BTLA-HVEM engagement induces partial S-phase arrest. (A) Representative result showing the time course study of in vitro BrdU pulsing Vγ9Vδ2 T cells after 3 days (upper panel) and 4 days (lower panel) in culture with IL-2 + BrHPP (50 nM) ± HVEM 11.8 or IgG1. (B) Percentage of naïve Vγ9Vδ2 T cells in the S phase (upper panel) or in the G2/M phase (lower panel) after 3 days in culture with IL2+BrHPP±IgG1 or HVEM 11.8 (n = 12). Cells that may be in transition between 2 proliferation stages were excluded. Results were expressed as mean ± SEM, and statistical significance was established using the nonparametric paired Wilcoxon U test. *P < .05; **0.001 < P < .01; ***P < .001.