Stabilization of soluble high-affinity T-cell receptor with de novo disulfide bonds

Soluble T-cell receptors (TCRs) have recently gained visibility as target-recognition units of anticancer immunotherapeutic agents. Here, we improved the thermal stability of the well-expressed high-affinity A6 TCR by introducing pairs of cysteines in the invariable parts of the alpha- and beta-chain. A mutant with a novel intradomain disulfide bond in each chain also tested superior to the wild-type in the accelerated stability assay. Binding of the mutant to the soluble cognate peptide (cp)-MHC and to the peptide-loaded T2 cell line was equal to the wild-type A6 TCR. The same stabilization motif worked efficiently in TCRs with different specificities, such as DMF5 and 1G4. Altogether, the biophysical properties of the soluble TCR molecule could be improved, without affecting its expression level and antigen-binding specificity.