Identification of 11-2-1-1-1 T cell clone specific for WT1 peptides using high-throughput gene sequencing.

We previously identified a 21 T cell clone which was specific to CML patients, and demonstrated that 13/21 gene-modified CD3 T cells had specific cytotoxicity for HLA-A11 K562 cells. However, it remains unclear which antigen is specifically recognized by the 21 T cell clone. In this study, CD3 T cells from healthy donor peripheral blood were stimulated with the WT1 peptide or mixed BCR-ABL peptides in the presence or absence of IL-2 and IL-7. The distribution of the repertoire was analyzed after different stimulations. We found that the mixed BCR-ABL peptides induced clonally expanded 7-9-2-2-7 T cells while the Wilms Tumor 1 peptide induced clonally expanded 11-2-1-1-1 T cells by high-throughput sequencing and GeneScan. Interestingly, the sequence and CDR3 motif of 11-2 T cell clone are similar to the 21 (a different region naming system) T cell clone that we previously found in CML patients. Thus, our findings suggest that the 21 T cell clone found in CML patients might be a T cell clone that specifically recognizes WT1.