Design of TCR Structural Variants That Retain or Invert the Normal Activation Signal

Abstract

We designed variant human TCRs composed of the full-length TCRa/b or extracellular and transmembrane domains of the associated CD3 subunits fused to polypeptides derived from proteins thought to either enhance or inhibit normal T cell function. First, we showed that the C termini of both the TCR a-and b-chains can accommodate specific additional sequences, without abrogating complex formation or acute sensitivity of the receptor. Replacement of ITAMs with ITIM-containing intracellular domains inverted the TCR signal (i.e., created a ligand-dependent inhibitory receptor). The normal signaling function of the CD3 complex was transferable to the TCR by eliminating all CD3 ITAMs and grafting three to six ITAMs onto the C termini of the a/b-chains, with no effect on acute sensitivity. The observation that TCR variants of such diverse C-terminal composition can fold and function as signaling receptors demonstrates substantial structural and functional malleability of TCRs. These results add to knowledge about TCR structure-function with regard to acute signaling and may provide a route to use TCRs in different ways for T cell therapy.

Robust In Vitro Pharmacology of Tmod, a Synthetic Dual-Signal Integrator for Cancer Cell Therapy

“…The Tmod system has remarkable properties. It is modular and can accommodate multiple target and receptor types ( 5 , 12 ). It is reversible and can cycle between ON and OFF states.…”