title: Re-targeting of human lymphocytes expressing the T-cell receptor gamma/delta to ovarian carcinoma cells by the use of bispecific monoclonal antibodies.
abstract: TcR gamma/delta+ lymphocytes represent a small subset homogeneously composed of cytolytic T cells displaying unique motility and homing properties. Since the lytic machinery of these cells can be efficiently triggered by monoclonal antibodies (MAbs) directed to the TcR gamma/delta, such MAbs were used for the construction of bispecific MAbs in conjunction with an MAb specific for ovarian carcinoma cells. Hybrid hybridomas were obtained by fusing the Mov19 MAb (IgG2a)-producing hybridoma with either GI (IgG2a) or A13 (IgG1) hybridomas, secreting MAbs specific for 2 peripheral blood subsets of TcR gamma/delta+ lymphocytes. Hybrid hybridomas producing bispecific MAbs were screened according to their ability to induce ovarian carcinoma (IGROVI) target cell lysis by GI+ or A13+ T cell clones, respectively. The GI-derived GM33.9 bispecific MAb induced selective lysis of Mov19+ ovarian carcinoma target cells only by GI+ clones, whereas the A13-derived AM18.4 MAb was effective only in combination with A13+ clones. Neither the anti-TcR gamma/delta nor the Mov19 parental MAbs (used alone or in combination) induced target-cell lysis. The hybrid nature (IgG1/IgG2a) of the AM18.4 bispecific MAb was indicated by 2-color immunofluorescence experiments. Thus, both ovarian carcinoma and A13+ effector cells were double stained by AM18.4 bispecific MAb followed by PE-conjugated anti-IgG1 and FITC-conjugated anti-IgG2a second reagents. Polyclonal TcR gamma/delta+ cells were obtained by direct stimulation of peripheral blood mononuclear cells with Sepharose bead-conjugated anti-TcR gamma/delta MAbs and IL-2. The lines so obtained contained more than 90% of TcR gamma/delta+ cells after 4 weeks of culture, with an increase in TcR gamma/delta+ cell numbers ranging from 200 to 1,000-fold. These TcR gamma/delta+ cell lines efficiently lysed ovarian carcinoma target cells in the presence of bispecific MAb and may therefore represent a suitable source of effector cells for induction of ovarian carcinoma cell lysis.
authors.affiliation: Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Ferrini
authors.forename: I
authors.initials: I
authors.lastname: Prigione
authors.forename: S
authors.initials: S
authors.lastname: Mammoliti
authors.forename: M I
authors.initials: MI
authors.lastname: Colnaghi
authors.forename: S
authors.initials: S
authors.lastname: Ménard
authors.forename: A
authors.initials: A
authors.lastname: Moretta
authors.forename: L
authors.initials: L
authors.lastname: Moretta
mesh_terms: D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis* / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta