title: Human antibody derivatives against the fibroblast activation protein for tumor stroma targeting of carcinomas.
abstract: The fibroblast activation protein (FAP) is selectively expressed on activated fibroblasts of the tumor stroma on more than 90% of lung, breast and colon carcinomas. The high prevalence and abundance of FAP(+) stroma make it a promising target for in vivo diagnosis and therapy of a variety of carcinomas. We describe the humanization of the murine FAP-specific MAb, F19, which has already been clinically used for in vivo diagnostic purposes. Using phage display technology and human V-repertoires, VL and VH regions of F19 were replaced by analogous human V-regions while retaining the original HCDR3 sequence in order to maintain F19 epitope specificity. The resulting human single-chain fragments of immunoglobulin variable regions (scFv 34, scFv 18) showed affinities of 6 nM on cell membrane-bound FAP. scFv 34 was expressed as a bivalent minibody (Mb 34). The antigen-binding characteristics of Mb 34 were comparable to the parental and a complementarity-determining region (CDR)-grafted version of F19. This was revealed by binding competition studies, FACS analyses and immunohistochemistry on various tumor samples including breast, colon and lung carcinomas. Importantly, compared with the CDR-grafted humanized scFv version of F19, the V-regions of the selected human scFv 34 showed sequence identity with the parental antibody (Ab) only over the short, 15-amino acid long HCDR3. Thus, a largely reduced xenoantigenic potential is expected. These human Ab derivatives are suitable to develop novel therapeutic concepts with broad applicability for a wide variety of histological carcinomas based on tumor stroma targeting.
authors: Institut für Zellbiologie und Immunologie, Universität Stuttgart, Allmandring 32, D-70569 Stuttgart, Germany.
authors: M
authors: M
authors: Mersmann
authors: A
authors: A
authors: Schmidt
authors: J F
authors: JF
authors: Rippmann
authors: T
authors: T
authors: Wüest
authors: B
authors: B
authors: Brocks
authors: W J
authors: WJ
authors: Rettig
authors: P
authors: P
authors: Garin-Chesa
authors: K
authors: K
authors: Pfizenmaier
authors: D
authors: D
authors: Moosmayer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018033:Antibodies, Bispecific / Q000235:genetics / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000276:immunology* / Q000378:metabolism; D014408:Biomarkers, Tumor; D002277:Carcinoma / Q000276:immunology* / Q000378:metabolism; D010450:Endopeptidases; D000939:Epitopes / Q000276:immunology; D016326:Extracellular Matrix Proteins / Q000276:immunology / Q000378:metabolism; D018093:Gelatinases; D006133:Growth Substances / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D019151:Peptide Library; D011993:Recombinant Fusion Proteins / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000276:immunology* / Q000378:metabolism; D013696:Temperature; D000099167:Fibroblast Activation Protein Alpha
chemical_list: D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D010450:Endopeptidases; D000939:Epitopes; D016326:Extracellular Matrix Proteins; D018093:Gelatinases; D006133:Growth Substances; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D008565:Membrane Proteins; D019151:Peptide Library; D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; D000099167:Fibroblast Activation Protein Alpha