Author(s): Yun CO, Nolan KF, Beecham EJ, Reisfeld RA, Junghans RP
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Abstract Immunoglobulin T-cell receptors (IgTCRs) combine the specificity of antibodies with the potency of cellular killing by grafting antibody recognition domains onto TCR signaling chains. IgTCR-modified T cells are thus redirected to kill tumor cells based on their expression of intact antigen on cell surfaces, bypassing the normal mechanism of activation through TCR-peptide-major histocompatibility complex (MHC) recognition. Melanoma is one of the most immunoresponsive of human cancers and has served as a prototype for the development of a number of immunotherapies. The target antigen for this study is the ganglioside GD3, which is highly expressed on metastatic melanoma with only minor immunologic cross-reaction with normal tissues. To determine an optimal configuration for therapy, four combinations of IgTCRs were prepared and studied: sFv-epsilon, sFv-zeta, Fab-epsilon, Fab-zeta. These were expressed on the surface of human T cells by retroviral transduction. IgTCR successfully redirected T-cell effectors in an MHC-unrestricted manner, in this case against a non-T-dependent antigen, with specific binding, activation, and cytotoxicity against GD3+ melanoma cells. Soluble GD3 in concentrations up to 100 microg/ml did not interfere with recognition and binding of membrane-bound antigen. Based on the outcomes of these structural and functional tests, the sFv-zeta construct was selected for clinical development. These results demonstrate key features that emphasize the potential of anti-GD3 IgTCR-modified autologous T cells for melanoma therapies.
This article was published in Neoplasia
and referenced in Journal of Carcinogenesis & Mutagenesis