scholarly journals The combination of venetoclax and ixazomib selectively and efficiently kills HIV infected cell lines, but has unacceptable toxicity in primary cell models

2021 ◽  
Author(s):  
Alecia Alto ◽  
Sekar Natesampillai ◽  
Aswath P. Chandrasekar ◽  
Ashton Krogman ◽  
Anisha Misra ◽  
...  

The anti-apoptotic protein BCL2 inhibits death of HIV-infected cells. Previously, we have shown that the BCL2 inhibitor venetoclax selectively kills acutely HIV-infected cells and reduces HIV DNA in latently infected CD4 T cells ex vivo after reactivation with αCD3/αCD28. However, there is a need to identify a combination therapy with venetoclax and a clinically relevant latency reversal agent. Ixazomib is an oral proteasome inhibitor which we have shown reactivates latent HIV and predisposes reactivated cells to cell death. Here, we determined that the combination of venetoclax and ixazomib kills more latently HIV-infected cells and leads to greater reduction in HIV replication compared to either treatment alone in vitro in a T cell model. However, combination treatment of ex vivo CD4 T cells from ART-suppressed, HIV-positive participants resulted in unanticipated and unacceptable non-specific toxicity in primary cells. Therefore, while we show proof of concept that multiple agents can enhance selective killing of HIV infected cells, the combination of venetoclax and ixazomib has unacceptable toxicity in primary cells, and so further investigation is needed to identify a clinically relevant latency reversal agent to combine with venetoclax as a novel strategy to reduce the size of the HIV reservoir. IMPORTANCE: A cure for HIV would require eliminating cells that contain the virus in a latent form from the body. Current antiretroviral medications are unable to rid the body of latently infected cells. Here we show that a combination of investigational agents – ixazomib plus venetoclax- which reactivate latent virus, and predispose infected cells to apoptosis, may reduce latent virus in a T cell model, but at the expense of non-specific toxicity in primary cells.

2019 ◽  
Vol 37 (8_suppl) ◽  
pp. 30-30
Author(s):  
Patrick C. Gedeon ◽  
Carter M. Suryadevara ◽  
Bryan D. Choi ◽  
John H. Sampson

30 Background: Activated T cells are known to traffic throughout the body including past the blood-brain barrier where they perform routine immune surveillance. Whether activated T cells can be used to enhance the efficacy and delivery of intravenously-administered, immunotherapeutic antibodies has yet to be explored. Methods: To examine efficacy, T cell migration and antibody delivery in vivo, the invasive murine glioma, CT-2A-EGFRvIII, was implanted orthotopically in human CD3 transgenic mice. Cohorts of mice were given vehicle or 1x107 non-specifically activated, syngeneic T cells intravenously. Beginning the subsequent day, groups were treated with daily intravenous infusions of human-CD3-binding, tumor-lysis-inducing bispecific antibody (hEGFRvIII-CD3 bi-scFv) or control bispecific antibody. To block T cell extravasation, cohorts received natalizumab or isotype control via intraperitoneal injection every other day beginning on the day of adoptive cell transfer. T cell migration was assessed using whole body bioluminescence imaging of activated T cells transduced to express firefly luciferase. Bispecific antibody biodistribution was assessed using PET-CT imaging of iodine-124 labeled antibody. Results: Following intravenous administration, ex vivo activated T cells tracked to invasive, syngeneic, orthotopic glioma, reaching maximal levels on average four days following adoptive transfer. Administration of ex vivo activated T cells enhanced bispecific antibody efficacy causing a statistically significant increase in survival (p = 0.007) with 80% long-term survivors. Treatment with the T cell extravasation blocking molecule natalizumab abrogated the increase in efficacy to levels observed in cohorts that did not receive adoptive transfer of activated T cells (p = 0.922). Pre-administration with ex vivo activated T cells produced a statistically significant increase in tumor penetrance of radiolabeled bispecific antibody (p = 0.023). Conclusions: Adoptive transfer of non-specifically activated T cells enhances the efficacy and tumor penetrance of intravenously-administered CD3-binding bispecific antibody.


