Theodor-Kocher-Institut, University of Bern, Switzerland.
Human blood mononuclear cells were cultured for 24 h in the presence of LPS (100 ng per 5 x 10(6) cells), and a monocyte-derived neutrophil-activating factor (NAF) was purified to apparent homogeneity from the conditioned media. The purification consisted of ammonium sulphate precipitation, gel filtration, chromatography on phosphocellulose followed by hydroxylapatite, and reversed-phase HPLC on C4 and CN-propyl columns. Amino acid sequence analysis (32 of 50 presumed residues) shows that NAF is a novel peptide with little homology to known ones. Crude and pure NAF stimulated human neutrophils to release granule enzymes and to produce superoxide and H2O2.