Nocardia rubra cell-wall skeleton promotes CD4⁺ T cell activation and drives Th1 immune response

Several lines of evidences have shown that Nocardia rubra cell wall skeleton (Nr-CWS) has immunoregulatory and anti-tumor activities. However, there is no information about the effect of Nr-CWS on CD4⁺ T cells. The aim of this study was to explore the effect of Nr-CWS on the phenotype and function of CD4⁺ T cells. Our results of in vitro experiments showed that Nr-CWS could significantly up-regulate the expression of CD69 and CD25 on CD4⁺ T cells, promote the proliferation of CD4⁺ T cells, increase the production of IFN-γ, TNF-α and IL-2 in the supernatants, but has no significant effect on the apoptosis and death of CD4⁺ T cells. Results of in vivo experiments showed that Nr-CWS could promote the proliferation of CD4⁺ T cells, and increase the production of IL-2, IFN-γ and TNF-α (Th1 type cytokines). These data suggest that Nr-CWS can enhance the activation of CD4⁺ T cells, promote the proliferation of CD4⁺ T cells and the differentiation of CD4⁺ T cells to Th1 cells.