2015 ◽  
Vol 89 (18) ◽  
pp. 9631-9638 ◽  
Author(s):  
Victoria E. K. Walker-Sperling ◽  
Valerie J. Cohen ◽  
Patrick M. Tarwater ◽  
Joel N. Blankson

ABSTRACTThe “shock and kill” model of human immunodeficiency virus type 1 (HIV-1) eradication involves the induction of transcription of HIV-1 genes in latently infected CD4+T cells, followed by the elimination of these infected CD4+T cells by CD8+T cells or other effector cells. CD8+T cells may also be needed to control the spread of new infection if residual infected cells are present at the time combination antiretroviral therapy (cART) is discontinued. In order to determine the time frame needed for CD8+T cells to effectively prevent the spread of HIV-1 infection, we examined the kinetics of HIV transcription and virus release in latently infected cells reactivatedex vivo. Isolated resting, primary CD4+T cells from HIV-positive (HIV+) subjects on suppressive regimens were found to upregulate cell-associated HIV-1 mRNA within 1 h of stimulation and produce extracellular virus as early as 6 h poststimulation. In spite of the rapid kinetics of virus production, we show that CD8+T cells from 2 out of 4 viremic controllers were capable of effectively eliminating reactivated autologous CD4+cells that upregulate cell-associated HIV-1 mRNA. The results have implications for devising strategies to prevent rebound viremia due to reactivation of rare latently infected cells that persist after potentially curative therapy.IMPORTANCEA prominent HIV-1 cure strategy termed “shock and kill” involves the induction of HIV-1 transcription in latently infected CD4+T cells with the goal of elimination of these cells by either the cytotoxic T lymphocyte response or other immune cell subsets. However, the cytotoxic T cell response may also be required after curative treatment if residual latently infected cells remain. The kinetics of HIV-1 reactivation indicate rapid upregulation of cell-associated HIV-1 mRNA and a 5-h window between transcription and virus release. Thus, HIV-specific CD8+T cell responses likely have a very short time frame to eliminate residual latently infected CD4+T cells that become reactivated after discontinuation of antiretroviral therapy following potentially curative treatment strategies.


2019 ◽  
Author(s):  
Birgitta Lindqvist ◽  
Sara Svensson Akusjarvi ◽  
Anders Sonnerborg ◽  
Marios Dimitriou ◽  
J. Peter Svensson

Human immunodeficiency virus type 1 (HIV-1) infection is a chronic condition, where viral DNA integrates into the genome. Latently infected cells form a persistent, heterogeneous reservoir. The reservoir that reinstates an active replication comprises only cells with intact provirus that can be reactivated. We confirmed that latently infected cells from patients exhibited active transcription throughout the provirus. To find transcriptional determinants, we characterized the establishment and maintenance of viral latency during proviral chromatin maturation in cultures of primary CD4+ T-cells for four months after ex vivo HIV-1 infection. As heterochromatin (marked with H3K9me3 or H3K27me3) gradually stabilized, the provirus became less accessible with reduced activation potential. In a subset of infected cells, active marks (i.e., H3K27ac) remained detectable, even after prolonged proviral silencing. After T-cell activation, the proviral activation occurred uniquely in cells with H3K27ac-marked proviruses. Our observations suggested that, after transient proviral activation, cells were actively returned to latency.


2019 ◽  
Author(s):  
Mateusz Stoszko ◽  
Abdullah M.S. Al-Hatmi ◽  
Anton Skriba ◽  
Michael Roling ◽  
Enrico Ne ◽  
...  

AbstractA leading pharmacological strategy towards HIV cure requires “shock” or activation of HIV gene expression in latently infected cells with Latency Reversal Agents (LRAs) followed by their subsequent clearance. In a screen for novel LRAs we used fungal secondary metabolites (extrolites) as a source of bio-active molecules. Using orthogonal mass spectrometry (MS) coupled to latency reversal bioassays, we identified gliotoxin (GTX) as a novel LRA. GTX significantly induced HIV-1 gene expression in latent ex vivo infected primary cells and in CD4+ T cells from all aviremic HIV-1+ participants. RNA sequencing identified 7SK RNA, the scaffold of the P-TEFb inhibitory 7SK snRNP complex to be significantly reduced upon GTX treatment of independent donor CD4+T cells. GTX disrupted 7SK snRNP, releasing active P-TEFb, which then phosphorylated RNA Pol II CTD, inducing HIV transcription. Our data highlight the power of combining a medium throughput bioassay, mycology and orthogonal mass spectrometry to identify novel potentially therapeutic compounds.


