Phagocytosis of yeast by Biomphalaria glabrata: carbohydrate specificity of hemocyte receptors and a plasma opsonin

• Published in: Developmental and comparative immunology Vol. 13; no. 1; p. 9
• Main Authors: Fryer, S E, Hull, C J, Bayne, C J
• Format: Journal Article
• Language: English
• Published: United States 1989
• Subjects: Animals; Biomphalaria - immunology; Biomphalaria - parasitology; Carbohydrates - immunology; Glucans; Glycogen - immunology; Hemocytes - immunology; Mannans - immunology; Opsonin Proteins; Phagocytosis; Polysaccharides - immunology; Receptors, Immunologic; Saccharomyces cerevisiae - immunology; Schistosoma mansoni - immunology
• ISSN: 0145-305X
• DOI: 10.1016/0145-305X(89)90011-6

In vitro phagocytosis of yeast cells by hemocytes of the mollusc Biomphalaria glabrata can occur in the absence of plasma, but is enhanced by opsonization in plasma from certain snail strains. We have investigated the carbohydrate specificity of the hemocyte-bound receptor for phagocytosis and the free plasma opsonin using two dominant carbohydrate components of the yeast cell wall (laminarin and mannan). Phagocytic uptake in the absence of plasma of both untreated and opsonized yeast is strongly inhibited by laminarin, but is unaffected by mannan. In contrast, laminarin does not interfere with opsonization whereas mannan blocks the process, blocking the binding of a 57 kD plasma component as detected by Western immunoblot. These results suggest that the opsonic lectin in plasma is not simply a free form of the hemocyte-bound receptor for yeast phagocytosis.