The viral load during the early stages of infection inversely correlated with the level of high-avidity SHIV-specific CD8⁺CTLs in the mucosal lymphoid tissues but not in blood. (A) Dynamics of the relationships between log viral load in blood on day 17 and avidity of the CL10-specific CTLs (against target cells pulsed with 10 μM, 1 μM, 0.1 μM, and 0.01 μM peptide) in MLNs before SHIV challenge. Individual data points for macaques in group 1 are color-coded as red squares; group 2, green diamonds; and group 3, blue circles. Spearman correlation coefficient and its P value were calculated. (B) Dynamics of correlation between high-avidity (0.001 μM), intermediate-avidity (1 μM), or low-avidity (10 μM) CL10-specific responses and log plasma viral load over time. The dynamics of high-avidity (0.001 μM) CTLs were significantly different from those of the CTLs measured at 1 and 10 μM peptide (P < .001). All correlation coefficients were negative (inverse correlation), but those with absolute value < 0.5 were not significant (above the horizontal line). (C) Correlation between high- and intermediate-avidity (0.1 μM and 1 μM) Gag372-specific responses before viral challenge and log of plasma viral load on day 17.