Selective loss of surface NKG2D expression on NK cells from HCMV-exposed PBMCs. PBMCs from healthy donors were cultured for 3 days either alone (mock-treated) or in the presence of HCMV (TB40/E). Samples were analyzed by 3-color flow cytometry with a panel of mAbs specific for NKG2D (BAT221), NKp30 (AZ20), NKp46 (BAB281), and ILT-2 (HP-F1) in combination with anti-CD3 and -CD56 reagents. (A) Dot plots display the surface staining for each NK-cell receptor on gated CD56⁺CD3⁻ cells. (B) NKG2D expression on NK (CD56⁺CD3⁻) and CD3⁺ T cells from mock-treated cultures (gray profiles) or exposed to TB40/E (bold lines); thin lines correspond to the isotype control staining. Data correspond to samples from HCMV seronegative (d1, d2) and seropositive (d3, d4) donors, representative of 22 studied. (C) Surface expression of NKG2D was analyzed at days 1, 3, and 7 on CD56⁺CD3⁻ cells from HCMV- (bold lines) or mock-treated (gray profiles) PBMCs.