Tissue macrophages of calves after high doses of glucan.

Relatively high doses of the soluble form of fungal glucan (50 mg/kg of body weight) were administered to two clinically healthy calves. Hepatosplenomegaly was not observed. Quantitative and significant qualitative changes were seen in macrophages in the medulla of lymph nodes as compared to the control animals. Both the fibrillar and the granular components in the vacuoles of phagocytosing cells appeared to be positive in the periodic acid-Schiff reaction (PAS); an amorphous component was PAS negative. Quantitative changes occurred also in the expression of IgM molecules on the surface of B lymphocytes. The results indicate that glucan can be used in ruminants also in a single high dose.