The cleavage site of C5 from man and animals as a common target for neutralizing human monoclonal antibodies: In vitro and in vivo studies

Roberto Marzari, Daniele Sblattero, Paolo Macor, Fabio Fischetti, Renato Gennaro, James D. Marks, Andrew Bradbury, Francesco Tedesco

Research output: Contribution to journalArticle


The isolation of an anti-C5 single-chain fragment variable (scFv) antibody, TS-A12/22, from a human phage display library, is described. This antibody inhibits the activation of C5 and the assembly of the terminal complement complex implicated in cell and tissue damage. Using antibody-sensitized sheep erythrocytes and rabbit red cells as target cells in hemolytic assays, we found that TS-A12/22 inhibited the activation of C5 by the convertases of both classical and alternative pathways. Western blot analysis and competition experiments with synthetic peptides showed that TS-A12/22 reacted with the α chain of C5 and recognized the cleavage site of this complement component by the C5 convertase. As a result, the antibody prevented splitting of C5 and inhibited the generation of C5a and of the terminal complement complex. The identification of the TS-A12/22 recognition site as a conserved sequence in man, mouse, rat and rabbit enabled the demonstration of in vitro inhibition of complement activity in these species. The scFv TS-A12/22 was tested in a rat model of antigen-induced arthritis and proved to be effective in preventing influx of polymorphonuclear cells into the knee joint and C9 deposition on synovial tissue.

Original languageEnglish
Pages (from-to)2773-2782
Number of pages10
JournalEuropean Journal of Immunology
Issue number10
Publication statusPublished - Oct 2002



  • Complement
  • Inflammation
  • Phage display library
  • Single-chain fragment variable antibody

ASJC Scopus subject areas

  • Immunology

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