Abstract
We evaluated the effect of treatment of mice with concanavalin-A (Con-A) on the phagocytosis of glutaraldehyde-fixed Candida albicans by peritoneal macrophages. The mean number of unopsonized C. albicans blastoconidia phagocytosed in vitro by peritoneal macrophages was doubled (from 1.3±0.1 to 2.7±0.14) by pre-treatment of the donor mice with Con-A. The percent of peritoneal cells phagocytosing the blastoconidia in vitro was increased about four times (from 22.3±8.6 to 80.3±3.2) by Con-A. This increase in phagocytosis was about 50% inhibited by addition of mannan (50 μg) plus mannose (50 mM) to the assay medium, suggesting that it was mediated by mannose receptors (MR). Phagocytosis in vitro in the presence of fresh non-immune serum (5%) was also increased, from 84.3±5.0 for untreated macrophages to 100% for Con-A activated peritoneal macrophages and the mean number of opsonized C. albicans blastoconidia increased from 2.3±0.1 to 4.6±0.1. These results suggest that treatment of mice with Con-A increased both the phagocytosis of C. albicans blastoconidia mediated by mannose receptors and by complement receptors.