Structural characterization and immune regulation of a novel polysaccharide from Maerkang Lactarius deliciosus Gray

The present study investigated the structural characterization and immune regulation of a novel polysaccharide from Maerkang Lactarius deliciosus Gray. Chemical methods, high performance gel permeation chromatography, fourier transform infrared spectroscopy, nuclear magnetic resonance spectrum and gas chromatography‑mass spectrometry were used to characterize the polysaccharide structure. The immunomodulatory abilities of the Maerkang L. deliciosus Gray polysaccharide (LDG‑M) were also investigated. LDG‑M was primarily composed of β‑D‑glucose and α‑D‑lyxose with the ratio of 2:1. The possible structure of LDG‑M had a backbone of 1,6‑linked‑β‑D‑glucose and 1,4,6‑linked‑β‑D‑glucose, with branches primarily composed of one (1→4)‑linked‑α‑D‑lyxose residue. The immunoregulatory activity results demonstrated that LDG‑M promoted the proliferation and phagocytosis of macrophages, and induced cytokine release. LDG‑M also promoted the proliferation of B cells by affecting the G0/G1, S and G2/M phases. The present study introduced LDG‑M as a valuable source with unique immunoregulatory properties.