scholarly journals Potential of the NKG2D/NKG2DL Axis in NK Cell-Mediated Clearance of the HIV-1 Reservoir

2019 ◽  
Vol 20 (18) ◽  
pp. 4490 ◽  
Author(s):  
Maria G. Desimio ◽  
Daniela A. Covino ◽  
Margherita Doria
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Nk Cell ◽  
Ex Vivo ◽  
Virus Reactivation ◽  
Major Drawback ◽  
Virus Eradication ◽  
Latent Hiv ◽  
Hiv 1

Viral persistency in latently infected CD4+ T cells despite antiretroviral therapy (ART) represents a major drawback in the fight against HIV-1. Efforts to purge latent HIV-1 have been attempted using latency reversing agents (LRAs) that activate expression of the quiescent virus. However, initial trials have shown that immune responses of ART-treated patients are ineffective at clearing LRA-reactivated HIV-1 reservoirs, suggesting that an adjuvant immunotherapy is needed. Here we overview multiple lines of evidence indicating that natural killer (NK) cells have the potential to induce anti-HIV-1 responses relevant for virus eradication. In particular, we focus on the role of the NKG2D activating receptor that crucially enables NK cell-mediated killing of HIV-1-infected cells. We describe recent data indicating that LRAs can synergize with HIV-1 at upregulating ligands for NKG2D (NKG2DLs), hence sensitizing T cells that exit from viral latency for recognition and lysis by NK cells; in addition, we report in vivo and ex vivo data showing the potential benefits and drawbacks that LRAs may have on NKG2D expression and, more in general, on the cytotoxicity of NK cells. Finally, we discuss how the NKG2D/NKG2DLs axis can be exploited for the development of effective HIV-1 eradication strategies combining LRA-induced virus reactivation with recently optimized NK cell-based immunotherapies.

scholarly journals TLR1/2 Agonist Enhances Reversal of HIV-1 Latency and Promotes NK Cell-Induced Suppression of HIV-1-Infected Autologous CD4 + T Cells

2021 ◽  
Author(s):  
Siqin Duan ◽  
Xinfeng Xu ◽  
Jinshen Wang ◽  
Liwen Huang ◽  
Jie Peng ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nk Cell ◽  
Ex Vivo ◽  
Shock And Kill ◽  
Infected Cells ◽  
Hiv 1

The complete eradication of human immunodeficiency virus type 1 (HIV-1) is blocked by latent reservoirs in CD4 + T cells and myeloid lineage cells. Toll-like receptors (TLRs) can induce the reversal of HIV-1 latency and trigger the innate immune response. To the best of our knowledge, there is little evidence show the “killing” effect of TLR1/2 agonists but only with a small “shock” potential. To identify a new approach for eradicating the HIV latent reservoir, we evaluated the effectiveness of SMU-Z1, a novel TLR1/2 small molecule agonist, in the “shock and kill” strategy. The results showed that SMU-Z1 can not only enhance latent HIV-1 transcription in ex vivo peripheral blood mononuclear cells (PBMCs) from aviremic HIV-1-infected donors receiving combined antiretroviral therapy (cART) but also in cells of myeloid-monocytic origin in vitro targeting the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. Interestingly, activation marker CD69 was significantly upregulated in NK cells, B cells, and monocytes 48 hours after SMU-Z1 treatment. Furthermore, SMU-Z1 was able to activate T cells without global T cell activation, as well as increase NK cell degranulation and interferon-gamma (IFN-γ) production which further block HIV-1-infected CD4 lymphocytes. In summary, the present study found that SMU-Z1 can both enhance HIV-1 transcription and promote NK cell-mediated inhibition of HIV-1-infected autologous CD4 + T cells. These findings indicate that novel TLR1/2 agonist SMU-Z1 is a promising latency-reversing agent (LRA) for eradication of HIV-1 reservoirs. IMPORTANCE Multiple in vivo studies have shown that many LRAs implemented in the “shock and kill” approach could activate viral transcription but could not induce “killing” effectively. Therefore, a dual function LRA is needed for elimination of HIV-1 reservoirs. We previously developed a small molecule TLR1/2 agonist, SMU-Z1, and demonstrated that it could upregulate NK cells and CD8 + T cells with immune adjuvant and anti-tumor properties in vivo . In the present study, SMU-Z1 can activate innate immune cells without global T cell activation, induce production of proinflammatory and antiviral cytokines, and enhance the cytotoxic function of NK cells. We showed that SMU-Z1 displayed dual potential ex vivo in the “shock” of exposure of HIV-1 latently infected cells and in the “kill” of clearance of infected cells, which is critical for effective use in combination with therapeutic vaccines or broadly neutralizing antibody treatments aimed at curing AIDS.

