BISPECIFIC MONOCLONAL-ANTIBODY ANTI-CD3-X-ANTI-TENASCIN - AN IMMUNOTHERAPEUTIC AGENT FOR HUMAN GLIOMA

Besides surgery, the therapeutic possibilities for the treatment of hu man gliomas include adoptive cellular immunotherapy, radioimmunotherap y, immunotherapy mediated by chemoimmunoconjugates and, more recently, bispecific monoclonal antibodies (biMAbs). Anti-CD3 x anti-tenascin ( TN) is the first reagent of a number of biMAbs under investigation for prospective use in vivo to maximize the cell-mediated cytolytic poten tial of glioma patients. This biMAb originated from the fusion of 2 pa rental hybridomas, made resistant by retrovirus-mediated infection to the different metabolic drugs, geneticin and methotrexate, respectivel y. The resulting hybrid hybridomas were selected on the basis of the d ouble specificity for CD3 and TN, cloned several times and grown under continuous metabolic pressure. The different families of recombinant antibodies were then purified by high-pressure liquid chromatography o n hydroxylapatite columns. Immunohistochemical studies on tumor specim ens of different origin and histotype have shown that the selected biM Ab presented a distribution pattern similar to that of the parental an ti-TN MAb, maintaining the same staining homogeneity and intensity. Mo reover, the mitogenic activity of anti-CD3 x anti-TN biMAb on peripher al blood mononuclear cells was similar to that featured by the parenta l anti-CD3 MAb. Furthermore, the hybrid molecule induced TNF-alpha gen e expression in activated PBMC. Finally, the anti-CD3 x anti-TN featur ed the desired killer targeting ability, being able to induce a signif icantly increased cytotoxic activity against TN+ tumor cells. (C) 1995 Wiley-Liss, Inc.