2020 ◽  
Author(s):  
Yanqin Ren ◽  
Szu Han Huang ◽  
Amanda B. Macedo ◽  
Adam R. Ward ◽  
Winiffer D. Conce Alberto ◽  
...  

AbstractHIV persists, despite antiviral immune responses and effective antiretroviral therapy, in viral reservoirs that seed rebound viremia if therapy is interrupted. Previously, we showed that the BCL-2 protein contributes to HIV persistence by conferring a survival advantage to reservoir-harboring cells. Here, we demonstrate that many of the BCL-2 family members are overexpressed in HIV-infected CD4+ T-cells, indicating increased tension between pro-apoptotic and pro-survival family members – as well as raising the possibility that the inhibition of pro-survival members may disproportionately affect the survival of HIV-infected cells. Based on these results, we chose to further study BCL2L1 (encoding the protein BCL-XL), due to its consistent overexpression and the availability of selective antagonists. Infection of primary CD4+ T-cells with either a clinical isolate, a CCR5-tropic strain, or a CXCR4-tropic strain of HIV resulted in increased BCL-XL protein expression; and treatment with two selective BCL-XL antagonists, A-1155463 and A-1551852, led to disproportionate cell death compared to uninfected CD4+ T-cells. In a primary cell model of latency, both BCL-XL antagonists drove significant reductions in total HIV DNA and in infectious cell frequencies both alone and in combination with the latency reversing agent bryostatin-1, with little off-target cytotoxicity. However, these antagonists, with or without bryostatin-1, or in combination with the highly potent latency reversing agent combination PMA + ionomycin, failed to reduce total HIV DNA and infectious reservoirs in ex vivo CD4+ T-cells from ART-suppressed donors. Our results add to growing evidence that bonafide reservoir-harboring cells are resistant to multiple “kick and kill” modalities - relative to latency models - and uncover BCL-XL antagonists as a facile approach to probing mechanistic underpinnings. We also interpret our results as encouraging of further exploration of BCL-XL antagonists for cure, where combination approaches may unlock the ability to eliminate ex vivo reservoirs.


2010 ◽  
Vol 84 (13) ◽  
pp. 6425-6437 ◽  
Author(s):  
Mudit Tyagi ◽  
Richard John Pearson ◽  
Jonathan Karn

ABSTRACT The development of suitable experimental systems for studying HIV latency in primary cells that permit detailed biochemical analyses and the screening of drugs is a critical step in the effort to develop viral eradication strategies. Primary CD4+ T cells were isolated from peripheral blood and amplified by antibodies to the T-cell receptor (TCR). The cells were then infected by lentiviral vectors carrying fluorescent reporters and either the wild-type Tat gene or the attenuated H13L Tat gene. After sorting for the positive cells and reamplification, the infected cells were allowed to spontaneously enter latency by long-term cultivation on the H80 feeder cell line in the absence of TCR stimulation. By 6 weeks almost all of the cells lost fluorescent protein marker expression; however, more than 95% of these latently infected cells could be reactivated after stimulation of the TCR by α-CD3/CD28 antibodies. Chromatin immunoprecipitation assays showed that, analogously to Jurkat T cells, latent proviruses in primary CD4+ T cells are enriched in heterochromatic markers, including high levels of CBF-1, histone deacetylases, and methylated histones. Upon TCR activation, there was recruitment of NF-κB to the promoter and conversion of heterochromatin structures present on the latent provirus to active euchromatin structures containing acetylated histones. Surprisingly, latently infected primary cells cannot be induced by tumor necrosis factor alpha because of a restriction in P-TEFb levels, which can be overcome by activation of the TCR. Thus, a combination of restrictive chromatin structures at the HIV long terminal repeat and limiting P-TEFb levels contribute to transcriptional silencing leading to latency in primary CD4+ T cells.


2019 ◽  
Vol 93 (10) ◽  
Author(s):  
George N. Llewellyn ◽  
Eduardo Seclén ◽  
Stephen Wietgrefe ◽  
Siyu Liu ◽  
Morgan Chateau ◽  
...  