Assessment of PD-1 expression in human resting and activated natural killer cells and murine tumor models.

2019 ◽  
Vol 37 (8_suppl) ◽  
pp. 36-36
Author(s):  
Sean J. Judge ◽  
Cordelia Dunai ◽  
Ian R. Sturgill ◽  
Kevin M. Stoffel ◽  
William J. Murphy ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Ex Vivo ◽  
Fold Increase ◽  
Wild Type ◽  
Immunodeficient Mice

36 Background: Blockade of the PD-1/PD-L1/2 axis has revolutionized cancer therapy. Although reinvigorated PD-1+ T cells are the main effectors in the response to checkpoint blockade, the contribution of Natural Killer (NK) cells to PD-1/PD-L1 inhibition is under debate. While PD-1 has been identified on NK cells, this appears to be restricted to small populations under limited conditions. We sought to evaluate the extent of PD-1 expression in mouse and human resting and activated NK cells. Methods: Human NK cells were isolated from healthy donor PBMCs and cancer patients. Ex vivo activation and proliferation techniques included recombinant human cytokine and feeder line co-culture. Murine NK cells were isolated from splenocytes, and PBMCs from wild type and immunodeficient mice. We assessed NK cell surface markers and intracellular cytokine by flow cytometry, and gene expression by quantitative RT-PCR. Results: Over 21-days of ex vivo expansion, expression of PD-1 or PD-L1 on human NK cells was < 1% at all time points, while TIGIT+ expression increased to > 85%. Conversely, ConA stimulation of T cells increased PD-1 expression with no change in TIGIT expression. QRT-PCR demonstrated absent PD-1 expression in purified NK cells compared to a 5-fold increase in PD-1 gene expression in ConA stimulated PBMCs. PD-1/PD-L1 was also < 1% in the NK92 cell line and < 2.5% in peripheral CD56+CD3- NK cells from patients with soft tissue sarcoma (STS). NK cells from digested freshly resected STS show variable PD-1 ( < 10%) and minimal PD-L1 ( < 1%) expression with a small, but measurable population of intra-tumoral NK cells (1% of immune cells). In vivo mouse studies showed < 5% PD-1+ NK cells in spleen and tumor of CT26 tumor-bearing mice, while PD-L1+ NK cells increased in frequency from spleen (5-35%) to tumor (40-95%) in both wild type BALB/C and SCID mice. Conclusions: In contrast to prior studies, we did not observe a substantial PD-1+ population on human or murine NK cells after multiple activation strategies compared to T cells. Contrary to its application in T cells, our data suggest that PD-1 is not a useful marker for NK cell exhaustion/dysfunction. PD-L1 on NK cells may represent an important link between NK and T cell immunotherapy.

scholarly journals Identification of Celastrol as a novel HIV-1 Latency Reversal Agent by an Image-Based Screen

2020 ◽  
Author(s):  
Hongbing Liu ◽  
Pei-Wen Hu ◽  
Julien Dubrulle ◽  
Fabio Stossi ◽  
Bryan C. Nikolai ◽  
...  
Keyword(s):  
T Cells ◽  
Ex Vivo ◽  
Research Effort ◽  
Viral Reservoir ◽  
Reversal Agent ◽  
Reversal Agents ◽  
Healthy Donors ◽  
Latent Hiv ◽  
Hiv 1

