Cellular (a, c, e) and humoral (b, d) immune responses were assessed after challenge. IFN-γ ELISPOT assays (a) and ELISA and neutralizing antibody assays (b) were performed on days 0, 14, 28, 56 and 112 after challenge. NAb, neutralizing antibody; primary, primary isolate virus; TCLA, T-cell laboratory-adapted virus. Eight-colour ICS assays on day 28 (c), ADCVI assays at 1:100 serum dilution at the time points indicated (d), and Gag epitope mapping studies on day 28 (e) were also performed. Mean responses with standard errors are shown (a–e). f, Correlations between the breadth (left panels) or magnitude (right panels) of pre-challenge (top panels) or post-challenge (bottom panels) Gag-specific cellular immune responses and setpoint viral loads were evaluated by two-sided Spearman’s rank correlation tests. Monkeys immunized with rAd26/rAd5 (triangles), rAd35/rAd5 (diamonds), rAd5/rAd5 (squares) and sham (circles) vaccine regimens are depicted.