| Abstract: | A nonagglutinating derivative of wheat germ agglutinin (WGA), prepared by treating the native lectin with cyanogen bromide and formic acid and purified by affinity chromatography on an N-acetyl-D-glucosamine column, inhibited human polymorphonuclear leukocyte (PMN) chemotaxis to the synthetic chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). The WGA derivative (WGA-D) did not influence either the ability of PMN to migrate randomly or their chemotactic response to the complement-derived peptide C5a. Similarly, WGA-D had no effect on either FMLP-induced PMN polarization or other FMLP-induced PMN functions (i.e., selective discharge of lysosomal enzymes from cytochalasin B-treated cells, generation of superoxide anion). The inhibition of FMLP-induced PMN chemotaxis by WGA-D could not be reversed by washing the cells, or by incubating lectin-treated PMN at 37 degrees C for 20 min. The inhibitory effect of WGA-D was mediated by its specific binding to N-acetyl-D-glucosamine residues on the cell surface. WGA-D did not alter the specific binding of 3H]-FMLP to its receptor(s) on the PMN membrane. The data presented here suggest that WGA-D inhibits FMLP-induced PMN chemotaxis at a step distal to stimulus recognition. |