AbstractAlthough current antiretroviral therapies (ART) are successful in controlling HIV-1 infection, a stable viral reservoir reactivates when ART is discontinued. Consequently, there is a major research effort to develop approaches to disrupt the latent viral reservoir and enhance the immune system’s ability to clear HIV-1. A number of small molecules, termed latency reversal agents (LRAs), have been identified which can reactivate latent HIV-1 in cell lines and patients’ cells ex vivo. However, clinical trials have suggested that combinations of LRAs will be required to efficiently reactivate HIV-1 in vivo, especially LRAs that act synergistically by functioning through distinct pathways. To identify novel LRAs, we used an image-based assay to screen a natural compound library for the ability to induce a low level of aggregation of resting primary CD4+ T cells from healthy donors. We identified celastrol as a novel LRA. Celastrol functions synergistically with other classes of LRA to reactivate latent HIV-1 in a Jurkat cell line, suggesting a novel mechanism in its LRA activity. Additionally, celastrol does not appear to activate resting CD4+ T cells at levels at which it can reactivate latent HIV-1. Celastrol appears to represent a novel class of LRAs and it therefore can serve as a lead compound for LRA development.

IL-15 Administration to In-Vivo Expand Adoptively Transferred NK Cells In Rhesus Macaques

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 960-960
Author(s):  
Rebecca Lopez ◽  
Stephanie Sellers ◽  
Cynthia E. Dunbar ◽  
Richard Childs
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Nk Cells ◽  
Nk Cell ◽  
Ex Vivo ◽  
Rhesus Macaques ◽  
Cell Transfer ◽  
Regulatory Phenotype

Abstract Abstract 960 Immunotherapy using natural killer (NK) cells is currently being explored as a treatment option for patients with advanced malignant diseases. Although pilot clinical trials have shown adoptive NK cell transfer can result in tumor regression in humans with cancer, additional insight from animal models is needed to optimize methods to enhance the function and in vivo persistence of these adoptively infused lymphocytes. In contrast to mice, rhesus macaques have orthologues to most of the human MHC class I and II genes and possess NK cells expressing KIRs that are phenotypically and functionally similar to human NK cells, thus providing an excellent model to evaluate adoptive NK cell therapy. To characterize their in vivo longevity and tissue trafficking following adoptive infusion, we developed a method to expand large numbers of rhesus NK cells in vitro. NK cells enriched from peripheral blood mononuclear cells by depleting CD3+ cells using immunomagnetic beads were expanded in vitro with autologous plasma and a human EBV-LCL feeder cell line using culture conditions identical to those used for human NK cell expansion. Expanded rhesus NK cells were both phenotypically and genotypically similar to their human counterparts; NK cell cultures expanded up to 1000 fold within 2–3 weeks, were greater than 99% CD3 negative, and had a large proportion of CD16/CD56 double positive cells. In addition, expanded NK cells up-regulated receptors involved in tumor killing, including NKG2D, Granzyme B, TRAIL and Fas-ligand and were highly cytotoxic to K562 cells. Adoptive transfer of (3.2×107 – 1×108) CFSE-labeled ex vivo expanded rhesus NK cells has been well tolerated without any overt toxicities noted to date. Remarkably, despite the infusion of large cell numbers, CFSE labeled NK cells were detectable in the peripheral blood, lymph nodes, and bone marrow compartments at very low levels for only a few hours following infusion. Combining adoptive transfer of ex vivo expanded NK cells with IL-15 administration (rhesus recombinant IL-15 10 ug/kg s.c. × 5 days) resulted in only a minimal and transient 24 hour increase in the number of detectable CFSE labeled NK cells in the circulation and bone marrow. Although IL-15 administration did not substantially expand the number of circulating CFSE labeled NK cells that were adoptively transferred, it did result in a substantial increase in circulating numbers of endogenous NK and T-cells (4.74 fold and 5.2 fold increase in CD3-/CD56+ NK cells and CD3+ T-cells respectively). Surprisingly, IL-15 administration also resulted in a significant expansion of circulating T-regs (CD4-/CD25+/CD127Dim/FOXP3 +) which have previously been shown to suppress NK cell effector function in vitro and vivo; T-cells with a regulatory phenotype expanded 4.54 fold. Expansion of circulating T-regs occurred both when IL-15 was administered alone or in conjunction with adoptive NK cell transfer. Conclusions: IL-15 administration in macaques at the doses used in this study did not expand circulating numbers of adoptively transferred ex-vivo expanded NK cells, although it did significantly expand the numbers of circulating endogeneous NK cells. Remarkably, IL-15 administration was also associated with a significant expansion of T-cells with a regulatory phenotype. We are currently evaluating whether lympho-depletion followed by adoptive NK cell transfer can be used as a method to prevent the expansion of T-regs associated with IL-15 administration. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Induction of HIV-1 latency and reactivation in primary memory CD4+ T cells

