title: Effect of a factor released by K562 malignant cells in culture on human neutrophil bactericidal activity.
abstract: We have previously demonstrated that k562 malignant cells in culture contain and release a low-molecular-mass (8-kDa) factor that inhibits adherence-related functions of neutrophils but does not alter fMet-Leu-Phe- or phorbol ester-induced oxidative burst (M. Amar, N. Amit, T. Pham Huu, S. Chollet-Martin, M.T. Labro, M.A. Gougerot-Pocidalo, and J. Hakim, J. Immunol. 144:4749-4756, 1990). In this study, we investigated the effects of this factor, referred to as inhibitory factor 1 (IF1), on the bactericidal activity of human polymorphonuclear cells (PMNs) on Staphylococcus aureus opsonized in various ways. S. aureus was used either nonopsonized or opsonized with heat-inactivated serum or normal serum containing complement factors. The bactericidal activity of PMNs preincubated with IF1-treated or control medium was examined by counting the surviving bacteria. The ability of IF1-treated PMNs to kill bacteria was diminished when they were opsonized with normal serum. When S. aureus was not opsonized or was opsonized with heat-inactivated serum, the bactericidal activity of IF1-treated PMNs was similar to that of controls. Likewise, the phagocytosis of IF1-treated PMNs was diminished when S. aureus was opsonized with normal serum but was not altered when S. aureus was not opsonized or was opsonized with heat-inactivated serum. These results suggest that the decrease in killing might be due to defective ingestion. The chemiluminescence response of IF1-treated PMNs was inhibited when S. aureus was not opsonized or was opsonized with normal serum. No effect on chemiluminescence was observed when S. aureus was opsonized with heat-inactivated serum. These results suggest that IF1 interferes not only with S. aureus stimulation of PMNs via complement receptors but also with oxygen-dependent bactericidal activity.
authors.affiliation: Unité 294, Institut National de la Santé et de la Recherche Médical, CHU Xavier Bichat, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Amar
authors.forename: N
authors.initials: N
authors.lastname: Amit
authors.forename: C
authors.initials: C
authors.lastname: Babin-Chevaye
authors.forename: T P
authors.initials: TP
authors.lastname: Huu
authors.forename: J
authors.initials: J
authors.lastname: Hakim
mesh_terms: D001685:Biological Factors / Q000494:pharmacology*; D002478:Cells, Cultured; D003165:Complement System Proteins; D006801:Humans; D008165:Luminol / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology*; D009895:Opsonin Proteins; D010587:Phagocytosis; D013211:Staphylococcus aureus / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D001685:Biological Factors; D009895:Opsonin Proteins; D008165:Luminol; D003165:Complement System Proteins