Cord blood–derived V δ 2 + and V δ 2 − T cells acquire differential cell state compositions upon in vitro expansion

Human cord blood–derived γδ T cells (CB γδ ) display a highly diverse TCR γδ repertoire and have a unique subtype composition different from fetal or adult peripheral blood counterparts. We expanded CB γδ in vitro using an irradiated Epstein-Barr virus–transformed feeder cell–based modified rapid expansion protocol (REP). Single-cell RNA sequencing tracked progressive differentiation of naïve CB γδ into cells expressing neoantigen-reactive tumor-infiltrating lymphocyte as well as tissue-resident memory precursor–like and antigen-presenting cell–like gene signatures. TCR γδ clonal tracing revealed a bias toward cytotoxic effector differentiation in a much larger proportion of V δ 2 − clones compared to V δ 2 + clones, resulting in the former being more cytotoxic at the population level. These clonotype-specific differentiation dynamics were not restricted to REP and were recapitulated upon secondary nonviral antigen stimulations. Thus, our data showed intrinsic cellular differences between major subtypes of human γδ T cells already in operation at early postnatal stage and highlighted key areas of consideration in optimizing cell manufacturing processes.