Cereal β-glucan preparations of different weight average molecular weights induce variable cytokine secretion in human intestinal epithelial cell lines

The immune-modulating properties of fungal β-glucans have long been known, but also the structurally different cereal β-glucans have been ascribed immune-modulating properties. Since molecular weight is a crucial factor for the activity of fungal β-glucans, we investigated the effects of cereal β-glucans with different weight average molecular weights ( M ¯ w ) on two human intestinal epithelial cell lines (Caco-2 and HT-29) by monitoring cytokine secretion. Cereal β-glucan of low M ¯ w (40 kDa) increased IL-8 secretion by HT-29 cells significantly, whilst cereal β-glucans of higher M ¯ w (123–359 kDa) showed little effect on IL-8 secretion. The effect of 40 kDa cereal β-glucan on IL-8 secretion by HT-29 cells was both dose and time dependent and not due to LPS contamination. These results suggest that a number of dietary β-glucans may directly interact with some intestinal epithelial cells, resulting in moderately increased IL-8 secretion by these cells.