Protective effect of polysaccharides on simulated microgravity-induced functional inhibition of human NK cells

Carbohydr Polym. 2014 Jan 30;101:819-27. doi: 10.1016/j.carbpol.2013.10.021. Epub 2013 Oct 12.


Polysaccharides are believed to be strong immunostimulants that can promote the proliferation and activity of T cells, B cells, macrophages and natural killer (NK) cells. This study aimed to investigate the effects of five polysaccharides (Grifola frondosa polysaccharide (GFP), lentinan (LNT), G. lucidum polysaccharide (GLP), Lycium barbarum polysaccharide (LBP) and yeast glucan (YG)) on primary human NK cells under normal or simulated microgravity (SMG) conditions. Our results demonstrated that polysaccharides markedly promoted the cytotoxicity of NK cells by enhancing IFN-γ and perforin secretion and increasing the expression of the activating receptor NKp30 under normal conditions. Meanwhile polysaccharides can enhance NK cell function under SMG conditions by restoring the expression of the activating receptor NKG2D and reducing the early apoptosis and late apoptosis/necrosis. Moreover, the antibody neutralization test showed that CR3 may be the critical receptor involved in polysaccharides induced NK cells activation. These findings indicated that polysaccharides may be used as immune regulators to promote the health of the public and astronauts during space missions.

Keywords: Cytotoxicity; Human natural killer (NK) cell; Polysaccharide; Simulated microgravity (SMG).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Proliferation / drug effects
  • Humans
  • K562 Cells
  • Killer Cells, Natural / cytology*
  • Killer Cells, Natural / drug effects*
  • Killer Cells, Natural / immunology
  • Killer Cells, Natural / metabolism
  • Lymphocyte Activation / drug effects
  • Polysaccharides / pharmacology*
  • Receptors, Complement / metabolism
  • Signal Transduction / drug effects
  • Weightlessness Simulation / adverse effects*


  • Polysaccharides
  • Receptors, Complement