FUNCTIONAL-CHARACTERIZATION OF NK1.1(-6C(+) CELLS() LY)

It was found that NK1.1(+) cells were subdivided by their different ex pression pattern of Ly-6C antigen. To characterize their functional si gnificance in immunoregulation, we separated NK1.1(+)Ly6C(+) cells and NK1.1(+)Ly-6C(-) cells from C57BL/6 mouse nylon-passed spleen cells b y FACStar. Both NK1.1(+)Ly-6C(+) and NK1.1(+)Ly-6C(-) cells responded to the stimulation with IL-2 plus IL-12 and showed strong cytotoxicity against YAC-1 cells. However, these cells revealed different ability in terms of IFN-gamma production. Only NK1.1(+)Ly-6C(+) cells, but not NK1.1(+)Ly-6C(-) cells, cultured with IL-12 alone or IL-2 plus IL-12, produced high levels of IFN-gamma. Flow cytometric analysis demonstra ted that NK1.1(+)Ly-6C(+) cells consisted of NK1.1(+)CD3(-)Ly-6C(+) NK cells and NK1.1(+)CD3(+)Ly-6C(+) NKT cells. Therefore, we further sep arated these two populations from NK1.1(+)Ly-6C(+) cells to define the ir functions. Although, both NK1.1(+)CD3(-)Ly-6C(+) NK cells and NK1.1 (+)CD3(+) NKT cells showed the same level of cytotoxicity. It was clea rly demonstrated that NK1.1(+)CD3(+)Ly-6C(+) NKT cells were major immu noregulatory cells to produce IFN-gamma in respond to IL-12 alone or I L-2 plus IL-12. Copyright (C) 1996 Elsevier Science B.V.