Redirecting mouse T hybridoma against human breast and ovarian carcinomas: in vivo activity against HER-2/neu expressing cancer cells

Chimeric receptors comprising of the T-cell receptor-ζ cytoplasmic signalling chain fused to an extracellular ligand-binding domain of a single-chain antibody (scFv) have served as effective tools for redirecting cytotoxic T lymphocytes (CTL) against tumour cells. In this report, we constructed a chimeric scFv/ζ gene composed of the variable regions of an HER-2/neu-specific monoclonal antibody (MAb) joined to the TCR-ζ chain. The scFv(anti-HER-2/neu)/ζ chimeric gene was successfully expressed as a functional surface receptor in the MD.45 CTL hybridoma (MD.45-HER/ζ). More importantly, the scFv(anti-HER-2/neu)/ζ receptor was functionally active, since it triggered cytokine secretion by the MD.45-HER/ζ cells upon recognition of HER-2/neu-positive (+) tumour cell lines, or primary tumour cells from patients with HER-2/neu(+) cancers. The MD.45-HER/ζ-transduced cells also lysed HER-2/neu(+) target cells in vitro with high specificity. We tested the antitumour efficacy of scFv(anti-HER-2/neu)/ζ expressing MD.45 cells in severe combined immunodeficiency disease mice/human and murine tumour models. The adoptively transferred MD.45-HER/ζ cells both slowed significantly the growth of human FM3 melanoma or murine ALC leukaemic cells both transfected to express HER-2/neu. Our data demonstrate the feasibility of redirecting MD.45 CTL with the scFv(anti-HER-2/neu)/ζ chimeric receptor to respond specifically against HER-2/neu expressing tumour cells in vitro and in vivo. Moreover, they make it likely that T cells transduced with the same chimeric gene might be utilised in the treatment of patients with HER-2/neu(+) tumours.