Figure 7. Effect of CD8⁺ T cell depletion on SIV infection dynamics prior to ART withdrawal.

(A) Individual pvl profiles monitored by a high-sensitivity assay (limit of detection, 1 RNA copy/mL) prior to and during anti-CD8β or IgG isotype control mAb treatment, prior to ART cessation. The area in gray denotes pvl values below threshold of the standard assay (15 RNA copies/mL). There was no significant difference between treatment groups in instance and duration of above–standard threshold pvl as determined by Wilcoxon’s rank-sum and Fisher’s exact tests. (B) Comparison of cell-associated SIV RNA (left panel) and DNA (right panel) levels in PBMCs, LNs, and BM (copies per 1 × 10⁶ cell equivalents) after 9 weeks of treatment with anti-CD8β or IgG control mAb. Each data point represents a single determination from an individual RM. Plots show jittered points with a box from first to third quartiles (IQR) and a line as the median, with whiskers extending to the farthest data point within 1.5 × IQR above and below the box, respectively. (C) Quantification of the number of SIV RNA⁺ cells per 1 × 10⁵ cells (left panel) and the average number of SIV RNA copies per cell measured in LN tissue sections by RNAscope. In B and C, Wilcoxon’s rank-sum test was used to determine the significance of differences between treatment groups, first excluding RMs with incomplete CD8⁺ Tm depletion, and then including all treated RMs versus IgG controls (unadjusted P values shown). In all panels, RMs with effective CD8⁺ T cell depletion (n = 7) are shown in red, RMs with incomplete CD8⁺ T cell depletion (n = 3) are shown in green, and IgG isotype controls (n = 10) are shown in blue. Closed symbols indicate Mamu-A*01⁺ RMs and open symbols indicate Mamu-B*08⁺ RMs.