title: Degranulation of polymorphonuclear leukocytes is induced by multivalent cross-linking of wheat germ agglutinin binding site(s) on cell membrane.
abstract: Polymorphonuclear leukocyte (PMN) surface membrane glycoproteins very likely are involved in the phenomenon of stimulus-response coupling. Previously, we have shown that subagglutinating concentrations of the plant lectin, wheat germ agglutinin (WGA) specifically and irreversibly inhibited N-formyl-methionyl-leucyl-phenyl-alanine (FMLP)-mediated PMN chemotaxis. WGA did not affect the binding of [3H]FMLP to its receptor on the PMN plasma membrane. We have examined the possibility that cross-linking of WGA binding sites may elicit PMN degranulation. We have found that multivalent, but not bivalent, cross-linking of WGA bound to PMNs elicits release of lysosomal constituents. This phenomenon was specific for WGA since it did not occur when concanavalin A (Con A), instead of WGA, was used. It is intriguing to speculate that WGA may attach to a "physiologic" receptor for FMLP on the PMN membrane and that redistribution (cross-linking) of this receptor might be an early event in the activation of PMNs by FMLP.
mesh_terms: D000328:Adult; D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D005966:Glucuronidase / Q000378:metabolism; D006098:Granulocytes / Q000378:metabolism*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D037102:Lectins / Q000276:immunology*; D009113:Muramidase / Q000378:metabolism; D037121:Plant Lectins; D014908:Triticum
chemical_list: D003432:Cross-Linking Reagents; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D037102:Lectins; D037121:Plant Lectins; D009113:Muramidase; D005966:Glucuronidase