Shared and Distinct T-Cell Receptor Characteristics of CD4+ and CD8+ Drug-Specific T-Cells In Vitro Generated from Healthy Donors and Hypersensitive Patients.

The initiation of T-cell-mediated drug hypersensitivity reaction requires the formation of a human leukocyte antigen (HLA)-peptide-drug-T-cell receptor (TCR) complex. While specific interactions between HLA molecules and drug antigens are well-defined, the characteristics of drug binding to the TCR are unclear. Herein, we sequenced the TCR mRNAs of T-cells that express drug-specific HLAs (including HLA-A*31:01, HLA-B*15:02, and HLA-B*13:01) and exhibit drug-specific immune responses against carbamazepine, sulfamethoxazole, and dapsone. This study included a total of 46 in vitro-generated monoclonal drug-specific (CD4+ and CD8+) T-cell clones. The T-cell clones were characterized for their drug-specific immune response, including HLA restriction properties, interferon-γ secretion, and cross-reactive responses. RNA isolated from these cells was used for TCR library preparation and subsequent long-read sequencing analyses. T-cell characterization studies showed different drug-responsiveness properties among the clones. TCR sequencing revealed wide heterogeneity among drug-specific T-cells. Only TCR Vβ (TRBV) and TCR Jβ (TRBJ) segments of CD4+ T-cell clones displayed noticeable shared characteristics. A YEQYF residue on CDR3β, which correlates with the preferential use of TRBJ2-7, was identified in 5 out of 16 CD4+ carbamazepine-specific clones. However, CD8+ drug-specific clones showed no preferential usage of TCR α/β. Sequence alignment analyses among clones with similar or different drug-responsiveness properties also showed no evidence of structure-function correlation. In summary, TCR specificity against drug antigens appears to be nonrestrictive, suggesting that the extent of possible binding and its key determinants are not rigid.