Three weeks post‐infection, the mean CD8+/CD4+ T‐cell ratios in mice infected with EBV S457A/T465V (0.99) were significantly higher than in EBV wt (0.37)‐infected mice, while CD8+/CD4+ T‐cell ratios of EBV wt‐infected animals increased later, at 4 weeks post‐infection (Fig 6F). This evidence concerns the gene CD4 and infection.