title: C6: A Monoclonal Antibody Specific for a Fibronectin Epitope Situated at the Interface between the Oncofoetal Extra-Domain B and the Repeat III8.
abstract: BACKGROUND
  Fibronectin (FN) is a large multidomain molecule that is involved in many cellular processes. Different FN isoforms arise from alternative splicing of the pre-mRNA including, most notably, the FN isoform that contains the "extra-domain-B" (ED-B). The FN isoform containing ED-B (known as B-FN) is undetectable in healthy adult tissues but is present in large amounts in neoplastic and foetal tissues as well as on the blood vessels during angiogenesis. Thus, antibodies specific for B-FN can be useful for detecting and targeting neoplastic tissues in vivo. We previously characterised C6, a new monoclonal antibody specific for human B-FN and we suggested that it reacts with the B-C loop of the type III repeat 8 which is masked in FN isoforms lacking ED-B and that the insertion of ED-B in FN molecules unmasked it. Here we have now consolidated and refined the characterization of this B-FN specific antibody demonstrating that the epitope recognized by C6 also includes loop E-F of ED-B.
  
  
  METHODS
  We built the three dimensional model of the variable regions of the mAb C6 and of the FN fragment EDB-III8 and performed protein:protein docking simulation using the web server ClusPro2.0. To confirm the data obtained by protein:protein docking we generated mutant fragments of the recombinant FN fragment EDB-III8 and tested their reactivity with C6.
  
  
  CONCLUSIONS
  The monoclonal antibody C6 reacts with an epitope formed by the B-C loop of domain III8 and the E-F loop of ED-B. Both loops are required for an immunological reaction, thus this monoclonal is strictly specific for B-FN but the part of the epitope on III8 confers the human specificity.
authors: Laboratory of Oncology, G. Gaslini Institute, Genova, Italy.
authors: Elisa
authors: E
authors: Ventura
authors: Sirius-biotech, c/o Advanced Biotechnology Center, Genova, Italy.
authors: Cinzia
authors: C
authors: Cordazzo
authors: Laboratory of Stem Cells, University of Genoa and Laboratory of Regenerative Medicine, IRCCS AOU San Martino-IST, Genova, Italy.
authors: Rodolfo
authors: R
authors: Quarto
authors: Sirius-biotech, c/o Advanced Biotechnology Center, Genova, Italy.
authors: Luciano
authors: L
authors: Zardi
authors: Laboratory of Biopolymers and Proteomics, IRCCS AOU San Martino-IST, Genova, Italy.
authors: Camillo
authors: C
authors: Rosano
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D003198:Computer Simulation; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D005353:Fibronectins / Q000737:chemistry*; D006801:Humans; D051379:Mice; D009154:Mutation; D009389:Neovascularization, Pathologic; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D012322:RNA Precursors; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D000939:Epitopes; D005353:Fibronectins; D020033:Protein Isoforms; D012322:RNA Precursors; D011994:Recombinant Proteins; C121542:oncofetal fibronectin