Pharmacologic HIV-1 Nef blockade promotes CD8 T cell–mediated elimination of latently HIV-1–infected cells in vitro

Mujib, Shariq; Saiyed, Aamir; Fadel, Saleh; Bozorgzad, Ardalan; Aidarus, Nasra; Yue, Feng Yun; Benko, Erika; Kovacs, Colin; Emert-Sedlak, Lori A.; Smithgall, Thomas E.; Ostrowski, Mario

doi:10.1172/jci.insight.93684

Cited by 31 publications

(38 citation statements)

References 68 publications

(118 reference statements)

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“…Immunological strategies in the field of HIV eradication have focused on HIV-specific cytotoxic T lymphocytes (CTLs) (19)(20)(21), although recently, interest in NK cells has emerged. The capacity of NK cells to produce IFN-␥ and upregulate NKp30 and NKp46 has been inversely associated with viral reservoir size (22), and HIV DNA decline was correlated with NK cell frequency after panobinostat treatment in a clinical study (23), suggesting a role for NK cells in the clearance of HIV infection.…”

Section: Discussionmentioning

confidence: 99%

Interleukin-15-Stimulated Natural Killer Cells Clear HIV-1-Infected Cells following Latency Reversal Ex Vivo

Garrido

Abad-Fernández

Tuyishime

et al. 2018

J Virol

104

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Current efforts toward human immunodeficiency virus (HIV) eradication include approaches to augment immune recognition and elimination of persistently infected cells following latency reversal. Natural killer (NK) cells, the main effectors of the innate immune system, recognize and clear targets using different mechanisms than CD8 T cells, offering an alternative or complementary approach for HIV clearance strategies. We assessed the impact of interleukin 15 (IL-15) treatment on NK cell function and the potential for stimulated NK cells to clear the HIV reservoir. We measured NK cell receptor expression, antibody-dependent cell-mediated cytotoxicity (ADCC), cytotoxicity, interferon gamma (IFN-γ) production, and antiviral activity in autologous HIV replication systems. All NK cell functions were uniformly improved by IL-15, and, more importantly, IL-15-treated NK cells were able to clear latently HIV-infected cells after exposure to vorinostat, a clinically relevant latency-reversing agent. We also demonstrate that NK cells from HIV-infected individuals aviremic on antiretroviral therapy can be efficiently stimulated with IL-15. Our work opens a promising line of investigation leading to future immunotherapies to clear persistent HIV infection using NK cells. In the search for an HIV cure, strategies to enhance immune function to allow recognition and clearance of HIV-infected cells following latency reversal are being evaluated. Natural killer (NK) cells possess characteristics that can be exploited for immunotherapy against persistent HIV infection. We demonstrate that NK cells from HIV-positive donors can be strongly stimulated with IL-15, improving their antiviral and cytotoxic potential and, more importantly, clearing HIV-infected cells after latency reversal with a clinically relevant drug. Our results encourage further investigation to design NK cell-based immunotherapies to achieve HIV eradication.

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Section: Discussionmentioning

confidence: 99%

Interleukin-15-Stimulated Natural Killer Cells Clear HIV-1-Infected Cells following Latency Reversal Ex Vivo

Garrido

Abad-Fernández

Tuyishime

et al. 2018

J Virol

104

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“…4A) and the fact that reservoir size declines very slowly on cART (65)(66)(67), it would require larger cohorts with follow-up times substantially longer than those in the present study (48 weeks only) to adequately assess Nef's additional possible modulatory effects on reservoir decay dynamics during suppressive cART. The observation that pharmacologic inhibition of Nef promoted CD8 ϩ T-cell-mediated elimination of latently HIVinfected cells in vitro (42) supports this notion, and given our study's modest size and follow-up time, we cannot conclusively rule this out. One caveat is that future studies, if undertaken using observational cohorts, would additionally need to control for the duration of cART suppression, a variable that we did not need to consider since ours was a post hoc analysis of a clinical trial where the cART duration was the same for all participants.…”

Section: Discussionmentioning

confidence: 76%

“…As primary nef sequences differ in their ability to downregulate CD4 and, in particular, HLA (36)(37)(38)(39)(40)(41), we hypothesized that individuals harboring nef sequences with a strong immune evasion function would display larger reservoirs due to Nef-mediated protection of infected cells from immune clearance. A role for Nef in maintaining the HIV reservoir is additionally supported by the recent observation that pharmacologic inhibition of Nef promotes CD8 ϩ T-cell-mediated elimination of latently HIV-infected cells in vitro (42).…”

mentioning

confidence: 95%

HIV Subtype and Nef-Mediated Immune Evasion Function Correlate with Viral Reservoir Size in Early-Treated Individuals

