Carboxymethylation enhances the maturation-inducing activity in dendritic cells of polysaccharide from the seeds of Plantago asiatica L.

- Carboxymethylated PLCP enhances the expression of surface molecules of DCs.
- Carboxymethylated PLCP enhances the stimulatory capacity of MLR of DCs.
- Carboxymethylated PLCP stimulates the secretion of IL-12p70 cytokine of DCs.
- Carboxymethylated PLCP induces the mRNA synthesis of chemokine receptors of DCs.
- Carboxymethylated polysaccharides can be used as immunotherapeutic adjuvant.

Carboxymethylation is a well-known modification process for polysaccharides. To evaluate the biological availability of carboxymethyl, polysaccharide from the seeds of Plantago asiatica L. (PLCP) was carboxymethylated (CM-PLCP) and the immunomodulatory activities of five CM-PLCPs of gradient degree of substitution (DS) from 0.40 to 0.62 were determined on dendritic cells (DCs) in vitro. Compared with DCs treated with PLCP, DCs treated with CM-PLCP of DS0.50, DS0.55, DS0.62, as well as CD86 and CD80, expressed higher levels of MHCII, CD86 and CD80 surface molecules. In addition, the secretion of IL-12p70 and the mRNA of CCR7 and CXCR4 chemokines were increased, while the endocytosis activities were inhibited. Correspondingly, stronger mixed lymphocyte reactions were induced by the DCs treated with the CM-PLCPs. The results showed that carboxymethylation modification of relevant high DS can enhance the DC maturation-inducing function of PLCP, indicating the potential application of carboxymethylated polysaccharide as an immunotherapeutic adjuvant.