TCR affinity for thymoproteasome-dependent positively selecting peptides conditions antigen responsiveness in CD8 + T cells

In the thymus, low-affinity T cell antigen receptor (TCR) engagement facilitates positive selection of the T cell repertoire. Takahama and colleagues now show TCR responsiveness of mature CD8 + T cells is fine-tuned by their affinity for positively selecting peptides in the thymus.