Proinflammatory genes expression in granulocytes activated by native proteinase-binding fragments of anti-proteinase 3 IgG

The classical pathway of neutrophils activation due to cytoplasmic antineutrophil cytoplasmic antibodies (c-anca) involves specific antigen binding to proteinase-3 and activation of the immunoglobulin g receptors by the constant fragment of the antibody. a requirement for this double signaling was suggested also because proteinase-3 is presented within a complex of nb-1 glycoprotein lacking transmembrane domain. an integrin mac-1 receptor was postulated to cooperate in neutrophil stimulation by anti-proteinase 3 (anti-pr3). a characteristic profile of transcriptional activation of neutrophils by c-anca was described by us previously. we ascertained mrna expression of neutrophils following stimulation with antigen-binding fragments of native anti-pr3 igg. expression of targeted transcripts was compared with our previous results,in which intact anti-pr3 igg was used. human neutrophils were isolated from healthy volunteers negative for ancas. antigen-binding fragments of human anti-pr3 were prepared from sera of patients with granulomatosis with polyangiitis. we analyzed reactive oxygen species production and abundance of mrna of 151 genes by quantitative real time-pcr in neutrophils stimulated with anti-pr3 igg f(ab)2. we observed a consistent upregulation of 17 genes (cysltr1,hpgd,il1r1,il1rl1,mapk1,mapk8,nr3c1,pla2g7,ptgdr,cd302,dnajb1,f2r,f2rl1,ier3,rac1,rpl41,ptger3),whereas other 9 genes were up-regulated only in some donors. no reactive oxygen species production was observed in neutrophils stimulated with anti-pr3 f(ab)2. stimulation of neutrophils with f(ab)2 of anti-pr3 autoantibodies activated cells to a lesser extent than intact igg. however,several cellular pathways were up-regulated,involving calcium and phosphatidylinositol 3-kinase akt,nuclear factor-kb (nf- kb),mitogen-activated protein kinase (mapk) signaling. interestingly,binding of f(ab)2 to the pr-3 present on the surface of neutrophil is sufficient for lipid mediators and g-protein pathways activation. specific f(ab)2 antibodies against pr-3 seems not a good candidate for decoy therapy of granulomatosis with polyangiitis. © 2015 polish physiological society. all rights reserved.