p24 Gag_209–218/HLA-Cw*0102 complexes on T2 cells lead to functional inhibition of primary KIR2DL2(+) NK cells.

<p>(<b>A</b>) Representative histograms of degranulation of KIR2DL2(−) (left panel) and KIR2DL2(+) (right panel) NK cells after co-incubation with peptide-pulsed T2 cells (tinted and black) or without target cells (clear). NK cell degranulation was measured flow cytometrically by surface expression of CD107a. (<b>B</b>) Different levels of NK cell degranulation between KIR2DL2(−) (dark grey) and KIR2DL2(+) (light grey) NK cells after co-incubation with peptide-pulsed T2 cells. Each column represents mean±SEM percentage of CD107a(+) NK cells of 5 of different individuals. Unspecific degranulation of NK cells measured without target cells was deducted from each column.</p

Ability of p24 Gag_209–218 peptide variants for HLA-Cw*0102 stabilization and KIR2DL2-Fc binding.

<p>(<b>A</b>) Differential expression of HLA-Cw*0102 on T2 cells after co-incubation with peptide variants of HIV-1 p24 Gag_209–218-L (AAEWDRLHPV). Peptide variants differed in length [9 or 10 amino acids (aa)] as well as in sequence (substitution of Leucine in position 7 with various amino acids). HLA-Cw*0102 expression is illustrated as relative median fluorescence intensity (RFI) as compared to unloaded T2 cells. Each column represents mean±SEM RFI of 4 independent experiments for each peptide variant. (<b>B</b>) Relative binding of KIR2DL2-Fc to T2 cells after co-incubation with selected HIV-1 p24 Gag_209–218variants. KIR2DL2-Fc binding is illustrated as RFI as compared to VAP-DA-pulsed T2 cells. Each column represents mean±SEM RFI of 3 independent experiments for each 10 aa variant. (<b>C</b>) Different levels of NK cell degranulation after co-incubation with T2 cells in the presence of different p24 Gag_209–218-L variants. Each column represents mean±SEM percentage of CD107a(+) NK cells of 4 different individuals. Unspecific degranulation of NK cells measured without target cells was deducted from each column. * indicates statistical significance as defined <i>p</i><0.05.</p

HIV-1 p24 peptide-dependent HLA-Cw*0102 stabilization on T2 cells.

<p>(<b>A</b>) Representative histograms of HLA-Cw*0102 stabilization on T2 cells as determined by flow cytometry. Histograms display HLA-Cw*0102 expression on T2 cells in the presence of control peptides VAP-FA and VAP-DA (black) at a concentration of 40 µg/ml as compared to unloaded T2 cells (grey tinted) and isotype control (clear). (<b>B</b>) HLA-Cw*0102 expression on HIV-1 p24 peptide-pulsed T2 cells. HLA-Cw*0102 expression is illustrated as relative median fluorescence intensity (RFI) as compared to unloaded T2 cells. Each column represents mean±SEM RFI of 5 independent experiments for each HIV-1 p24 OLP. A total of 59 HIV-1 p24 OLPs were analyzed, which previously showed strongest HLA-A/B/C stabilization as determined by an HLA-A/B/C antibody. Of those, 11 peptides with the highest HLA-Cw*0102 expression (>five-fold) were selected for subsequent KIR-Fc binding assays.</p