Brief Report: HIV Antibodies Decline During Antiretroviral Therapy but Remain Correlated With HIV DNA and HIV-Specific T-Cell Responses

Background: In people with HIV on antiretroviral therapy (ART), the relationship between HIV-specific immune responses and measures of HIV persistence is uncertain. Methods: We evaluated 101 individuals on suppressive ART in the AIDS Clinical Trials Group A5321 cohort. Cell-associated (CA) HIV DNA and RNA levels and HIV antibody concentrations and avidity to Env/p24 were measured longitudinally at years 1, 4, and 6-15 after ART initiation. Plasma HIV RNA by single copy assay and T-cell responses (IFN-γ ELISPOT) against multiple HIV antigens were measured at the last time point. Results: HIV antibody levels declined significantly with increasing time on ART (19%/year between year 1 and 4). HIV antibody levels correlated with T-cell responses to HIV Pol (r = 0.28, P = 0.014) and to Nef/Tat/Rev (r = 0.34; P = 0.002). HIV antibody and T-cell responses were positively associated with HIV DNA levels; for example, at the last time point (median 7 years on ART), r = 0.35 for antibody levels and HIV DNA (P < 0.001); r = 0.23 for Nef/Tat/Rev-specific T-cell responses and HIV DNA (P = 0.03). Neither antibody nor T-cell responses correlated with cell-associated HIV RNA or plasma RNA by single copy assay. Conclusions: In individuals on long-term ART, HIV-specific antibody and T-cell responses correlate with each other and with HIV DNA levels. The positive correlation between HIV immune responses and HIV DNA implies that the immune system is sensing, but not clearing, infected cells, perhaps because of immune dysfunction. Measuring immune responses to HIV antigens may provide insight into the impact of reservoir-reducing strategies

Levels of HIV-1 persistence on antiretroviral therapy are not associated with markers of inflammation or activation

Antiretroviral therapy (ART) reduces levels of HIV-1 and immune activation but both can persist despite clinically effective ART. The relationships among pre-ART and on-ART levels of HIV-1 and activation are incompletely understood, in part because prior studies have been small or cross-sectional. To address these limitations, we evaluated measures of HIV-1 persistence, inflammation, T cell activation and T cell cycling in a longitudinal cohort of 101 participants who initiated ART and had well-documented sustained suppression of plasma viremia for a median of 7 years. During the first 4 years following ART initiation, HIV-1 DNA declined by 15-fold (93%) whereas cell-associated HIV-1 RNA (CA-RNA) fell 525-fold (>99%). Thereafter, HIV-1 DNA levels continued to decline slowly (5% per year) with a half-life of 13 years. Participants who had higher HIV-1 DNA and CA-RNA before starting treatment had higher levels while on ART, despite suppression of plasma viremia for many years. Markers of inflammation and T cell activation were associated with plasma HIV-1 RNA levels before ART was initiated but there were no consistent associations between these markers and HIV-1 DNA or CA-RNA during long-term ART, suggesting that HIV-1 persistence is not driving or driven by inflammation or activation. Higher levels of inflammation, T cell activation and cycling before ART were associated with higher levels during ART, indicating that immunologic events that occurred well before ART initiation had long-lasting effects despite sustained virologic suppression. These findings should stimulate studies of viral and host factors that affect virologic, inflammatory and immunologic set points prior to ART initiation and should inform the design of strategies to reduce HIV-1 reservoirs and dampen immune activation that persists despite ART

Clinical trial of the anti-PD-L1 antibody BMS-936559 in HIV-1 infected participants on suppressive antiretroviral therapy

Background. Reversing immune exhaustion with an anti-PD-L1 antibody may improve human immunodeficiency virus type 1 (HIV-1)-specific immunity and increase clearance of HIV-1-expressing cells. Methods. We conducted a phase I, randomized, double-blind, placebo-controlled, dose-escalating study of BMS-936559, including HIV-1-infected adults aged >18 to 350 cells/μL and detectable plasma HIV-1 RNA by single-copy assay. Data on single infusions of BMS-936559 (0.3 mg/kg) versus placebo are described. The primary outcomes were safety defined as any grade 3 or greater or immune-related adverse event (AE) and the change in HIV-1 Gag-specific CD8+ T cell responses from baseline to day 28 after infusion. Results. Eight men enrolled: 6 received 0.3 mg/kg of BMS-936559, and 2 received placebo infusions. There were no BMS- 936559-related grade 3 or greater AEs. In 1 participant, asymptomatic hypophysitis (a protocol-defined immune-related AE) was identified 266 days after BMS-936559 infusion; it resolved over time. The mean percentage of HIV-1 Gag-specific CD8+ T cells expressing interferon γ increased from baseline (0.09%) through day 28 (0.20%; P = .14), driven by substantial increases in 2 participants who received BMS-936559. Conclusions. In this first evaluation of an immunologic checkpoint inhibitor in healthy HIV-1-infected persons, single lowdose BMS-936559 infusions appeared to enhance HIV-1-specific immunity in a subset of participants

Lipodystrophy and obesity are associated with decreased number of T cells with regulatory function and pro-inflammatory macrophage phenotype

Background/Objectives:In lipodystrophy (LD) adipose tissue function to store lipids is impaired, leading to metabolic syndrome, similar to that found in obesity. Emerging evidence links dysmetabolism with disorders of the immune system. Our aim is to investigate whether T-cell populations with regulatory function and monocyte-derived macrophages (MDMs) are affected by LD and obesity.Subjects/Methods:Blood was collected from 16 LD, 16 obese (OB, BMI&gt;30 kg m -2) and 16 healthy normal-weight women (CNT). Physical parameters, plasma lipid profile, glucose, HbA1c, leptin levels were determined. Flow cytometry was employed to assess the number of circulating CD4 + /CD25 hi regulatory T cells (Tregs) and invariant natural killer T (iNKT) cells. Characterization of MDMs included: 1. morphological/oil-Red-O staining analyses to define two morphotypes: lipid laden (LL) and spindle-like (sp) MDM; 2. gene expression studies; 3. use of conditioned medium from MDMs (MDMs CM) on human SGBS cells.Results:As compared to CNT, LD and, to a lesser extent, obesity were associated with reduced Tregs and iNKTs (P&lt;0.001 and P&lt;0.01 for LD and OB, respectively), higher number of LL-MDMs (P&lt;0.001 and P&lt;0.01 for LD and OB, respectively), lower number of sp-MDMs (P&lt;0.001 for both LD and OB), which correlated with increased paracrine stimulation of lipid accumulation in cells (P&lt;0.001 and P&lt;0.01 for LD and OB, respectively). LD MDMs showed decreased and increased expression for anti-inflammatory (IL10 and CD163) and pro-inflammatory (CD68 and CCL20) marker genes, respectively. Analysis of correlation indicated that Tregs are directly related with HDL (P&lt;0.01) and inversely related with LL-MDM (P&lt;0.001) and that LL-MDM are directly related with triglycerides (P&lt;0.01) and oxidized LDL (P&lt;0.01).Conclusions:LD and obesity are associated with changes in the immune system: a significant reduction in the number of T cells with regulatory function and a shift of MDM towards lipid accumulation. Lipid profile of the patients correlates with these changes

Randomized clinical trial to assess the impact of the broadly neutralizing HIV-1 monoclonal antibody VRC01 on HIV-1 persistence in individuals on effective ART

Background. Broadly neutralizing monoclonal antibodies (bnMAbs) may promote clearance of HIV-1-expressing cells through antibody-dependent cell-mediated cytotoxicity. We evaluated the effect of the CD4-binding site bnMAb, VRC01, on measures of HIV-1 persistence in chronically infected individuals. Methods. A5342 was a phase 1, randomized, double-blind, placebo-controlled, parallel-arm study. Participants on effective antiretroviral therapy (ART) were randomized to receive 2 infusions of VRC01 (40 mg/kg) at entry and week 3, and 2 infusions of placebo (saline) at weeks 6 and 9; or 2 infusions of placebo at entry and week 3, and 2 infusions of VRC01 at weeks 6 and 9. Results. Infusion of VRC01 was safe and well tolerated. The median fold-change in the cell-associated HIV-1 RNA/DNA ratio from baseline to week 6 was 1.12 and 0.83 for the VRC01 and placebo arms, respectively, with no significant difference between arms (P = .16). There were no significant differences in the proportions with residual plasma viremia ≥1 copies/mL or in phorbol 12-myristate 13-acetate/ionomycin-induced virus production from CD4+ T cells between arms (both P &gt; .05). Conclusions. In individuals with chronic HIV-1 infection on ART, VRC01 infusions were safe and well tolerated but did not affect plasma viremia, cellular HIV-1 RNA/DNA levels, or stimulated virus production from CD4+ T cells

T-cell responses targeting HIV Nef uniquely correlate with infected cell frequencies after long-term antiretroviral therapy

