Generation of anti-NAG-2 mAb from patients' memory B cells: Implications for a novel therapeutic strategy in systemic sclerosis

Elisabetta Traggiai, Claudio Lunardi, Caterina Bason, Marzia Dolcino, Elisa Tinazzi, Roberto Corrocher, Antonio Puccetti

Research output: Contribution to journalArticlepeer-review

Abstract

We have previously reported that antibodies directed against the cytomegalovirus-derived protein UL94 cross react with the cell surface tetraspanin transmembrane 4 superfamily member 7 (TM4SF7 or NAG-2) molecule inducing apoptosis of endothelial cells and activation of fibroblasts in patients with systemic sclerosis (SSc). We aimed at generating a non-functional mAb directed against NAG-2 from patients' memory B cells. Direct and competitive ELISA methods have been used to evaluate the binding of antibodies from scleroderma patients' and controls' sera to the NAG-2 peptide. IgG memory B cells were sorted, EBV transformed and cloned to obtain NAG-2-specific mAbs. Endothelial cells and fibroblasts were cultured under standard conditions and used for functional assays. Anti-NAG-2-purified antibodies obtained from patients' Ig induce endothelial cell apoptosis and fibroblast proliferation. Patients' Igs depleted of the anti-NAG-2 fraction do not exert such functional activity. Therefore, the NAG-2 molecule represents a potential novel candidate for therapeutic intervention in SSc. Here, we describe the generation of a human mAb directed against the NAG-2 molecule. Such mAb does not retain any functional property and is able to block the effect of serum pathogenetic anti-NAG-2 antibodies. The majority of SSc patients present antibodies directed against tetraspanin NAG-2 and mediate both endothelial cell apoptosis and fibroblast proliferation, features of the disease. The anti-NAG-2 human mAb wehaveobtainedblocks signal transductionandthereforemaybe apotential candidate for anewtreatment in SSc, a disease where the current biological therapies have little or no efficacy.

Original languageEnglish
Pages (from-to)367-374
Number of pages8
JournalInternational Immunology
Volume22
Issue number5
DOIs
Publication statusPublished - Mar 5 2010

Keywords

  • Human mAb
  • Memory B cells
  • NAG-2
  • Systemic sclerosis

ASJC Scopus subject areas

  • Immunology

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