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Stimulation of human macrophages in vitro by cereal beta-glucans and related polymers. R. G.
FULCHER, J. L. Causey, and J. L. Slavin. Department of Food Science and Nutrition, University of
Minnesota, St. Paul, Minnesota, 55108.
Cereal beta-glucans were long thought to be passive biological
polymers, eliciting their effects in humans primarily through viscosity modifications in the gut. We report
here a modified role for beta-glucans: human immune stimulation and modified gut fermentation. Human
monocytes, macrophages and neutrophils glucan receptors on their surfaces. Immune cells use these
lectin-like receptors to recognize the beta-(1-3)-glucan component of bacterial, yeast and fungal cell walls and
subsequently engulf and destroy these potential invaders. We have developed a cell culture system to study
the effects of mixed-linkage cereal cell wall beta-glucans on human-derived white blood cells, specifically
the monocyte/macrophage lineage. Highly purified, mixed linkage oat and barley beta-glucans of differing
concentration and molecular weight were applied to cells in culture. A 6-fold increase in macrophages was
observed with 100 micrograms/ml high molecular weight oat beta-glucan, while a 7.5-fold increase was
noted at an equivalent concentration of low molecular weight oat beta-glucan. Low molecular weight barley
beta-glucan was 3 times more stimulatory than a polymer-free basal medium. Additionally, we have applied
commercially available mannans and xylans to cells and found a 9-fold and 5-fold increase in macrophages,
respectively. Our results indicate a significant role for cereal cell wall polymers: activation of a portion of
the human immune system.
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