Monoclonal Antibody Modulates Human Neutrophil Chemotaxis to N-formyl-Methionyl-Leucyl-Phenylalanine (fMLP)

Utilizing standard hybridoma techniques and a neutrophil chemotaxis assay for screening we produced a mouse monoclonal IgM antibody, 59/4, selected for specific inhibition of human neutrophil chemotaxis to the N-formyl-methionyleucyl- phenylalanine peptide (fMLP). Antibody 59/4 inhibited neutrophil chemotaxis to fMLP, but not human C5a or leukotriene B4. The antibody exhibited specific homogeneous binding to PMNs, heterogeneous binding to monocytes, and did not bind to lymphocytes in a pattern similar to the profile of N-formyl peptide binding in flow cytometric analysis. The antibody did not inhibit the binding of fluorescein-conjugated fMLPK or fML(3H)P ligands to neutrophils in flow cytometric or competitive binding assays. Other neutrophil functions including mycloperoxidase release and rosette formation with immunoglobulin or immunoglobulin C3b-coated sheep erythrocytes were not affected in the presence of antibody 59/4. These results suggest that 59/4 specifically inhibits chemotaxis to fMLP