Rui Zhao^*, Guiyan Jia, Yongzhong Yu, Bocui Song, Chao Hu and Lingyu Wu

Previous study has showed that portulaca oleracea L. polysaccharide (POL-P3b), possess adjuvant activity. In the process of immune response, dendritic cells (DC) play a significant role. In view of this, DC maturation and enhancing function were investigated by oral administration with POL-P3b, as an adjuvant for foot-and-mouth disease (FMD) vaccine. The mechanisms involved were further identified. We found that administration with POL-P3b at different concentrations induced DC maturation by increasing co-stimulatory and MHC-II expression. Furthermore, POL-P3b improved stimulus activity of T lymphocyte, and the high dose was more pronounced. In addition, POL-P3b polarized cytokine secretion toward the Th1 pathway. Interestingly, the content of mitochondrial membrane potential was significantly increased in DC+POL-P3b group. To clarify the mechanisms, the effects of POL-P3b on TLR4 signaling pathways were further investigated. Our results showed that POL-P3b treatment increased TLR4 expression and decreased the expression of caspase-3, -9 and -8. On the whole, the experimental results suggested that POL-P3b could be used as an effective adjuvant for FMD vaccine by inducing maturation and enhancing function of DCs, and the mechanism was related to regulating TLR4 signaling pathway.

To Cite This Article: Zhao R, Jia G, Yu Y, Song B, Hu C and Wu L, 2020. Regulating activity of polysaccharides from portulaca oleracea L. on dendritic cells of mice immunized against foot-and-mouth disease. Pak Vet J, 40(1): 7-12. http://dx.doi.org/10.29261/pakvetj/2018.126