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. 2013 May 23;9(5):e1003383. doi: 10.1371/journal.ppat.1003383

Figure 9. HLA-mediated inhibition of NK cell recognition of HCMV infection.

Figure 9

Experiments were performed with polyclonal NK cells (A, C, E, G) or NK cell clone #29 (B, D, F, G) from donor AJU. (A, B) Analysis of KIR expression by flow cytometry. (C, D) Killing by NK cells of the MHC class I-deficient cell lines K562, Daudi and L721.221, HLA-C*0602 or C*0702-transfected L721.221 cells, uninfected MRC-5 fibroblasts, or MRC-5 infected with CMV-wt at moi = 5, at an effector∶target ratio of 2. Data are shown as mean+SD of four replicates from one representative experiment out of four. (E, F) NK cell-mediated killing of uninfected (n.i.) and HCMV-infected fibroblasts over time after infection. Fibroblasts were or were not pretreated with IFN-γ before infection as indicated. (G) Blockade of NK cell mediated-killing by monoclonal antibodies specific for HLA-ABC or KIR2DL2/3 (both IgG2a) or a matched isotype control. Targets were pretreated with IFN-γ. Blockade of the non-KIR ligand HLA-A2 served as additional negative control. The HLA class I type of MRC-5 fibroblasts is HLA-A*0201, A*2902, B*0702, B*4402, C*0501, C*0702. HLA-C*0702 is the only ligand of KIR2DL3 expressed by MRC-5 cells. Killing was assessed at an effector∶target ratio of 2. Data are shown as mean+SD of triplicate samples from one out of two independent experiments.