Type II arabinogalactan from Anoectochilus formosanus induced dendritic cell maturation through TLR2 and TLR4

Phytomedicine. 2015 Dec 15;22(14):1207-14. doi: 10.1016/j.phymed.2015.10.010. Epub 2015 Nov 10.

Abstract

Background: Polysaccharides, considered as immunomodulators with the capacity to activate immunity against microbial pathogens and tumors, have been employed for their dietary and medical benefits.

Purpose: This study investigated the immunomodulatory effect of polysaccharide such as type II arabinogalactan from Anoectochilus formosanus (AGAF) on dendritic cell (DC) maturation and the underlying molecular mechanisms.

Methods and results: Exposing DCs to AGAF induces cell maturation, which is characterized by the upregulation of CD86, CD83, CD80, CD40, and MHC class I and class II expression through flow cytometry analysis and morphological change without cytotoxicity. In addition, AGAF-triggered DC2.4 cells were involved in priming T-cell activation in vitro and in vivo. Transfection of toll-like receptor (TLR) 2 proteins and TLR4 siRNA suppressed DC maturation, suggesting that AGAF induced DC maturation through TLR2 and TLR4.

Conclusion: These findings indicate that AGAF may be a potentially effective immunomodulator in stimulating DC maturation.

Keywords: Anoectochilus formosanus; Arabinogalactan; D.C2.4 cells; DC maturation; Polysaccharides; T cell activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / drug effects
  • Cell Line
  • Dendritic Cells / cytology
  • Dendritic Cells / drug effects*
  • Galactans / pharmacology*
  • Lymphocyte Activation*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Orchidaceae / chemistry*
  • RNA Interference
  • T-Lymphocytes / cytology
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism*
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism*

Substances

  • Galactans
  • Tlr2 protein, mouse
  • Tlr4 protein, mouse
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • arabinogalactan