Cellular architecture shapes the naïve T cell response.

After antigen stimulation, naïve T cells display reproducible population-level responses, which arise from individual T cells pursuing specific differentiation trajectories. However, cell-intrinsic predeterminants controlling these single-cell decisions remain enigmatic. We found that the subcellular architectures of naïve CD8 T cells, defined by the presence (T Ø ) or absence (T O ) of nuclear envelope invaginations, changed with maturation, activation, and differentiation. Upon T cell receptor (TCR) stimulation, naïve T Ø cells displayed increased expression of the early-response gene Nr4a1 , dependent upon heightened calcium entry. Subsequently, in vitro differentiation revealed that T Ø cells generated effector-like cells more so compared with T O cells, which proliferated less and preferentially adopted a memory-precursor phenotype. These data suggest that cellular architecture may be a predeterminant of naïve CD8 T cell fate.