A human monoclonal antimelanoma single-chain Fv antibody derived from tumor-infiltrating lymphocytes

• Published in: Cancer research (Chicago, Ill.) Vol. 55; no. 16; pp. 3584 - 3591
• Main Authors: HUA ZHANG, LAKE, D. F, BARBUTO, J. A. M, BERNSTEIN, R. M, GRIMES, W. J, HERSH, E. M
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 15.08.1995
• Subjects: Amino Acid Sequence; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - immunology; Antibodies, Neoplasm - immunology; Antibody Specificity; Antineoplastic agents; Base Sequence; Biological and medical sciences; Clone Cells; Cloning, Molecular; DNA Primers - chemistry; Gene Rearrangement, B-Lymphocyte; Genes, Immunoglobulin; Humans; Immunoglobulin Fragments - immunology; Immunotherapy; Lymphocytes, Tumor-Infiltrating - immunology; Medical sciences; Melanoma - immunology; Molecular Sequence Data; Pharmacology. Drug treatments; Recombinant Proteins - immunology; Trypsin - pharmacology; Human; Tumor associated antigen; Methodology; Melanoma; Cytotoxicity; B-Lymphocyte; Tumor infiltrating lymphocyte; Malignant tumor; Monoclonal antibody; In vitro; Target; Specificity; Preparation; Established cell line; Recombinant protein; Technique; Tumor cell; Single chain antibody
• ISSN: 0008-5472; 1538-7445

With the development of recombinant DNA technology, it has become feasible to clone, construct, and express fully human immunoglobulin molecules. Here we report a novel methodology to make human antitumor single-chain Fv (scFv) antibodies from tumor-infiltrating B lymphocytes. We isolated and expanded tumor-infiltrating B lymphocytes from melanomas in the presence of Epstein-Barr virus. The transformed B cells secreting tumor-specific antibodies were identified and cloned by limiting dilution. From one B cell clone with specific melanoma reactivity, we captured the immunoglobulin variable region genes VH and Vk by PCR, sequenced the genes, and linked them together by PCR assembly with the use of a (Gly4Ser)3 linker. The scFv gene was then cloned into the pET21d vector and expressed. The obtained scFv protein with a M(r), of 29,000 was purified and biotinylated for further characterization. The scFv demonstrated specific tumor reactivity to 21 of 24 different melanoma cell lines and not to 14 nonmelanoma tumor cell lines, such as breast, ovarian, and colon cancer cells lines; normal human melanocytes as well as normal human leukocytes. These results were obtained in (a) a tumor cell ELISA, (b) fixed cell immunofluorescence, and (c) live cell flow cytometry. The immunoprecipitation results indicated that a protein antigen of M(r) 45,000 was recognized by the scFv. Since we reported previously that about 70% of human tumors of different histological types contain tumor-infiltrating B lymphocytes producing specific antitumor antibodies, this approach offers a rapid, effective method by combining in vitro B-cell expansion and PCR gene cloning to elucidate the repertoire of the human antitumor immune response and to make human monoclonal antitumor antibody molecules.