ABSTRACTCombination anti-retroviral drug therapy (ART) potently suppresses HIV-1 replication but does not result in virus eradication or a cure. A major contributing factor is the long-term persistence of a reservoir of latently infected cells. To study this reservoir, we established a humanized mouse model of HIV-1 infection and ART suppression based on an oral ART regimen. Similar to humans, HIV-1 levels in the blood of ART-treated animals were frequently suppressed below the limits of detection. However, the limited timeframe of the mouse model and the small volume of available samples makes it a challenging model with which to achieve full viral suppression and to investigate the latent reservoir. We therefore used anex vivolatency reactivation assay that allows a semiquantitative measure of the latent reservoir that establishes in individual animals, regardless of whether they are treated with ART. Using this assay, we found that latently infected human CD4 T cells can be readily detected in mouse lymphoid tissues and that latent HIV-1 was enriched in populations expressing markers of T cell exhaustion, PD-1 and TIGIT. In addition, we were able to use theex vivolatency reactivation assay to demonstrate that HIV-specific TALENs can reduce the fraction of reactivatable virus in the latently infected cell population that establishesin vivo, supporting the use of targeted nuclease-based approaches for an HIV-1 cure.IMPORTANCEHIV-1 can establish latent infections that are not cleared by current antiretroviral drugs or the body’s immune responses and therefore represent a major barrier to curing HIV-infected individuals. However, the lack of expression of viral antigens on latently infected cells makes them difficult to identify or study. Here, we describe a humanized mouse model that can be used to detect latent but reactivatable HIV-1 in both untreated mice and those on ART and therefore provides a simple system with which to study the latent HIV-1 reservoir and the impact of interventions aimed at reducing it.


2020 ◽  
Author(s):  
V. Gauttier ◽  
A. Morello ◽  
I. Girault ◽  
C. Mary ◽  
L. Belarif ◽  
...  

AbstractThe COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) which enters the body principally through the nasal and larynx mucosa and progress to the lungs through the respiratory tract. SARS-CoV-2 replicates efficiently in respiratory epithelial cells motivating the development of alternative and rapidly scalable vaccine inducing mucosal protective and long-lasting immunity. We have previously developed an immunologically optimized multi-neoepitopes-based peptide vaccine platform which has already demonstrated tolerance and efficacy in hundreds of lung cancer patients. Here, we present a multi-target CD8 T cell peptide COVID-19 vaccine design targeting several structural (S, M, N) and non-structural (NSPs) SARS-CoV-2 proteins with selected epitopes in conserved regions of the SARS-CoV-2 genome. We observed that a single subcutaneous injection of a serie of epitopes induces a robust immunogenicity in-vivo as measured by IFNγ ELIspot. Upon tetramer characterization we found that this serie of epitopes induces a strong proportion of virus-specific CD8 T cells expressing CD103, CD44, CXCR3 and CD49a, the specific phenotype of tissue-resident memory T lymphocytes (Trm). Finally, we observed broad cellular responses, as characterized by IFNγ production, upon restimulation with structural and non-structural protein-derived epitopes using blood T cells isolated from convalescent asymptomatic, moderate and severe COVID-19 patients. These data provide insights for further development of a second generation of COVID-19 vaccine focused on inducing lasting Th1-biased memory CD8 T cell sentinels protection using immunodominant epitopes naturally observed after SARS-CoV-2 infection resolution.Statement of SignificanceHumoral and cellular adaptive immunity are different and complementary immune defenses engaged by the body to clear viral infection. While neutralizing antibodies have the capacity to block virus binding to its entry receptor expressed on human cells, memory T lymphocytes have the capacity to eliminate infected cells and are required for viral clearance. However, viruses evolve quickly, and their antigens are prone to mutations to avoid recognition by the antibodies (phenomenon named ‘antigenic drift’). This limitation of the antibody-mediated immunity could be addressed by the T-cell mediated immunity, which is able to recognize conserved viral peptides from any viral proteins presented by virus-infected cells. Thus, by targeting several proteins and conserved regions on the genome of a virus, T-cell epitope-based vaccines are less subjected to mutations and may work effectively on different strains of the virus. We designed a multi-target T cell-based vaccine containing epitope regions optimized for CD8+ T cell stimulation that would drive long-lasting cellular immunity with high specificity, avoiding undesired effects such as antibody-dependent enhancement (ADE) and antibody-induced macrophages hyperinflammation that could be observed in subjects with severe COVID-19. Our in-vivo results showed that a single injection of selected CD8 T cell epitopes induces memory viral-specific T-cell responses with a phenotype of tissue-resident memory T cells (Trm). Trm has attracted a growing interest for developing vaccination strategies since they act as immune sentinels in barrier tissue such as the respiratory tract and the lung. Because of their localization in tissues, they are able to immediately recognize infected cells and, because of their memory phenotypes, they rapidly respond to viral infection by orchestrating local protective immune responses to eliminate pathogens. Lastly, such multiepitope-based vaccination platform uses robust and well-validated synthetic peptide production technologies that can be rapidly manufactured in a distributed manner.


