Impact of the IL-15 superagonist N-803 on lymphatic reservoirs of HIV

Abstract

BACKGROUNDNK cell function is impaired in people with HIV (PWH), hindering their potential to reduce the lymphoid tissue (LT) reservoir. The IL-15 superagonist N-803 has been shown to enhance NK and T cell function and thus may reduce viral reservoirs.METHODSTo determine the impact of N-803 on LTs, we conducted a clinical trial where 10 PWH on effective antiretroviral therapy (ART) were given 3 subcutaneous 6 mcg/kg doses of N-803. We obtained PBMCs and lymph node (LN) and gut biopsies at baseline and after the last N-803 dose.RESULTSWe found a nonstatistically significant approximately 0.50 median log reduction in the frequency of viral RNA+ (vRNA+) and vDNA+ cells/g in the 6 participants with baseline and posttreatment LN biopsies. In the ileum, we observed reductions of vRNA+ cells in 8/10 participants and vDNA+ cells in all participants. We also found significant inverse correlations between NK cell proliferation and the frequency of vRNA+ cells and between NKG2A expression on NK cells and the frequency of vRNA+ cells.CONCLUSIONOur findings suggest N-803 may reduce the HIV reservoir in LTs of PWH on ART, an effect likely mediated by enhanced NK cell function. Controlled studies assessing the impact of NK cell therapy on HIV LTs are needed.TRIAL REGISTRATIONClinicalTrials.gov NCT04808908.FUNDINGNIH grants 5UM1AI126611, UL1TR002494, R01 AI147912, R35 CA283892, and UM1AI164561.

Keywords: AIDS/HIV; Immunotherapy; Infectious disease; NK cells.

Figure 1. Study schematic.

Flow diagram and design of the clinical trial.

Figure 2. Analysis of changes in frequency of vRNA⁺ and vDNA⁺ cells in LTs.

(A) Analysis of the frequency of vRNA⁺ cells in the 6 LNs obtained at baseline and the 10 LNs obtained at the post–N-803 time point using HIV RNA in situ hybridization by RNAscope. (B) Analysis of the frequency of vDNA⁺ cells by DNAscope. (C) Analysis of the frequency of vRNA⁺ cells in the ileum. (D) Analysis of the frequency of vDNA⁺ cells in the ileum. (E) Representative images from a participant’s LN showing vRNA⁺ and vDNA⁺ cells at the pre– and post–N-803 time points. Scale bar: 50 μm; inset, original magnification, 20×. Statistical analyses performed using an unpaired 2-tailed t test for A and B and paired 2-tailed t test for C and D; P values are shown above the pairings.

Figure 3. Measures and function of CD8⁺ T cells and NK cells in LNs.

(A) Frequency of CD8⁺ T cells in B cell follicles in the 6 individuals with both a pre– and post–time point. We counted CD8⁺ T cells inside of B cell follicles and in the parafollicular T cell zone to provide an estimate of the percentage of those cells in the B cell. (B) Grouped analysis of the log frequency of CD8⁺ T cells in the group with 6 baseline LN samples and the group with 10 post–N-803 LN samples. (C) Grouped analysis of the log frequency of NKG2A⁺ cells in 6 pre– and 10 post–N-803 LNs. (D) Representative images from a participant’s LN with an increase in both CD8⁺ and NKG2A⁺ cells at the pre– and post–N-803 time points. Scale bar: 100 μm. Statistical analyses performed using a paired 2-tailed t test in A and an unpaired 2-tailed t test in B and C; P values shown above pairings.

Figure 4. Correlations between vRNA⁺ frequency, cell types, and immune markers in LN samples.

(A) Correlation between the frequency of vRNA⁺ cells and the frequency of NK cells measured by ISH and IHC, respectively. (B) Correlation between the frequency of vRNA⁺ cells and the frequency of CD8⁺ T cells measured by ISH and IHC, respectively. (C) Correlation between the frequency of vRNA⁺ cells and Ki-67 expression measured by ISH and CyTOF, respectively. (D) Correlation between the frequency of vRNA⁺ cells and NKG2A expression measured by ISH and CyTOF, respectively. (E) Correlation between NKG2A expression and granzyme B expression measured by CyTOF. (F) Correlation between NKG2A expression and perforin expression measured by CyTOF. Analyses performed by linear regression; P values displayed on each panel. MMI, mean metal intensity.