Figure 6.

  Model of mouse natural killer (NK) cell circulation at steady state. NK cells develop mostly in the bone marrow (BM) and, for the CD127⁺ fraction, also in lymph node (LN) and thymus. NK cells mature from the CD11b^dull stage to the double positive CD11b^highCD27^high (DP) and further to the CD27^dull stage in all organs, starting in the BM (vertical dotted arrows). Upon maturation, they acquire S1P₅ expression and exit the BM in a S1P₅‐dependent manner. In this model, the more NK cells express S1P₅, the more they exit the BM. Once in the periphery, they may return to BM and LN, through a CD62L‐dependent mechanism for the LN.