Résumé
Abstract We studied the involvement of lectin-like receptors in phagocytosis of unopsonized heat-killed yeast (Saccharomyces cerevisiae) by murine macrophagelike cell lines and murine peritoneal resident macrophages. For this purpose we used a technique that allowed us to discriminate ingested and adsorbed heat-killed yeast. The internalization can be partly inhibited by soluble polyosides such as laminarin (β-glucan) or a- mannan. However, when they were used together (0.4 mg/ml α-mannan and 0.4 mg/ml laminarin), almost complete inhibition of phagocytosis was obtained. These observations suggest that phagocytosis of unopsonized heat- killed yeast by murine macrophage-like cell lines as well as murine peritoneal resident macrophages is mediated by both mannose and β-glucan receptors. The respective activity of these two types of receptors is a function of in vitro cell differentiation. To achieve maximal phagocytosis of unopsonized heat-killed yeast, coexpression of both mannose and β-glucan receptors is required.