CD27 and neoplasm: In a model of continuous antigen exposure50 using human T cells that co-express a mesothelin-specific CAR (M5) and either ho2R or ho9R, signalling through ho9R resulted in superior tumour cell killing after repetitive tumour challenges, with an enrichment of CD45RA+CD27+ T cells with higher CCR7 expression, similar to ho9R–NYESO1 T cells (Fig. 4h and Extended Data Fig. 10g).