2. University of Louisville, Department of Pathology, Louisville, KY, USA.
Background: Yeast was the first microorganism used as a source of protein and it still is the main source of unicellular protein in human nutrition. Numerous yeast products and yeast derivatives are produced and used in animal feed, pet food, and human food around the world. Although the whole yeast cell and the yeast cell wall have β-1,3-1,6-glucan in their chemical composition, their immunological effects in vivo can be quite different of those of the yeast purified β-1,3-1,6-glucan.
Methods: In order to study these different in vivo effects, we used a traditional package for evaluation of commercial glucans to compare the whole yeast cell, the yeast autolysate, the yeast cell wall, and the yeast purified β-1,3-1,6-glucan produced from the same original yeast raw material. We evaluated the effects of these compounds on phagocytosis, IL-2 secretion, and antibody production.
Results: We found that although the whole yeast cell and the yeast cell wall have β-1,3-1,6-glucan in their chemical composition, their immunological effects in vivo can be quite different of those of the yeast purified β-1,3-1,6-glucan.All activities, ie., phagocytosis, IL-2 production and antibody production were the highest in the group supplemented with purified glucan.
Conclusions: Our results suggest that the yeast derivatives have more limited immunological effects, maybe as a result of local intestinal immune reactions. The purified glucan showed stronger immunological activities.
Keywords: Autolysis, biologically active polysaccharides, glucans, yeast cell wall and yeast derivatives