Characterization of the immature dendritic cells and cytotoxic cells both expanded after activation of invariant NKT cells with alpha-galactosylceramide in vivo.

Invariant natural killer T (iNKT) cells can perform multiple functions characteristic of both innate and acquired immunity. Activation of iNKT cells in vivo by repeated alpha-GalCer injections can induce immune tolerance, but the mechanisms responsible for such immunoregulation remain unclear. We prepared alpha-GalCer-liposomes, a single injection of which into mice resulted in the expansion of splenic CD11c(low)CD45RB(high) cells, which consists of two populations, CD180(+) and CD49b(+). Expansion of these cells was not observed in alpha-GalCer-liposome-treated mice deficient in IL-10 or iNKT cells. MHC and co-stimulatory molecules were down-regulated in CD11c(low)CD180(+) cells compared with conventional dendritic cells (cDCs), suggesting that the former possess characteristics of immature DCs. Meanwhile, the CD11c(low)CD49b(+) cells expressed IL-10 and Ctla4, and possessed greater lytic activity than resting NK cells. These observations suggest that both immature DCs (CD11c(low)CD180(+)) and cytotoxic cells (CD11c(low)CD49b(+)) might be expanded by alpha-GalCer-activated iNKT cells and could therefore be involved in immune tolerance.



Biochem Biophys Res Commun. 2008 Feb 16



Tamura Y, Teng A, Nozawa R, Takamoto-Matsui Y, Ishii Y.Laboratory for Vaccine Design, RIKEN Research Center for Allergy and Immunology (RCAI), 1-7-22, Suehiro, Tsurumi, Yokohama, 230-0045 Kanagawa, Japan.