HIV-specific CD8+ T-cell responses limit viral replication in untreated infection. After the initiation of antiretroviral therapy (ART), these responses decay and the infected cell population that remains is commonly considered to be invisible to T-cells. We hypothesized that HIV antigen recognition may persist in ART-treated individuals due to low-level or episodic protein expression. We posited that if persistent recognition were occurring it would be preferentially directed against the early HIV gene products Nef, Tat, and Rev as compared to late gene products, such as Gag, Pol, and Env, which have higher barriers to expression. Using a primary cell model of latency, we observed that a Nef-specific CD8+ T-cell clone exhibited low-level recognition of infected cells prior to reactivation and robust recognition shortly thereafter. A Gag-specific CD8+ T-cell clone failed to recognized infected cells under these conditions, corresponding with a lack of detectable Gag expression. We measured HIV-specific T-cell responses in 96 individuals who had been suppressed on ART for a median of 7 years, and observed a significant, direct correlation between cell-associated HIV DNA levels and magnitudes of IFN-γ-producing Nef/Tat/Rev-specific T-cell responses. This correlation was confirmed in an independent cohort (n = 18). Correlations were not detected between measures of HIV persistence and T-cell responses to other HIV antigens. The correlation with Nef/Tat/Rev-specific T-cells was attributable to Nef-specific responses, the breadth of which also correlated with HIV DNA levels. These results suggest that ongoing Nef expression in ART-treated individuals drives preferential maintenance and/or expansion of T-cells reactive to this protein, implying sensing of infected cells by the immune system. The direct correlation, however, suggests that recognition does not result in efficient elimination of infected cells. These results raise the possibility that enhancing the cytolytic activity of Nef-specific T-cells may lead to reductions in infected cell frequencies, even in the absence of therapeutic latency reversal

No evidence that circulating HIV-specific immune responses contribute to persistent inflammation and immune activation in persons on long-term ART

OBJECTIVE: People with HIV (PWH) have persistently elevated levels of inflammation and immune activation despite suppressive antiretroviral therapy (ART), with specific biomarkers showing associations with non-AIDS-defining morbidities and mortality. We investigated the potential role of the HIV-specific adaptive immune response, which also persists under ART, in driving levels of these clinically relevant biomarkers. DESIGN: Cohort-based study. METHODS: HIV-specific IFN-γ-producing T-cell responses and antibody concentrations were measured in blood at study entry in the ACTG A5321 cohort, following a median of 7 years of suppressive ART. HIV persistence measures including cell-associated (CA)-DNA, CA-RNA, and plasma HIV RNA (single-copy assay) were also assessed at study entry. Plasma inflammatory biomarkers and T-cell activation and cycling were measured at a pre-ART time point and at study entry. RESULTS: Neither the magnitudes of HIV-specific T-cell responses nor HIV antibody levels were correlated with levels of the inflammatory or immune activation biomarkers, including hs-CRP, IL-6, neopterin, sCD14, sCD163, TNF-α, %CD38+HLA-DR+ CD8+ and CD4+ cells, and %Ki67+ CD8+ and CD4+ cells - including after adjustment for pre-ART biomarker level. Plasma HIV RNA levels were modestly correlated with CD8+ T-cell activation (r = 0.25, p = 0.027), but other HIV persistence parameters were not associated with these biomarkers. In mediation analysis, relationships between HIV persistence parameters and inflammatory biomarkers were not influenced by either HIV-specific T-cell responses or antibody levels. CONCLUSIONS: Adaptive HIV-specific immune responses do not appear to contribute to the elevated inflammatory and immune activation profile in persons on long-term ART

The latency reversing agent HODHBt synergizes with IL-15 to enhance cytotoxic function of HIV-specific CD8+ T-cells

IL-15 is under clinical investigation towards the goal of curing HIV infection, due to its abilities to reverse HIV latency and enhance immune effector function. However, increased potency through combination with other agents may be needed. 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) enhances IL-15-mediated latency reversal and NK function, by increasing STAT5 activation. We hypothesized that HODHBt would also synergize with IL-15, via STAT5, to directly enhance HIV-specific cytotoxic T-cell responses. We show that ex vivo IL-15+HODHBt treatment markedly enhances HIV-specific granzyme B-releasing T-cell responses in PBMCs from ARV-suppressed donors. We also observed upregulation of antigen processing and presentation in CD4+ T-cells, and increased surface MHC-I. In ex vivo PBMCs, IL-15+HODHBt was sufficient to reduce intact proviruses in 1 of 3 ARV-suppressed donors. Our findings reveal the potential for 2nd-generation IL-15 studies incorporating HODHBt-like therapeutics. Iterative studies layering on additional latency reversal or other agents are needed to achieve consistent ex vivo reservoir reductions