Fig 1.
SIV infection and immunotherapies at ART initiation in infant macaques.
(A), Experimental design. Twenty-one infant rhesus macaques were orally challenged with SIVmac251 at 4 weeks of life. ART was started 1–2 weeks post infection. RMs were then divided into three groups: ART only controls (n = 7); ART + SIV RhmAbs (n = 7) and ART + SIV RhmAbs + N-803 (n = 7; *2 animals were prematurely euthanized due to adverse events resulting in a final n = 5). Animals received a single dose of SIV RhmAbs at 20 mg/kg s.c. each and a single dose of N-803 at 0.1 mg/kg. Both SIV RhmAbs and N-803 were administered on the same day as ART was initiated. ATI, Analytical Treatment Interruption. Created with Biorender.com. (B), Plasma concentrations of each SIV RhmAbs in μg/ml in the ART + SIV RhmAbs and ART + SIV RhmAbs + N-803 days post treatment. (C), Half-life of SIV RhmAbs in ART + SIV RhmAbs and ART + SIV RhmAbs + N-803 treated group. Individual data points are plotted with horizontal line drawn at the median.
Table 1.
Pharmacokinetic parameters of SIV Env RhmAbs.
Fig 2.
Plasma SIV viral loads before ART were similar across groups.
(A), SIV RNA copies in plasma were tracked longitudinally following infection with SIVmac251 and treatment with ART. Grey shading indicates the period of ART administration. (B), Peak viral loads were compared across groups by one-way ANOVA. Individual data points are plotted with horizontal line drawn at the median. (C), Time to viral suppression, defined as three consecutive undetectable timepoints, was compared across groups by one-way ANOVA. Individual data points are plotted with mean and SD shown. ns = not significant; p > 0.05.
Fig 3.
Faster SIV viral load decay in the ART + SIV RhmAbs group and opposite effect with the addition of N-803.
(A), Viral load values and individual fit trajectories for each animal after ART initiation are shown, with dashed lines indicating the lower limit of detection. (B), Simulated viral load decay trajectories by treatment group. Group mean trajectories show differences in the first and second phase decay rates. The trajectories for the ART only control and the ART + SIV RhmAbs treatment groups overlap after the first phase decay since there were no inferred effects of the SIV RhmAbs on the second phase decay rate. Dashed lines were used to indicate the overlap between the ART only group and the ART + SIV RhmAbs group.
Table 2.
Estimated model parameters for viral decay on ART.
Values represent mean and 95% confidence intervals of estimated parameters from a mixed effects biexponential decay model. Relative to the baseline ART only group (first column), treatment effects for both SIV RhmAbs and N-803 were estimated (second and third column), which contribute to the overall parameters for the ART + SIV RhmAbs and ART + SIV RhmAbs + N-803 groups (fourth and fifth columns). For treatment effects, blank cells indicate that no significant effect of the treatment on that parameter was identified. Half-lives were calculated from decay rates as T1/2 = ln(2)/b.
Fig 4.
Increased frequency of NK and T cells expressing Ki67 in the ART + SIV RhmAbs + N-803 group.
Frequency of NK cells (A), CD8+ T cells (B), and CD4+ T cells (C) expressing intracellular Ki67 measured by whole blood flow cytometry. Frequencies were compared at baseline (day 0) and day 4 after receipt of ART + SIVRhmAbs + N-803. Individual data points are plotted with mean and SD shown. Statistical analysis was performed using a paired Student’s t-test. (D-F) Frequency of peripheral blood NK cells (D), CD8+ T cells (E), and CD4+ T cells (F) expressing intracellular Ki67 were compared across groups in the first week after ART +/- SIV RhmAbs +/- N-803 administration. Individual data points are plotted with mean and SD shown. Statistical analysis was performed using the non-parametric Kruskal-Wallis test with multiple comparisons to assess for differences across groups. ns = not significant; p > 0.05.
Fig 5.
SIV reservoir decay did not differ across groups.
SIVgag DNA was quantified in sorted CD4+ T cells from peripheral blood (A), lymph nodes (B) and rectal biopsies (C) starting from week 0 (start of ART) to week 48 of ART. The fold change from week 0 to week 48 was calculated for SIVgag DNA in CD4+ T cells from peripheral blood (D) and lymph nodes (E). Intact proviral SIV DNA was quantified in sorted CD4+ T cells from peripheral blood (F), lymph nodes (G), and rectal biopsies (H) at week 48 of ART. Individual data points are plotted with horizontal lines drawn at the median. Statistical analysis was performed using the nonparametric Kruskal-Wallis test. Missing data points on graphs are the result of insufficient cells for the respective timepoint or missing paired data in the case of E, ART only group. ns = not significant; p > 0.05.
Fig 6.
Time to viral rebound and rebound AUC after ART interruption did not differ across groups.
(A-C), SIV RNA copies in plasma were tracked longitudinally following interruption of ART until euthanasia. (D), Time to viral rebound, defined as the first week SIV RNA was >60 copies/ml plasma, was compared across groups. Individual data points are plotted with horizontal line drawn at the mean with SD. Statistical analysis was performed using the nonparametric Kruskal-Wallis test. (E), Total area under the curve of rebound plasma viral loads in log for each group was compared. Individual data points are plotted with mean and SD shown. Statistical analysis was performed using the nonparametric Kruskal-Wallis test.