In vitro Assessment of Polysaccharides Immunoregulatory Effects on CD3+CD56+ NKT-like Cells

Aims: Polysaccharides have shown efficacy in a broad range of applications, especially in immune regulation. However, there are only few effective methods available to evaluate and compare the immunoregulatory properties of the different polysaccharides in vitro. To screen stringently and extend the fields of application of polysaccharide-based treatments, a novel in vitro method, based on the use of cord blood-derived CD3+CD56+ NKT-like cells, was developed in this study.

Methodology: Four injectable polysaccharides used in clinics, including Lentinan (LNT), Bacillus Calmette-Guerin polysaccharide nucleic acids (BCG-PSN), ginseng polysaccharides (GPS), and Shengfu polysaccharides (SFPS), which all might benefit cancer therapy, were further validated by testing their effect on cell proliferation and cytotoxicity in vitro. This new evaluation system could discriminate the effects of the four polysaccharides.

Results: Cells treated for 4 days with either of the four polysaccharides were fewer than untreated cells. Upon 7-day treatments, plant- or bacteria-derived BCG-PSN, GPS, and SFPS induced higher level of IFN-, proportion of cells with a CD3+CD56+ phenotype, and cytolytic activity toward A549 cells, compared to controls. However, fungus-derived LNT yielded lower IFN-, proportion of CD3+CD56+ cells, and cytolytic activity than control conditions.Additionally, all four polysaccharides, in decreasing order GPS, SFPS, BCG-PSN, and LNT, induced significantly higher concentrations of TNF-α compared to control, with respectively.

Conclusion:Cord blood-derived CD3+CD56+ NKT-like cells may represent a powerful tool to screen and evaluate the immunoregulatory potential of biological or chemical compounds for clinical developments and applications.