IL-15 promotes the preferential expansion of NKG2C⁺ cells in CD56⁺ populations stimulated with HCMV-infected cells. CD56⁺ populations sorted from PBLs of HCMV⁺ donors were cultured with mock- or HCMV (AD169)-infected MRC-5 cells, infected 24 hours before, in the presence of IL-2 (10 U/mL). (A) Proliferation of CFSE-labeled CD56⁺ cells cultured for 8 days with mock- or HCMV-infected cells supplemented with IL-15 at day 4. (B) Distribution of NKG2A⁺ and NKG2C⁺ subsets in CD56⁺ lymphocytes cocultured for 8 days with mock- or HCMV-infected cells in the presence of IL-15, added at days 1 or 4. The data are representative of 6 experiments performed.