TCF7 and infection: scRNA-seq of transferred day-4.5 P14 cells re-isolated at day 15 after infection revealed six distinct clusters (Fig. 6b), spanning the spectrum from cells exhibiting features of progenitors (Tcf7, Il7r and Slamf6; clusters 1, 2, 3 and 5) to effector cells that lack progenitor markers and express higher levels of effector function (Ifng, Gzmb, Klrg1 and Cx3cr1; clusters 4 and 6) (Extended Data Fig. 5a).