Determination of a specific receptor for formyl-methionyl-leucyl-phenylalanine on th pulmonary alveolar macrophage and its relationship to chemotaxis and superoxide production.
3H-FMLP, a chemotactic peptide that resembles Escherichia coli chemotactic factor, is chemotactic for PAM, binds specifically to a site on the cell, and induces the generation of superoxide radicals by the cell. Scatchard analysis revealed an equilibrium dissociation constant at 26 degrees C of 1.45 x 10(-8)M and the presence of 1.7 , 10(5) receptors per cell. Binding was not inhibited by a partially purified C5a preparation or by the neutrophil-derived CCF but was inhibited by various N-formylated peptides. The order of potency of each peptide to inhibit 3H-FMLP binding was identical to the order of potency of each peptide to induce generation of superoxide by the PAM. Only small amounts of beta-glucuronidase activity and no lysozyme were detected in the supernatant after incubation of the cells for 30 min with varying concentrations of FMLP.
D000818:Animals; D001665:Binding Sites; D002633:Chemotaxis; D004305:Dose-Response Relationship, Drug; D005966:Glucuronidase / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D008264:Macrophages / Q000276:immunology*; D008715:Methionine / Q000031:analogs & derivatives*; D009239:N-Formylmethionine / Q000031:analogs & derivatives* / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009842:Oligopeptides / Q000378:metabolism*; D010100:Oxygen / Q000096:biosynthesis*; D011650:Pulmonary Alveoli; D011956:Receptors, Cell Surface / Q000032:analysis*; D044042:Receptors, Formyl Peptide; D013481:Superoxides / Q000096:biosynthesis*
D009842:Oligopeptides; D011956:Receptors, Cell Surface; D044042:Receptors, Formyl Peptide; D013481:Superoxides; D009239:N-Formylmethionine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D008715:Methionine; D005966:Glucuronidase; D010100:Oxygen