Structural characterization, immunomodulatory effect and immune-mediated antitumor activity of a novel polysaccharide from the rhizome of Atractylodis macrocephala Koidz oleh Yu Zhuang, Xiao-Yu Huan, Long Sun, Wang Wang, Meng-Juan Zhou, Ming Zhao, Pei-Dong Chen, Hui Yan, Peng Pang, Xu-Qin Shi, Ren-Jie Xu, Gui-Sheng Zhou, Shu-Lan Su