title: Development of a novel recombinant biotherapeutic with applications in targeted therapy of human arthritis.
abstract: OBJECTIVE
  To isolate recombinant antibodies with specificity for human arthritic synovium and to develop targeting reagents with joint-specific delivery capacity for therapeutic and/or diagnostic applications.
  
  
  METHODS
  In vivo single-chain Fv (scFv) antibody phage display screening using a human synovial xenograft model was used to isolate antibodies specific to the microvasculature of human arthritic synovium. Single-chain Fv antibody tissue-specific reactivity was assessed by immunostaining of synovial tissues from normal controls and from patients with rheumatoid arthritis and osteoarthritis, normal human tissue arrays, and tissues from other patients with inflammatory diseases displaying neovasculogenesis. In vivo scFv antibody tissue-specific targeting capacity was examined in the human synovial xenograft model using both (125)I-labeled and biotinylated antibody.
  
  
  RESULTS
  We isolated a novel recombinant human antibody, scFv A7, with specificity for the microvasculature of human arthritic synovium. We showed that in vivo, this antibody could efficiently target human synovial microvasculature in SCID mice transplanted with human arthritic synovial xenografts. Our results demonstrated that scFv A7 antibody had no reactivity with the microvasculature or with other cellular components found in a comprehensive range of normal human tissues including normal human synovium. Further, we showed that the reactivity of the scFv A7 antibody was not a common feature of neovasculogenesis associated with chronic inflammatory conditions.
  
  
  CONCLUSIONS
  Here we report for the first time the identification of an scFv antibody, A7, that specifically recognizes an epitope expressed in the microvasculature of human arthritic synovium and that has the potential to be developed as a joint-specific pharmaceutical.
authors.affiliation: Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Kamperidis
authors.forename: Tahereh
authors.initials: T
authors.lastname: Kamalati
authors.forename: Mathieu
authors.initials: M
authors.lastname: Ferrari
authors.forename: Margaret
authors.initials: M
authors.lastname: Jones
authors.forename: Toby
authors.initials: T
authors.lastname: Garrood
authors.forename: Malcolm D
authors.initials: MD
authors.lastname: Smith
authors.forename: Soraya
authors.initials: S
authors.lastname: Diez-Posada
authors.forename: Chris
authors.initials: C
authors.lastname: Hughes
authors.forename: Ciara
authors.initials: C
authors.lastname: Finucane
authors.forename: Stephen
authors.initials: S
authors.lastname: Mather
authors.forename: Ahuva
authors.initials: A
authors.lastname: Nissim
authors.forename: Andrew J T
authors.initials: AJ
authors.lastname: George
authors.forename: Costantino
authors.initials: C
authors.lastname: Pitzalis
mesh_terms: D000818:Animals; D000918:Antibody Specificity / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology; D004195:Disease Models, Animal; D000939:Epitopes / Q000276:immunology; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D055806:Microvessels; D010003:Osteoarthritis / Q000188:drug therapy* / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology / Q000627:therapeutic use; D057127:Single-Chain Antibodies / Q000276:immunology / Q000627:therapeutic use*; D013583:Synovial Membrane / Q000098:blood supply / Q000276:immunology; D014183:Transplantation, Heterologous
chemical_list: D000939:Epitopes; D011994:Recombinant Proteins; D057127:Single-Chain Antibodies