Involvement of the major glycoprotein (gp43) of Paracoccidioides brasiliensis in attachment to macrophages

The yeast form of Paracoccidioides brasiliensis, the causative agent of a d eep mycosis in humans, is known to be phagocytized by, and to multiply insi de, macrophages. In this work we describe the involvement of gp43, a major antigenic protein of P. brasiliensis, in the initial steps of attachment of the fungus to macrophages. Anti-gp43 F(ab) polyclonal fragments were capab le of inhibiting phagocytosis in a concentration-dependent manner. Sheep re d blood cells sensitized with purified gp43 were more endocytized than SF:B C alone, and this process was also inhibited by anti-gp43 F(ab) fragments. Inhibition tests indicated the involvement of fucose and mannose residues i n the phagocytosis of the fungus and of SRBC-gp43 by macrophages. Taken tog ether, these results suggest that gp43 may be involved in the adherence and uptake of the fungus by murine peritoneal macrophages, and that this bindi ng may be dependent on monosaccharide residues that are part of the gp43 gl ycoprotein.