FIGURE 5.

Enhanced activity of cyCD3ε⁺ NK cells in response to HCMV-infected cells in the presence of HCMV-specific Ab. PBMCs were collected from HCMV-seropositive donors. (A) PBMCs were cultured with K562 cells, neuroblastoma cell line BE(2)N cells in the presence of 3F8, or HCMV-infected fibroblasts with indicated sera. The surface CD107a expression on cyCD3ε⁺ NK cells from two donors is shown. (B) CD107a and IFN-γ responses in cyCD3ε⁺ and cyCD3ε^– NK cells against HCMV-infected cells in the presence of HCMV-specific Ab. Responses of cyCD3ε⁺ or cyCD3ε^– populations from the same individual are paired (n = 10). The indicated percentages of positive cells in FACS plots were determined as percentage of cyCD3ε⁺ NK cells and cyCD3ε^– NK cells. (C) IFN-γ responses of indicated NK cell subsets against HCMV-infected fibroblasts in the presence of HCMV-specific Ab. NK cell subsets were defined with the expression of cyCD3ε, NKG2C, and FcεRIγ among CD56^dim NK cells. (D and E) CD107a and IFN-γ responses among indicated NK cell populations following coculture with BE(2)N cells and the mAb 3F8 are shown. The indicated percentages of positive cells in FACS plots were determined as percentage of cyCD3ε⁺ NK cells and cyCD3ε^– NK cells. Dashed lines indicate populations from the same donor. *p < 0.05, **p < 0.01.