance in mice and potential to be developed into novel functional food.

Lycium barbarum polysaccharide (LBP) is isolated from the fruit of Chinese herbal Lycium barbarum. Previous studies had demonstrated that LBP could inhibit tumor growth and enhance the immunity in mice. However, the effect of LBP on systemic and local immune responses in vivo, especially on phenotypic and functional changes of T cells, is still largely unknown. In the present study, we investigated the effects of LBP on systemic and local T cell-dependent antitumor immune responses in H22 tumor-bearing mice. The results showed that LBP could inhibit the solid tumor growth in mice, but showed little effect on the body weight or spleen index. Furthermore, LBP could maintain high levels of T cells in peripheral blood (PB), tumor draining lymph node (TDLN), and tumor tissue, prevent the increase of Tregs while promote infiltration of CD8⁺ T cells in tumor tissue, inhibit the production of TGF-β1 and IL-10 in serum, decrease the exhaustion phenotype of T cells, and maintain cytotoxicity of lymphocytes. Taken together, our results demonstrated that LBP simultaneously induced systemic and local immune responses in H22 tumor-bearing mice by alleviating immunosuppression and maintaining antitumor immune responses in mice.