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Structural characterization of a pectin-type polysaccharide from Curcuma kwangsiensis and its effects on reversing MDSC-mediated T cell suppression

Dong, Cai-Xia, Zhang, Wen-Sheng, Sun, Qi-Li, Jiang, Yun-Jia, Fu, Zheng, Zhang, Ying, Du, Juan, Sun, Yuan-Xia, Tao, Ning, Yao, Zhi
International journal of biological macromolecules 2018 v.115 pp. 1233-1240
CD8-positive T-lymphocytes, Curcuma kwangsiensis, Fourier transform infrared spectroscopy, adaptive immunity, gas chromatography-mass spectrometry, gel chromatography, hosts, immunosuppression, molecular weight, nuclear magnetic resonance spectroscopy, polysaccharides, suppressor cells, therapeutics
Myeloid-derived suppressor cells (MDSCs) accumulate in tumor-bearing hosts and play a major role in tumor-induced immunosuppression. The potent modulatory effects of polysaccharides on the innate and adaptive immune system stimulate antitumor responses. In this study, a polysaccharide with an apparent molecular weight of 14.0 kD was isolated from Curcuma kwangsiensis and designated as CKAP-2. The polysaccharide was characterized through high-performance gel permeation chromatography, chemical derivative analyses, GC–MS, FT–IR, and NMR. Results revealed that CKAP-2 is a highly methyl-esterified pectin-type polysaccharide. It is predominantly composed of a homogalacturonan region and small amounts of type-I rhamonogalacturonan regions. Its degree of methyl-esterification is approximately 62.4%. The effect of CKAP-2 on MDSC-medicated immunosuppression was primarily tested. CKAP-2 recovered the MSC2-supressed proliferation of CD4+ and CD8+ T-cells. This finding suggested that CKAP-2 can reverse MDSC-mediated T-cell suppression and that CKAP-2 can be potentially applied in antitumor therapy.