USE OF A MURINE T-CELL HYBRIDOMA EXPRESSING HUMAN T-CELL RECEPTOR ALPHA-GENE AND BETA-GENE PRODUCTS AS A TOOL FOR THE PRODUCTION OF HUMAN T-CELL RECEPTOR-SPECIFIC MONOCLONAL-ANTIBODIES

We describe the production of mouse monoclonal antibodies specific for the human TcR using as the immunogen transfected murine T-cell hybridoma cells coexpressing mouse CD3 with human Jurkat TcR alpha and beta chains. The shortage of monoclonal antibodies (mAbs) specific for the human TcR-Valpha and Vbeta families reflects the difficulties in their production by conventional methods using whole human T cells or purified soluble receptors as immunogens. As an alternative strategy to circumvent these difficulties, we have generated a transfected mouse T-cell line expressing a human (jurkat) TcR alphabeta dimer in a complex with mouse CD3. The parental mouse T-cell line, TG40, is a cell surface TcR-negative, cytoplasmic CD3-positive variant of the mouse T-cell hybridoma 2B4. The human-TcR alphabeta expressing mouse transfectant was used to immunize mice with the same genetic background as the parent mouse T-cell line, and a human TcR-specific response was successfully achieved. MAb-producing hybridomas were generated by fusing spleen cells from the immunized mice with the mouse myeloma cell line NSO. Of 124 hybridoma supernatants screens, 72 showed reactivity to the human T-cell line Jurkat. Twenty-four of the hybridomas producing human (jurkat) TcR-specific antibodies were cloned and screened for reactivity to Jurkat TcR. Several IgG2b and IgM mAbs specific for the Jurkat T cell line were selected on the basis of their ability to modulate surface CD3 expression on Jurkat cells. Most of the antibodies do not stain other TcR-expressing human T cell leukemia cell lines, implying specificity for the variable domains of the Jurkat TcR. Each of the mAbs reacted with a minor population of peripheral blood lymphocytes (2%-6%), further indicating specificity for the variable domains of the TcR. Of the eight mAbs that were studied in detail, two appeared to have specificity for the Vbeta8 TcR family, as judged by their reactivity with T-cell lines, and the increase in Vbeta8+ T cells induced by culturing human peripheral blood mononuclear cells in the presence of the antibody. By using the system developed here, full-length human TcRalpha and TcRbeta cDNA clones made from polyclonally activated human peripheral blood T-lymphocytes will be transfected into the TcR-negative mouse T-cell line for the production of a panel of human TcR-specific monoclonal antibodies. These would be invaluable reagents for the study of the human TcR repertoire in health and disease.