T regulatory cells control numbers of NK cells and CD8alpha+ immature dendritic cells in the lymph node paracortex.
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 CD8alpha+ phenotypically immature dendritic cells present in LN T cell zones. We propose that the dominant influence of Treg cells on NK cell precursors and CD8alpha+ 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.
Giroux
Martin
M
Institute of Research in Immunology and Cancer, University of Montreal, Montreal, Quebec, Canada.
Yurchenko
Ekaterina
E
St-Pierre
Jessica
J
Piccirillo
Ciriaco A
CA
Perreault
Claude
C
D000818:Animals; D016827:CD8 Antigens / Q000378:metabolism*; D002454:Cell Differentiation / Q000276:immunology; D019070:Cell Lineage; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology* / Q000276:immunology*; D007694:Killer Cells, Natural / Q000166:cytology* / Q000276:immunology*; D008198:Lymph Nodes / Q000166:cytology* / Q000276:immunology; D018655:Lymphocyte Count; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype; D013154:Spleen / Q000166:cytology / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D016827:CD8 Antigens; C409469:CD8 antigen, alpha chain