title: Characterization of a monoclonal antibody specific for novel Bcr/Abl out-of-frame fusion proteins.
abstract: The new tumor-specific antigens Bcr/Abl-OOF, identified in Philadelphia chromosome (Ph)-positive leukemia cells, are derived from an alternative splicing event involving BCR exons 1, 13, or 14 and ABL exons 4 and 5. The COOH-terminus of these transcription products contain an amino acid portion derived from an out-of-frame (OOF) reading of the ABL gene; these variants are expressed in Ph-positive chronic myelogenous leukemia (CML) and acute lymphocytic leukemia patients. Previously, we confirmed the presence of out-of-frame peptide-specific T cells in the peripheral blood of CML patients with the ability to lyse primary autologous CML cells. We also demonstrated that the out-of-frame Abl portion was immunogenic in HLA-A2.1 transgenic mice. Here we describe the production and characterization of monoclonal antibody 1D8G8, a new tool for localization and functional studies of the tumor antigen Bcr/Abl-OOF. This antibody recognizes the out-of-frame protein portion of the native full-length Bcr/Abl-OOF protein expressed in cells transiently transfected, as demonstrated by immunoprecipitation and immunofluorescence, and binds to a specific epitope of this antigen presented in association with HLA-A2.1 molecules at the surface of these cells, as demonstrated by flow cytometry. Thus this MAb could be useful to better understand how this new protein presents in Ph-positive cells beside the canonical Bcr/Abl fusion proteins.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Milan, Milan, Italy. claudia.casnici@gmail.com
authors.forename: Claudia
authors.initials: C
authors.lastname: Casnici
authors.forename: Gisella
authors.initials: G
authors.lastname: Volpe
authors.forename: Katia
authors.initials: K
authors.lastname: Crotta
authors.forename: Cristina
authors.initials: C
authors.lastname: Panuzzo
authors.forename: Donatella
authors.initials: D
authors.lastname: Lattuada
authors.forename: Carla Alba
authors.initials: CA
authors.lastname: Cabras
authors.forename: Renato
authors.initials: R
authors.lastname: Longhi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Saglio
authors.forename: Ornella
authors.initials: O
authors.lastname: Marelli
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis* / Q000276:immunology; D015153:Blotting, Western; D002460:Cell Line; D002498:Centrifugation; D002851:Chromatography, High Pressure Liquid; D003713:Dendritic Cells / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D016368:Frameshift Mutation / Q000235:genetics; D016044:Fusion Proteins, bcr-abl / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D016313:Genes, abl / Q000235:genetics; D006801:Humans; D006825:Hybridomas / Q000276:immunology / Q000378:metabolism; D047468:Immunoprecipitation; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D016044:Fusion Proteins, bcr-abl