Omondi

Chandrarathna

Mujib

et al. 2019

J Virol

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The HIV accessory protein Nef modulates key immune evasion and pathogenic functions, and its encoding gene region exhibits high sequence diversity. Given the recent identification of early HIV-specific adaptive immune responses as novel correlates of HIV reservoir size, we hypothesized that viral factors that facilitate the evasion of such responses—namely, Nef genetic and functional diversity—might also influence reservoir establishment and/or persistence. We isolated baseline plasma HIV RNA-derivednefclones from 30 acute/early-infected individuals who participated in a clinical trial of early combination antiretroviral therapy (cART) (<6 months following infection) and assessed each Nef clone's ability to downregulate CD4 and human leukocyte antigen (HLA) class Iin vitro. We then explored the relationships between baseline clinical, immunological, and virological characteristics and the HIV reservoir size measured 48 weeks following initiation of suppressive cART (where the reservoir size was quantified in terms of the proviral DNA loads as well as the levels of replication-competent HIV in CD4+T cells). Maximal within-host Nef-mediated downregulation of HLA, but not CD4, correlated positively with post-cART proviral DNA levels (Spearman'sR = 0.61,P = 0.0004) and replication-competent reservoir sizes (Spearman'sR = 0.36,P = 0.056) in univariable analyses. Furthermore, the Nef-mediated HLA downregulation function was retained in final multivariable models adjusting for established clinical and immunological correlates of reservoir size. Finally, HIV subtype B-infected persons (n = 25) harbored significantly larger viral reservoirs than non-subtype B-infected persons (2 infected with subtype CRF01_AE and 3 infected with subtype G). Our results highlight a potentially important role of viral factors—in particular, HIV subtype and accessory protein function—in modulating viral reservoir establishment and persistence.IMPORTANCEWhile combination antiretroviral therapies (cART) have transformed HIV infection into a chronic manageable condition, they do not act upon the latent HIV reservoir and are therefore not curative. As HIV cure or remission should be more readily achievable in individuals with smaller HIV reservoirs, achieving a deeper understanding of the clinical, immunological, and virological determinants of reservoir size is critical to eradication efforts. We performed apost hocanalysis of 30 participants of a clinical trial of early cART who had previously been assessed in detail for their clinical, immunological, and reservoir size characteristics. We observed that the HIV subtype and autologous Nef-mediated HLA downregulation function correlated with the viral reservoir size measured approximately 1 year post-cART initiation. Our findings highlight virological characteristics—both genetic and functional—as possible novel determinants of HIV reservoir establishment and persistence.

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“…The original hit compound from this study, known as B9, and a non-azo B9 analog (compound 2 from Emert-Sedlak et al (31); see Figure 7A for structures) bind directly to recombinant HIV-1 Nef in vitro with KD values in the high nM range and inhibit Nef-mediated enhancement of viral infectivity and replication. Both compounds have been shown to restore cell-surface MHC-I to HIV-1-infected CD4 T cells in a Nef-dependent manner, triggering an autologous CTL response in vitro (32). Docking models of both inhibitors with X-ray crystal structures of Nef have suggested that these compounds may recognize a pocket formed by the helical Nef dimer interface (17,31) ( Figure 7A).…”

Section: Small Molecule Nef Inhibitors Block Nef-dependent Itk and Btmentioning

confidence: 99%

HIV-1 Nef dimers short-circuit immune receptor signaling by activating Tec-family kinases at the host cell membrane

Li¹,

Aryal

Shu

et al. 2020

Journal of Biological Chemistry

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The HIV-1 virulence factor Nef promotes high-titer viral replication, immune escape, and pathogenicity. Nef interacts with interleukin-2–inducible T-cell kinase (Itk) and Bruton's tyrosine kinase (Btk), two Tec-family kinases expressed in HIV-1 target cells (CD4 T cells and macrophages, respectively). Using a cell-based bimolecular fluorescence complementation assay, here we demonstrate that Nef recruits both Itk and Btk to the cell membrane and induces constitutive kinase activation in transfected 293T cells. Nef homodimerization-defective mutants retained their interaction with both kinases but failed to induce activation, supporting a role for Nef homodimer formation in the activation mechanism. HIV-1 infection up-regulates endogenous Itk activity in SupT1 T cells and donor-derived peripheral blood mononuclear cells. However, HIV-1 strains expressing Nef variants with mutations in the dimerization interface replicated poorly and were significantly attenuated in Itk activation. We conclude that direct activation of Itk and Btk by Nef at the membrane in HIV-infected cells may override normal immune receptor control of Tec-family kinase activity to enhance the viral life cycle.

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Pharmacologic HIV-1 Nef blockade promotes CD8 T cell–mediated elimination of latently HIV-1–infected cells in vitro

Cited by 31 publications

References 68 publications

Interleukin-15-Stimulated Natural Killer Cells Clear HIV-1-Infected Cells following Latency Reversal Ex Vivo

Interleukin-15-Stimulated Natural Killer Cells Clear HIV-1-Infected Cells following Latency Reversal Ex Vivo

HIV Subtype and Nef-Mediated Immune Evasion Function Correlate with Viral Reservoir Size in Early-Treated Individuals

HIV-1 Nef dimers short-circuit immune receptor signaling by activating Tec-family kinases at the host cell membrane

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