B2M and cancer: Jurkat cells CRISPR-engineered for deletion of endogenous TCR and β2M (to prevent aberrant TCR chain pairing and recognition of MR1 in trans on adjacent Jurkat cells) were transduced with the described TCRs and co-cultured with cancer cell lines expressing MR1*01, MR1*02, MR1*04, or C1R cells engineered to express supraphysiological MR1*01.