Immunomodulatory properties of oat and barley β-glucan populations on bone marrow derived dendritic cells

Specific structures of oat and barley β(1,3)(1,4)-glucans induced different in vitro immunomodulatory effects in bone marrow derived dendritic cells (BMDC) from TLR2/4 knock out mice. All barley β-glucan fractions induced larger amounts of cytokines in BMDCs than their oat equivalents. The particulate fractions of both glucans induced high amounts of cytokines, especially after sample homogenisation. The small particulate barley β-glucans induced more cytokines than the equivalent oat fraction, hence there are more features influencing the immunomodulatory properties of β-glucans than only the particle size. The soluble glucan fraction and heated suspension induced only low amounts of cytokines, but were different for the two β-glucans, indicating that molecular specificity matters for immunomodulation. Immunomodulatory activity is influenced by the insolubility of β-glucans, to which characteristics as particle size, granule conformation and particulate homogeneity are related. Consequently, sample preparation influences the immunomodulatory activity of β-glucans.