Fig. 2: Cytokine therapy reduces replication competent virus in lymphoid tissue, which is uniquely correlated with Env-specific NK cell activity.

The content of cell-associated SIV-RNA (log₁₀ copies per 10⁶ cells) was determined by qRT-PCR in snap frozen pellets of a PBMCs, b LN, and c RB prior to ART initiation (d35 p.i.), following two IL-21 cycles (d217 p.i.), and after one subsequent rIFNα cycle amid ongoing ART (d339 p.i. or d374 p.i.), as was cell-associated SIV-DNA (log₁₀ copies per 10⁶ cells) in d PBMCs, e LN, and f RB. a–f Data from individual RMs are overlaid against the mean ± SEM (in red): control (ART-only, black square; n = 5 RMs) and cytokine-treated (ART + IL-21 + IFNα, blue circle; n = 8 RMs). g From cryo-preserved, magnetically isolated LN CD4⁺ cells, the number of infectious units per million (IUPM) cells were measured with a limiting dilution quantitative viral outgrowth assay (QVOA; 3 serial dilutions plated in triplicate) in control (n = 4) and cytokine-treated RMs (n = 6). a–g Treatment phases are indicated with the following background shading: IL-21 (orange), rIFNα (red), and ART (gray). Data were analyzed with two-sided (95%), two-way ANOVA with Bonferroni’s correction with comparisons relative to controls and time. h The SIV reservoir contents in tissue (as indicated below) were correlated against phenotypes of activation (HLA-DR⁺CD38⁺) and proliferation (Ki-67⁺) in CD4⁺ and CD8⁺ T-cells; the frequency of HLA-E⁺ CD4⁺ T-cells and NKG2a/c⁺ CD8⁺ T-cells; and the Env-specific NK cell activity (as indicated at left) in all RMs (n = 13; days 35, 217, and 339/374 p.i. as matched data are available). Per each correlation the two-tailed (95% CI) Spearman’s rank correlation coefficient (rho) is represented as a double-gradient heatmap and the size of each data point corresponds inversely to the log₁₀-transformed Spearman’s p value. The false discovery rates (FDR) were calculated using SAS and significant values (Q < 0.05) are represented by a black border.