Phage-selected primate antibodies fused to superantigens for immunotherapy of malignant melanoma

• Published in: Cancer Immunology, Immunotherapy Vol. 48; no. 12; pp. 691 - 702
• Main Authors: TORDSSON, J. M, OHLSSON, L. G, ABRAHMSEN, L. B, KARLSTRÖM, P. J, LANDO, P. A, BRODIN, T. N
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.03.2000; Springer-Verlag
• Subjects: Animals; Antibodies, Monoclonal - therapeutic use; Antigens, Neoplasm - immunology; Antineoplastic agents; Biological and medical sciences; Cross Reactions; Enterotoxins - therapeutic use; Epitopes - immunology; Female; Gene Library; Humans; Immunoglobulin Fragments - immunology; Immunoglobulin Fragments - therapeutic use; Immunotherapy; Immunotoxins - therapeutic use; Macaca fascicularis - immunology; Medical sciences; Melanoma - immunology; Melanoma - therapy; Mice; Mice, SCID; Muscle, Smooth - immunology; Neoplasm Transplantation; Original; Pharmacology. Drug treatments; Recombinant Fusion Proteins - immunology; Recombinant Fusion Proteins - therapeutic use; Species Specificity; Specific Pathogen-Free Organisms; Superantigens - therapeutic use; T-Lymphocytes, Cytotoxic - immunology; Human; Tumor associated antigen; Rodentia; Macaca fascicularis; Cytotoxicity; Malignant tumor; Monoclonal antibody; Fab-Fragment; In vitro; In vivo; Vertebrata; Phage display; Mammalia; Treatment; Mouse; Animal; Immunotherapy; T-Lymphocyte; Malignant melanoma; Primates; Simioidea; Superantigen; Fusion protein; Tumor cell
• ISSN: 0340-7004; 1432-0851
• DOI: 10.1007/s002620050018

The high-molecular-weight melanoma-associated antigen, HMW-MAA, has been demonstrated to be of potential interest for diagnosis and treatment of malignant melanoma. Murine monoclonal antibodies (mAb) generated in response to different epitopes of this cell-surface molecule efficiently localise to metastatic lesions in patients with disseminated disease. In this work, phage-display-driven selection for melanoma-reactive antibodies generated HMW-MAA specificities capable of targeting bacterial superantigens (SAg) and cytotoxic T cells to melanoma cells. Cynomolgus monkeys were immunised with a crude suspension of metastatic melanoma. A strong serological response towards HMW-MAA demonstrated its role as an immunodominant molecule in the primate. Several clones producing monoclonal scFv antibody fragments that react with HMW-MAA were identified using melanoma cells and tissue sections for phage selection of a recombinant antibody phage library generated from lymph node mRNA. One of these scFv fragments, K305, was transferred and expressed as a Fab-SAg fusion protein and evaluated as the tumour-targeting moiety for superantigen-based immunotherapy. It binds with high affinity to a unique human-specific epitope on the HMW-MAA, and demonstrates more restricted cross-reactivity with normal smooth-muscle cells than previously described murine mAb. The K305 Fab was fused to the superantigen staphylococcal enterotoxin A (D227A) [SEA(D227A)], which had been mutated to reduce its intrinsic MHC class II binding affinity, and the fusion protein was used to demonstrate redirection of T cell cytotoxicity to melanoma cells in vitro. In mice with severe combined immunodeficiency, carrying human melanoma tumours, engraftment of human lymphoid cells followed by treatment with the K305Fab-SEA(D227A) fusion protein, induced HMW-MAA-specific tumour growth reduction. The phage-selected K305 antibody demonstrated high-affinity binding and selectivity, supporting its use for tumour therapy in conjunction with T-cell-activating superantigens.