A Retroviral Vector that Directs Simultaneous Expression of α and β T Cell Receptor Genes

Abstract

The transfer of α/β T cell receptor (TCR) genes into T lymphocytes or their precursors could provide a means to increase frequency of tumor- or pathogen-specific cytotoxic T lymphocytes. To begin to address this possibility, we have used class I MHC-restricted α/β TCR cDNAs to develop a retroviral TCR expression vector. α- and β-chain cDNAs were inserted into a derivative of the LN series of retroviral vectors, with the retroviral LTR directing expression of TCR-β and an internal cytomegalovirus promoter/enhancer driving TCR-α expression. The variable region fragments can be replaced using unique restriction sites that have been introduced into the proximal constant regions. We have used this vector system to transfer two different pairs of α/β TCR genes into an α- and β-chain-deficient T cell hybridoma. TCR¯ hybridoma cells were transduced by coculture with pools of virus-producing cells, and fluorescence-activated cell sorting was used to enrich for cells expressing the transduced TCR. Transduction with either α/β TCR restores stable, long-lived expression of the α/β TCR complex. TCR-mediated signal transduction is also reconstituted, as demonstrated by the ability of transduced cells to secrete IL-2 following stimulation with Vβ-specific antibodies. Our results suggest that α/β T cell receptor gene transfer could provide a basis for new approaches to immunotherapy, and that further studies examining the in vivo fate of transduced TCR are possible.