The regulation of HLA-E by miR-376a(e) during infection affects NK cell cytotoxicity.

<p>(a) FACS analysis of MICB levels on HFF cells transduced either with an anti-miR-376a sponge (black histogram), or an anti-miR-376a(e) sponge (grey histogram). Filled empty histogram represents background staining. Data are a representative of four independent experiments. (b) FACS analysis of HLA-E levels on HFF cells transduced either with a control sponge (empty grey histogram), an anti-miR-376a(e) sponge (black histogram, left), or an anti-miR-376a sponge (black histogram, right). Filled empty histogram represents background staining. Data are a representative of five independent experiments. (c) The percentage of NKG2A⁺ or NKG2C⁺ or CD94⁺ NK cells obtained from HCMV^neg (grey bars) and HCMV^pos (black bars) donors as detected by FACS. NK cells were identified by gating on CD56⁺CD3⁻ cells. (d and e) Killing of HCMV infected HFF cells transduced either with a control sponge or with a specific anti-miR-376a(e)-sponge (d) or with a control miRNA or miR-376a(e) (e). Killing was assessed 96 hrs post infection and was performed with bulk NK cells derived from four HCMV^neg and four HCMV^pos donors. The NK cells derived from the various donors were preincubated either with a CD94 blocking mAb (+block, dark grey bars), or with an isotype control (black bars) and then incubated with the ³⁵S methaionine-labeled target cells. Data shown are the relative killing by each specific donor, and the relative average killing by all HCMV^neg or HCMV^pos donors combined (x-axis). The killing of the control-sponge (Ctrl, d) or control-miRNA (Ctrl, e) expressing HFF cells was set as 1 (marked by a dashed line). Shown are relative average killing ± S.D. *<i>P</i><0.05, by Student's t-test. Of note, all single experiments also showed statistically significant effects (<i>P</i><0.05, by Students' t-test) based on relative mean±S.D. of quadruplets.