title: Unique subset of natural killer cells develops from progenitors in lymph node.
abstract: Natural killer (NK) cells have been thought to develop from committed progenitors in the bone marrow. However, a novel pathway of thymus-dependent NK-cell development that produces a unique subset of NK cells expressing CD127 has recently been reported. We now have identified 2 populations of NK progenitors, one in the thymus and the other in the lymph node (LN). Immature double-negative 2 (CD4(-)CD8(-)CD44(+)CD25(+)) thymocytes have potential to produce NK cells with rearranged T-cell receptor gamma genes (Tcrgamma(+)) in vitro. Tcrgamma(+) NK cells are rare in spleen but relatively abundant in the thymus and LN. Approximately 20% of LN NK cells are Tcrgamma(+), and they are found at similar levels in both CD127(+) and CD127(-) subsets. Moreover, a subpopulation of LN cells resembling immature thymocytes differentiates into Tcrgamma(+) NK cells in vitro and also repopulates the NK compartment in lymphopenic mice. Athymic mice lack the LN NK progenitors expressing CD127 as well as Tcrgamma(+) NK cells. These results suggest that Tcrgamma(+) NK cells may be generated from unique progenitors in the thymus as well as in the LN.
authors.affiliation: Terry Fox Laboratory, 675 West 10th Ave, Vancouver, British Columbia, Canada V5Z 1L3.
authors.forename: Linnea L
authors.initials: LL
authors.lastname: Veinotte
authors.forename: Timotheus Y F
authors.initials: TY
authors.lastname: Halim
authors.forename: Fumio
authors.initials: F
authors.lastname: Takei
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D007694:Killer Cells, Natural / Q000166:cytology*; D008198:Lymph Nodes / Q000166:cytology*; D008231:Lymphopenia / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology; D013234:Stem Cells / Q000166:cytology*; D013950:Thymus Gland / Q000166:cytology
chemical_list: D016692:Receptors, Antigen, T-Cell, gamma-delta