Optimization of T-cell Reactivity by Exploiting TCR Chain Centricity for the Purpose of Safe and Effective Antitumor TCR Gene Therapy

Abstract

Adoptive transfer of T cells redirected by a high-affinity antitumor T-cell receptor (TCR) is a promising treatment modality for cancer patients. Safety and efficacy depend on the selection of a TCR that induces minimal toxicity and elicits sufficient antitumor reactivity. Many, if not all, TCRs possess cross-reactivity to unrelated MHC molecules in addition to reactivity to target self-MHC/peptide complexes. Some TCRs display chain centricity, in which recognition of MHC/peptide complexes is dominated by one of the TCR hemi-chains. In this study, we comprehensively studied how TCR chain centricity affects reactivity to target self-MHC/peptide complexes and alloreactivity using the TCR, clone TAK1, which is specific for human leukocyte antigen-A Ã 24:02/Wilms tumor 1 235-243 (A24/WT1 235 ) and cross-reactive with B Ã 57:01 (B57). The TAK1b, but not the TAK1a, hemi-chain possessed chain centricity. When paired with multiple clonotypic TCRa counterchains encoding TRAV12-2, 20, 36, or 38-2, the de novo TAK1b-containing TCRs showed enhanced, weakened, or absent reactivity to A24/WT1 235 and/or to B57. T cells reconstituted with these TCRa genes along with TAK1b possessed a very broad range (>3 log orders) of functional and structural avidities. These results suggest that TCR chain centricity can be exploited to enhance desired antitumor TCR reactivity and eliminate unwanted TCR cross-reactivity. TCR reactivity to target MHC/ peptide complexes and cross-reactivity to unrelated MHC molecules are not inextricably linked and are separable at the TCR sequence level. However, it is still mandatory to carefully monitor for possible harmful toxicities caused by adoptive transfer of T cells redirected by thymically unselected TCRs.

CDR3β sequence motifs regulate autoreactivity of human invariant NKT cell receptors

“…Transduction rate of Vα24i TCRα gene ranges from 15-25% of total T cells. Expression of introduced TCR genes is maintained at least 3 weeks post transduction, as previously demonstrated in similar experiments using the same retrovirus vector and packaging cell line [26, 27]. …”

“…To create a de novo human iNKT TCR repertoire we transduced the invariant Vα24 (Vα24i) TCRα gene into human peripheral T cells. Similar methods were used previously to generate novel tumor-specific TCR repertoires with a wide range of affinity [26, 27]. The proportion of PBS-57-loaded CD1d tetramer-positive cells substantially increased, indicating the retrieval of a novel iNKT TCR repertoire using this approach (Fig.…”

“…Codon-optimized TCR cDNAs were produced by Thermo Fisher Scientific (Burlingame, CA). The cDNAs were cloned into pMX or pMX/IRES-EGFP vector to transduce all cell lines and primary human T cells [26]. Nucleotide sequencing was performed at the Centre for Applied Genomics, The Hospital for Sick Children (Toronto, Canada).…”

BET bromodomain inhibition enhances T cell persistence and function in adoptive immunotherapy models

“…All the dead mice underwent autopsy and the cause of death mOKT3 for 3 consecutive days. The full-length BATF cDNA was cloned into the pMX-internal ribosome entry site (IRES)-truncated nerve growth factor receptor (ΔNGFR) (32,54). HLA-A2/MART1 27-35 TCR (clone DMF5) genes were provided by Steven A. Rosenberg (NIH/NCI, Bethesda, MD) and subcloned into the pMX vector.…”

T cell receptor richness in peripheral blood increases after cetuximab therapy and correlates with therapeutic response

“…Indeed, there have been recent attempts to increase T cell specificity against shared TA and neoantigens. 4 …”