FIG. 4.

Loss of Gag-specific responses is associated with high baseline viral loads. Shown is the net change in Gag pool response breadth (x axis) (A) or the absolute changes in the magnitudes of Gag responses in subjects with a high (>10⁵ vRNA copies/ml; n = 14, gray diamonds) or a low (<10⁵ vRNA copies/ml; n = 18, black circles) baseline viral load (B); the median change is indicated. Gag-specific T-cell responses were detected after restimulation with Gag peptide pools with an IFN-γ ELISPOT assay and fresh PBMC as described in Materials and Methods. Responses that fell below the threshold of 70 SFC/10⁶ PBMC were counted as lost, and responses that newly emerged were counted as new. One subject was excluded because of a missing baseline viral load value. Statistical analysis was done with the Mann-Whitney test (A) or the Wilcoxon signed-rank test (B).