title: In vivo targeting of an anti-tumor antibody coupled to antigenic MHC class I complexes induces specific growth inhibition and regression of established syngeneic tumor grafts.
abstract: The concept of antibody-mediated targeting of antigenic MHC/peptide complexes on tumor cells in order to sensitize them to T-lymphocyte cytotoxicity represents an attractive new immunotherapy strategy. In vitro experiments have shown that an antibody chemically conjugated or fused to monomeric MHC/peptide can be oligomerized on the surface of tumor cells, rendering them susceptible to efficient lysis by MHC-peptide restricted specific T-cell clones. However, this strategy has not yet been tested entirely in vivo in immunocompetent animals. To this aim, we took advantage of OT-1 mice which have a transgenic T-cell receptor specific for the ovalbumin (ova) immunodominant peptide (257-264) expressed in the context of the MHC class I H-2K(b). We prepared and characterized conjugates between the Fab' fragment from a high-affinity monoclonal antibody to carcinoembryonic antigen (CEA) and the H-2K(b) /ova peptide complex. First, we showed in OT-1 mice that the grafting and growth of a syngeneic colon carcinoma line transfected with CEA could be specifically inhibited by systemic injections of the conjugate. Next, using CEA transgenic C57BL/6 mice adoptively transferred with OT-1 spleen cells and immunized with ovalbumin, we demonstrated that systemic injections of the anti-CEA-H-2K(b) /ova conjugate could induce specific growth inhibition and regression of well-established, palpable subcutaneous grafts from the syngeneic CEA-transfected colon carcinoma line. These results, obtained in a well-characterized syngeneic carcinoma model, demonstrate that the antibody-MHC/peptide strategy can function in vivo. Further preclinical experimental studies, using an anti-viral T-cell response, will be performed before this new form of immunotherapy can be considered for clinical use.
authors.affiliation: Institute of Biochemistry, University of Lausanne, CH-1066 Epalinges, Switzerland.
authors.forename: Alena
authors.initials: A
authors.lastname: Donda
authors.forename: Valérie
authors.initials: V
authors.lastname: Cesson
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Mach
authors.forename: Giampietro
authors.initials: G
authors.lastname: Corradin
authors.forename: F James
authors.initials: FJ
authors.lastname: Primus
authors.forename: Bruno
authors.initials: B
authors.lastname: Robert
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D002272:Carcinoembryonic Antigen / Q000276:immunology; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects / Q000276:immunology; D005260:Female; D006183:H-2 Antigens / Q000276:immunology*; D006801:Humans; D018796:Immunoconjugates / Q000276:immunology* / Q000494:pharmacology; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D016219:Immunotherapy, Adoptive / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008822:Mice, Transgenic; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D010047:Ovalbumin / Q000276:immunology; D012074:Remission Induction; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology; D014185:Transplantation, Isogeneic
chemical_list: D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D006183:H-2 Antigens; D018796:Immunoconjugates; D007140:Immunoglobulin Fab Fragments; D010047:Ovalbumin