The activation of the neutrophil respiratory burst by anti-neutrophil cytoplasm autoantibody (ANCA) from patients with systemic vasculitis requires tyrosine kinases and protein kinase C activation.
The ability of antineutrophil cytoplasm autoantibodies (ANCA) from patients with systemic vasculitis to stimulate protein kinase C (PKC) and tyrosine kinases was examined in human neutrophils. Using the superoxide dismutase-inhibitable reduction of ferricytochrome C, the kinetics of ANCA-induced superoxide (O2-) production were characterized and subsequently manipulated by specific inhibitors of PKC and tyrosine kinases. With this approach, ANCA IgG, but not normal IgG or ANCA F(ab')2 fragments caused a time and dose dependent release of O2- from TNF-alpha primed neutrophils. The kinetics of ANCA-induced O2- production showed an initial 10-15 min lag phase compared to the N-formyl-L-methionyl-L-leucyl-L-phenylalanine response, suggesting differences in the signalling pathways recruited by these two stimuli. Inhibitor studies revealed that ANCA-activation involved members of both the Ca2+-dependent and -independent PKC isoforms and also tyrosine kinases. ANCA IgG resulted in the translocation of the betaII isoform of PKC at a time corresponding to the end of the lag phase of O2- production, suggesting that PKC activity may be instrumental in processes regulating the activity of the NADPH oxidase in response to ANCA. Tyrosine phosphorylation of numerous proteins also peaked 10-15 min after stimulation with ANCA but not normal IgG. These data suggest that PKC and tyrosine kinases regulate O2- production from neutrophils stimulated with autoantibodies from patients with systemic vasculitis.
Radford
D J
DJ
Divisions of Medical Science, The University of Birmingham, UK.
Lord
J M
JM
Savage
C O
CO
D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology / Q000494:pharmacology*; D003571:Cytochalasin B / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D016897:Respiratory Burst / Q000187:drug effects*; D015398:Signal Transduction / Q000276:immunology; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014657:Vasculitis / Q000201:enzymology* / Q000276:immunology
D019268:Antibodies, Antineutrophil Cytoplasmic; D004791:Enzyme Inhibitors; D007140:Immunoglobulin Fab Fragments; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D003571:Cytochalasin B; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate