The effects of carboxymethyl chitosan on the regulation of the proliferation, differentiation and cytokine expression of peripheral blood mononuclear cells

To elucidate the effects of carboxymethyl chitosan (CMCTS) on the proliferation, differentiation and cytokine secretion of peripheral blood mononuclear cells (PBMCs), leukomonocytes were separated and cultured. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, acridine orange/ethidium bromide staining, flow cytometry and enzyme-linked immuno sorbent assay was used to evaluate different concentrations of CMCTS A (molecular weight (MW)=50 000) and CMCTS B (MW=500 000) in the proliferation, apoptosis, differentiation and cytokine secretion of PBMCs. The results demonstrated that CMCTS A and CMCTS B at concentrations of 500 and 100 μg ml−1, respectively, significantly enhanced the proliferation of PBMCs. Both CMCTS A and CMCTS B inhibited the apoptosis of PBMCs, and the optimal inhibitory concentration was 500 μg ml−1. Furthermore, the inhibitory efficacy of CMCTS A was higher than that of CMCTS B. CMCTS A induced the differentiation of PBMCs with CD4 antibody at concentrations of 500 and 100 μg ml−1. Furthermore, the differentiation of PBMCs with CD3–CD56 antibodies was induced by both CMCTS A and CMCTS B. Both CMCTS A and CMCTS B at concentrations of 500 μg ml−1 induced interleukin (IL)-2 secretion, with CMCTS A having a more marked effect than that of CMCTS B. CMCTS A at a concentration of 500 μg ml−1 induced interferon (IFN)-γ secretion. In conclusion, CMCTS with a low MW (50 000) and at a concentration of 500 μg ml−1 positively regulated the proliferation, differentiation and IFN-γ and IL-2 secretion of the PBMCs in vitro.