Resident dendritic cell density in the lymph node paracortex is preDC-estined.

Dendritic cells (DCs) are relatively short lived, yet DC frequencies in lymph nodes are stable. In this issue of Immunity, Ugur et al. reveal that type 1 conventional DCs (cDC1s) are maintained in the deep paracortex of the lymph node from a supply of preDCs that proliferate in nearby medullary vessels. Transition from preDC to cDC1 is regulated by Flt3L sensing.