Author(s):  
Pilar Mendoza ◽  
Julia R. Jackson ◽  
Thiago Oliveira ◽  
Christian Gaebler ◽  
Victor Ramos ◽  
...  

AbstractAntiretroviral therapy suppresses but does not cure HIV-1 infection due to the existence of a long-lived reservoir of latently infected cells. The reservoir has an estimated half-life of 44 months and is largely composed of clones of infected CD4+ T cells. The long half-life appears to result in part from expansion and contraction of infected CD4+ T cell clones. However, the mechanisms that govern this process are poorly understood. To determine whether the clones might result from, and be maintained by exposure to antigen, we measured responses of reservoir cells to a small subset of antigens from viruses that produce chronic or recurrent infections. Despite the limited panel of test antigens, clones of antigen responsive CD4+ T cells containing defective or intact latent proviruses were found in 7 out of 8 individuals studied. Thus, chronic or repeated exposure to antigen may contribute to the longevity of the HIV-1 reservoir by stimulating the clonal expansion of latently infected CD4+ T cells.


2018 ◽  
Vol 92 (20) ◽  
Author(s):  
Alessandra Noto ◽  
Francesco A. Procopio ◽  
Riddhima Banga ◽  
Madeleine Suffiotti ◽  
Jean-Marc Corpataux ◽  
...  

ABSTRACTA recent study conducted in blood has proposed CD32 as the marker identifying the “elusive” HIV reservoir. We have investigated the distribution of CD32+CD4 T cells in blood and lymph nodes (LNs) of HIV-1-uninfected subjects and viremic untreated and long-term-treated HIV-1-infected individuals and their relationship with PD-1+CD4 T cells. The frequency of CD32+CD4 T cells was increased in viremic compared to treated individuals in LNs, and a large proportion (up to 50%) of CD32+cells coexpressed PD-1 and were enriched within T follicular helper (Tfh) cells. We next investigated the role of LN CD32+CD4 T cells in the HIV reservoir. Total HIV DNA was enriched in CD32+and PD-1+CD4 T cells compared to CD32−and PD-1−cells in both viremic and treated individuals, but there was no difference between CD32+and PD-1+cells. There was no enrichment of latently infected cells with inducible HIV-1 in CD32+versus PD-1+cells in antiretroviral therapy (ART)-treated individuals. HIV-1 transcription was then analyzed in LN memory CD4 T cell populations sorted on the basis of CD32 and PD-1 expression. CD32+PD-1+CD4 T cells were significantly enriched in cell-associated HIV RNA compared to CD32−PD-1−(averages of 5.2-fold in treated individuals and 86.6-fold in viremics), CD32+PD-1−(2.2-fold in treated individuals and 4.3-fold in viremics), and CD32−PD-1+(2.2-fold in ART-treated individuals and 4.6-fold in viremics) cell populations. Similar levels of HIV-1 transcription were found in CD32+PD-1−and CD32−PD-1+CD4 T cells. Interestingly, the proportion of CD32+and PD-1+CD4 T cells negatively correlated with CD4 T cell counts and length of therapy. Therefore, the expression of CD32 identifies, independently of PD-1, a CD4 T cell population with persistent HIV-1 transcription and coexpression of CD32 and PD-1, the CD4 T cell population with the highest levels of HIV-1 transcription in both viremic and treated individuals.IMPORTANCEThe existence of long-lived latently infected resting memory CD4 T cells represents a major obstacle to the eradication of HIV infection. Identifying cell markers defining latently infected cells containing replication-competent virus is important in order to determine the mechanisms of HIV persistence and to develop novel therapeutic strategies to cure HIV infection. We provide evidence that PD-1 and CD32 may have a complementary role in better defining CD4 T cell populations infected with HIV-1. Furthermore, CD4 T cells coexpressing CD32 and PD-1 identify a CD4 T cell population with high levels of persistent HIV-1 transcription.


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