a–e, SIV-specific responses in peripheral blood at 4 and >12 w.p.i. in IFN-1ant (Ant, n =6) and placebo (Plac, n =6) macaques by frequency of IFN-γ+(a), TNF+ (b), perforin+ (c), granzyme B+ (d) and CD107+ (e) CD8 T cells. T-cell exhaustion in peripheral blood and lymph nodes (LN) at >16 w.p.i. based on frequency of PD-1+ CD4 (f) and CD8 (h) T cells and ICOS+ (g) CD8 T cells. For all panels, P values at different time points within treatment groups were calculated by Wilcoxon matched pairs signed rank test and between groups by Mann–Whitney U test. IFN-1ant-treated macaques are represented in red, placebo-treated macaques in blue.