Expression of a mannosyl-fucosyl receptor for endocytosis on cultured primary macrophages and their hybrids.

Abstract

The presence of a pinocytosis receptor, specific for mannose-fucose terminated glycoprotein, was established on murine resident peritoneal macrophages, thioglycollate-elicited peritoneal macrophages and macrophages derived from bone-marrow in culture. Macrophage-like cell lines (J-774 [mouse neoplastic] and P338.D1 [mouse leukemia]), a myelomonocytic cell line (427E), lymphocytes, polymorphonuclear leukocytes and fibroblasts were negative. Binding and uptake of 125I-mannose-BSA [bovine serum albumin] and 125I-.beta.-glucuronidase, respectively, into thioglycollate-induced peritoneal macrophages was saturable .**GRAPHIC**. = 5.4 .times. 10-9 M; .**GRAPHIC**. = 7 .times. 10=7 M) and sugar-specific. Macrophage-macrophage (rat .times. mouse) hybrids prepared by fusing rat alveolar macrophages with J-774-B10 (HAT [hypoxanthine-aminopterine-thymidine]-sensitive macrophage-like cell line) expressed the mannose-fucose receptor. Karyotypes of the hybrids confirmed a 1:1 fusion of rat and mouse cells. The rat/mouse hybrids expressed a variety of rat and mouse antigens including Fc receptors. Fibroblast-macrophage hybrids and melanoma-macrophage hybrids were negative for mannose-fucose receptor activity. The expression of the mannose-fucose receptor by macrophages appears to be regulated independently of other macrophage markers.