FIG 4.

BST2 antagonism by group O Nefs does not lead to BST2-dependent activation of ILT7. (A) Schematic representation of the experimental ILT7 NFAT-GFP reporter coculture system. (B to D) ILT7⁺ NFAT-GFP reporter cells were cocultured with control transfected HEK293T (no BST2) or BST2-expressing HEK293T (BST2) cells that were mock transfected or cotransfected with GFP-expressing NL4.3 WT and dU proviruses expressing either NL4.3 Nef or O-Nefs, as indicated. The degrees of surface BST2 downmodulation and ILT7 activation were determined by flow cytometry. ILT7 activation was evaluated as the percentage of GFP⁺ reporter cells. (B) Percentage of ILT7 activation after coculture with the indicated HEK293T cells relative to BST2-expressing HEK293T cells (100%) (n = 3). (C) Relative BST2 surface expression levels in cells cotransfected with BST2 and the indicated HIV proviruses (n = 3). Percent mean fluorescence intensities were calculated relative to values for dU HIV-producing cells (100%). (D) Percentage of ILT7 activation after coculture with the indicated BST2-expressing HEK293T cells relative to WT NL4.3-producing HEK293T cells (100%) (n = 3). Repeated-measures ANOVA with Bonferroni's multiple-comparison test was used (***, P < 0.001; **, P < 0.01). Error bars represent standard deviations.