TCR beta sequencing of blood and tumor samples from EG7.OVA bearing wildtype mice with OT-1 T cell transfer

We report the application of TCRβ sequencing to understand T cell repertoire of matched blood and tumor samples pre and post treatment in EG7.OVA tumor bearing mice with OT-1 cell transfer. TCRβ sequencing demonstrated that OT-1 (CASSRANYEQYF) was the most abundant T-cell clone in both blood and tumors of mRBC‑OVA-4-1BBL-IL-12 treated mice. To investigate the effects of mRBC‑OVA-4-1BBL-IL-12 on immune memory, the T cell repertoire was also analyzed before and after EG7.OVA and EL4 tumor rechallenge in cured and treatment-naive mice. TCRβ sequencing on T cells in peripheral blood showed that OT-1 clones increased in frequency after EG7.OVA challenge in previously cured mice. OT-1 frequency did not increase in treatment-naïve mice after tumor challenge, indicating that the tumor alone is insufficient to drive OT-1 cell expansion. We also evaluated the frequencies of unique TCRβ sequences in T cell clones that significantly expanded post EL4 challenge (EL4 responsive TCR). Increased frequency of EL4-responsive TCRs upon each tumor challenge (EG7.OVA and EL4) was associated with complete responders (mice that rejected EL4 challenge), suggesting that T-cell-mediated protection against parental tumor antigens was generated prior to EL4 challenge. Partial responders (delayed tumor growth compared with naïve mice) had increases in EL4-responsive TCR frequencies after EL4 challenge but not during the EG7.OVA rechallenge, whereas the non-responder (tumor growth similar to naïve mice) had minimal increases in TCR frequencies upon EL4 challenge. Overall, the ability to control EL4 tumors correlated with the expansion of EL4-responsive TCR clones. TCR repertoire analyses of matched blood and tumor samples, pre and post mRBC-OVA-4-1BBL-IL-12 treatment as well as pre and post EG7.OVA and EL4 challenge in cured mice in a murine lymphoma model with OT-1 T cell transfer ------------------------------------------------------- Submitter claims they are unable to provide raw fastq files: The authors state "Raw data were processed using the standard immunoSEQ Analyzer from Adaptive Biotechnologies Corporation (third party CRO), and this third party does not release raw data."