Role of HLA class I–specific inhibitory receptors in the regulation of NK-induced DC maturation and analysis of NK-cell–induced DC maturation in an autologous versus heterologous setting. (A) Immature DCs expressing either the HLA class I Cw7^+/+ or the HLA class I Cw4^+/+ phenotype were cocultured in the presence of allogeneic NK clones expressing different KIR phenotypes. After 2 days of coculture, DCs were analyzed for expression of CD83. The reported data of DC maturation were obtained in the presence of the following 4 representative NK clones: NK1 expressing the KIR2DL1⁺ KIR2DL2/3^– NKG2A^– phenotype, NK2 expressing the KIR2DL2/3⁺ KIR2DL1⁺ NKG2A^– phenotype, and NK3 and NK4 characterized by the KIR-negative NKG2A^dull and NKG2A^bright phenotype, respectively. Horizontal bars represent markers assigned on the basis of control cells (ie, cells incubated with the second reagent alone). The percentage of CD83⁺ cells is indicated. (B) A polyclonal NK-cell line was cocultured in the presence of either autologous or heterologous DCs. After 2 days of coculture, DCs were analyzed for expression of CD83 and CD86. Black bars and white bars indicate the percent of CD83⁺ DCs and CD86⁺ DCs, respectively. Similar results were obtained using NK-cell lines derived from 4 additional donors.