Second-generation anti-carcinoembryonic antigen designer T cells resist activation-induced cell death, proliferate on tumor contact, secrete cytokines, and exhibit superior antitumor activity in vivo: a preclinical evaluation.

Abstract

This report describes the development and preclinical qualification tests of second-generation anti-carcinoembryonic (CEA) designer T cells for use in human trials. The progenitor first-generation immunoglobulin-T-cell receptor (IgTCR) that transmits Signal 1-only effectively mediated chimeric immune receptor (CIR)-directed cytotoxicity, but expressor T cells succumbed to activation-induced cell death (AICD). The second-generation CIR (termed "Tandem" for two signals) was designed to transmit TCR Signal 1 and CD28 Signal 2 to render T cells resistant to AICD and provide prolonged antitumor effect in vivo. A CIR was created that combines portions of CD28, TCRzeta, and a single chain antibody domain (sFv) specific for CEA into a single molecule (IgCD28TCR). As designed, the gene-modified Tandem T cells exhibit the new property of being resistant to AICD, showing instead an accelerated proliferation on tumor contact. Tandem T cells are more potent than first generation in targeting and lysing CEA+ tumor. Tandem T cells secrete high levels of interleukin-2 and IFNgamma on tumor contact that first-generation T cells lacked, but secretion was exhaustible, suggesting a need for interleukin-2 supplementation in therapy even for these second-generation agents. Finally, second-generation T cells were more effective in suppressing tumor in animal models. An advanced generation of anti-CEA designer T cells is described with features that promise a more potent and enduring antitumor immune response in vivo. These preclinical data qualify the human use of this agent that is currently undergoing trial in patients with CEA+ cancers.