Macrophage membrane glycoproteins that bind Griffonia simplicifolia I-B4: effect on cytotoxicity and protein secretion.
Thioglycollate elicited peritoneal (TG-Møs) but not resident peritoneal Møs (R-Møs) were found to bind the lectin Griffonia simplicifolia isotype I-B4 (GSI-B4). This was demonstrated by ultrastructural studies and FACS analyses. Membranes from TG-Møs were isolated, separated on SDS-PAGE, electrotransferred onto nitrocellulose, and exposed to peroxidase-labeled GSI-B4. These procedures revealed two major membrane glycoproteins of molecular weights 180,000 and 94,000 daltons that bound the lectin GSI-B4 which has a specificity for recognizing terminal alpha-galactosyl residues. The presence of these epitopes on the two membrane glycoproteins was further substantiated by the fact that treatment of the membranes with alpha-galactosidase destroyed their capacity to bind GSI-B4 and that alpha-D-galactopyranoside but not N-acetyl-D-glucosamine competitively inhibited GSI-B4 from binding to the glycoproteins. Treatment of TG-Møs with GSI-B4 reduced the capacity of interferon (IFN) and lipopolysaccharide (LPS), or IFN alone, to induce Mø mediated cytotoxicity towards tumor cells by as much as 40%. GSI-B4 also caused alterations in the pattern of biosynthetically 35S-methionine labeled secreted proteins as early as 2 hours after contact with TG-Møs. Out of 35 discernible proteins on fluorograms of SDS-PAGE separated proteins, 5 were down-regulated and 9 were enhanced. It is suggested that the two novel Mø membrane proteins may play a role in regulating the response of Mø subpopulations to their humoral and cellular environments.
Warfel
A H
AH
Department of Medicine, New York University Medical Center, New York 10016.
Zucker-Franklin
D
D
Zheng
Z Y
ZY
D000818:Animals; D003602:Cytotoxicity, Immunologic; D004591:Electrophoresis, Polyacrylamide Gel; D005453:Fluorescence; D007372:Interferons / Q000494:pharmacology; D037102:Lectins / Q000378:metabolism*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D011506:Proteins / Q000378:metabolism*
D037102:Lectins; D008562:Membrane Glycoproteins; D011506:Proteins; D007372:Interferons