title: High-molecular-weight melanoma-associated antigen mimotope immunizations induce antibodies recognizing melanoma cells.
abstract: Size and posttranslational modifications are obstacles in the recombinant expression of high-molecular-weight melanoma-associated antigen (HMW-MAA). Creating a tumor antigen mimic via the phage display technology may be a means to overcome this problem for vaccine design. In this study, we aimed to generate an immunogenic epitope mimic of HMW-MAA. Therefore we screened a linear 9mer phage display peptide library, using the anti-HMW-MAA monoclonal antibody (mAb) 225.28S. This antibody mediates antibody-dependent cellular cytotoxicity (ADCC) and has already been used for anti-idiotype therapy trials. Fifteen peptides were selected by mAb 225.28S in the biopanning procedure. They share a consensus sequence, but show only partial homology to the amino acid sequence of the HMW-MAA core protein, indicating mimicry with a conformational epitope. One mimotope was chosen to be fused to albumin binding protein (ABP) as an immunogenic carrier. Immunoassays with 225.28S indicated that the mimotope fusion protein was folded correctly. Subsequently, the fusion protein was tested for immunogenicity in BALB/c mice. The induced anti-mimotope antibodies recognized HMW-MAA of 518A2 human melanoma cells, whereas sera of mice immunized with the carrier ABP alone showed no reactivity. These anti-mimotope antibodies were capable of inducing specific lysis of 518A2 melanoma cells in ADCC assays with murine effector cells. In conclusion, the presented data indicate that mimotopes fused to an immunogenic carrier are suitable tools to elicit epitope-specific anti-melanoma immune responses.
authors.affiliation: Department of Pathophysiology, Center of Physiology & Pathophysiology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Angelika B
authors.initials: AB
authors.lastname: Riemer
authors.forename: Brigitte
authors.initials: B
authors.lastname: Hantusch
authors.forename: Barbara
authors.initials: B
authors.lastname: Sponer
authors.forename: Georg
authors.initials: G
authors.lastname: Kraml
authors.forename: Christine
authors.initials: C
authors.lastname: Hafner
authors.forename: Christoph C
authors.initials: CC
authors.lastname: Zielinski
authors.forename: Otto
authors.initials: O
authors.lastname: Scheiner
authors.forename: Hubert
authors.initials: H
authors.lastname: Pehamberger
authors.forename: Erika
authors.initials: E
authors.lastname: Jensen-Jarolim
mesh_terms: D000418:Albumins / Q000378:metabolism; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000912:Antibodies, Neoplasm / Q000276:immunology*; D000920:Antibody-Dependent Cell Cytotoxicity; D000951:Antigens, Neoplasm / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006801:Humans; D007114:Immunization; D007167:Immunotherapy; D008545:Melanoma / Q000276:immunology* / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D018716:Molecular Mimicry; D010446:Peptide Fragments / Q000276:immunology*; D019151:Peptide Library; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012878:Skin Neoplasms / Q000276:immunology / Q000628:therapy; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014407:Tumor Cells, Cultured; D000099216:Chondroitin Sulfate Proteoglycan 4
chemical_list: D000418:Albumins; D000888:Antibodies, Anti-Idiotypic; D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D000939:Epitopes; D010446:Peptide Fragments; D019151:Peptide Library; D011993:Recombinant Fusion Proteins; D000099216:Chondroitin Sulfate Proteoglycan 4