T regulatory cells control numbers of NK cells and CD8alpha+ immature dendritic cells in the lymph node paracortex
Giroux, M.; Yurchenko, E.; St-Pierre, J.; Piccirillo, C.A.; Perreault, C.
Journal of Immunology 179(7): 4492-4502
2007
ISSN/ISBN: 0022-1767 PMID: 17878345 Document Number: 612646
The spleen contains numerous NK cells whose differentiation profile is characterized by a preponderance of mature elements located mainly in the red pulp. In contrast, lymph nodes (LNs) contain few NK cells and they are sited mostly in T cell zones and skewed toward immature developmental stages. We show that, in mice, naturally occurring CD4(+)Foxp3(+) regulatory T (Treg) cells are both necessary and sufficient to repress accumulation of NK cells in resting LNs. Moreover, we present evidence that Treg cells hamper generation of mature NK cells through short-range interactions with NK precursors. In turn, mature NK cells specifically regulate the amount of CD8 alpha(+) phenotypically immature dendritic cells present in LN T cell zones. We propose that the dominant influence of Treg cells on NK cell precursors and CD8 alpha(+) immature dendritic cells explains why "quiescent" LNs in the absence of infection function as privileged sites for induction and maintenance of tolerance to peripheral Ags.