Regulation of Neutrophil Migration and Superoxide Production by Recombinant Tumor Necrosis Factors-α and -β: Comparison to Recombinant Interferon-γ and Interleukin-1 α

Abstract

AbstractWe compared the ability of recombinant human tumor necrosis factor-α (rHuTNF-α) and tumor necrosis factor-β (rHuTNF-β) to stimulate polymorphonuclear neutrophil (PMN) migration and superoxide production. Significant PMN migration occurred across polycarbonate filters after stimulation with rHuTNF-α at concentrations ranging from 10–7 to 10–10 mol/L and at 10–7 to 10–8 mol/L for rHuTNF-β and N-formylmethionyl-leucyl phenylalanine (FMLP), whereas recombinant human interferon-γ was only minimally active at 10–7 mol/L and recombinant human interleukin-1 α was inactive at the doses tested. In addition, antibodies to rHuTNF-α completely inhibited rHuTNF-α but not rHuTNF-β or FMLP-induced PMN migration. Combinations of rHuTNF-α and rHuTNF-β (at similar molar concentrations) stimulated PMN migration levels comparable to that obtained with rHuTNF-α alone. Checkerboard analyses performed by placing different concentrations of rHuTNF-α and rHuTNF-β above and below polycarbonate filters of microchemotaxis chambers demonstrated that rHuTNF-α and rHuTNF-β stimulated both chemotactic and chemokinetic responses by PMN. Additional studies demonstrated that 1 × 10–8 mol/L rHuTNF-α and 3 × 10–9 mol/L rHuTNF-β (which represents 104 U/mL of each cytokine) were similar in their ability to induce superoxide production by PMNs; however, at ten- to 100-fold lower molar concentrations (103 and 102 units), rHuTNF-α was significantly more active than rHuTNF-β. At the doses tested, both cytokines were less active than phorbol myristate acetate at stimulating O2- release. The results demonstrate that rHuTNF-α and rHuTNF-β differ quantitatively but not qualitatively in their effects on PMN functions in vitro and suggest that rHuTNF-β may be less toxic than rHuTNF-α in vivo.