Blood ◽  
2009 ◽  
Vol 113 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Alberto Bosque ◽  
Vicente Planelles
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Ex Vivo ◽  
Virus Reactivation ◽  
Activated T Cells ◽  
Virus Eradication ◽  
Cis Acting ◽  
Latently Infected ◽  
Memory Cd4 T Cells ◽  
Hiv 1

AbstractThe use of antiretroviral therapy in HIV type 1 (HIV-1)–infected patients does not lead to virus eradication. This is due, to a significant degree, to the fact that HIV-1 can establish a highly stable reservoir of latently infected cells. In this work, we describe an ex vivo experimental system that generates high levels of HIV-1 latently infected memory cells using primary CD4+ T cells. Using this model, we were able to dissect the T cell–signaling pathways and to characterize the long terminal repeat (LTR) cis-acting elements involved in reactivation of HIV-1 in memory CD4+ T cells. We conclude that Lck and nuclear factor of activated T cells (NFAT), but not NF-κB, are required for optimal latent virus reactivation in memory T cells. We also found that the cis-acting elements which are critical toward HIV-1 reactivation are the Sp1 and κB/NFAT transcription factor binding sites.

scholarly journals Identification of celastrol as a novel HIV-1 latency reversal agent by an image-based screen

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0244771
Author(s):  
Hongbing Liu ◽  
Pei-Wen Hu ◽  
Julien Dubrulle ◽  
Fabio Stossi ◽  
Bryan C. Nikolai ◽  
...  
Keyword(s):  
T Cells ◽  
Ex Vivo ◽  
Research Effort ◽  
Viral Reservoir ◽  
Reversal Agent ◽  
Reversal Agents ◽  
Healthy Donors ◽  
Latent Hiv ◽  
Hiv 1

Although current antiretroviral therapies (ART) are successful in controlling HIV-1 infection, a stable viral reservoir reactivates when ART is discontinued. Consequently, there is a major research effort to develop approaches to disrupt the latent viral reservoir and enhance the immune system’s ability to clear HIV-1. A number of small molecules, termed latency reversal agents (LRAs), have been identified which can reactivate latent HIV-1 in cell lines and patients’ cells ex vivo. However, clinical trials have suggested that combinations of LRAs will be required to efficiently reactivate HIV-1 in vivo, especially LRAs that act synergistically by functioning through distinct pathways. To identify novel LRAs, we used an image-based assay to screen a natural compound library for the ability to induce a low level of aggregation of resting primary CD4+ T cells from healthy donors. We identified celastrol as a novel LRA. Celastrol functions synergistically with other classes of LRA to reactivate latent HIV-1 in a Jurkat cell line, suggesting a novel mechanism in its LRA activity. Additionally, celastrol does not appear to activate resting CD4+ T cells at levels at which it can reactivate latent HIV-1. Celastrol appears to represent a novel class of LRAs and it therefore can serve as a lead compound for LRA development.

scholarly journals NK cells acquire PD-1 from the membrane of tumor cells

2020 ◽  
Author(s):  
M.S. Hasim ◽  
E. Vulpis ◽  
G. Sciumè ◽  
H.Y. Shih ◽  
A. Scheer ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Ex Vivo ◽  
Cell Functions ◽  
Cell Responses ◽  
Checkpoint Receptors ◽  
Cancer Immunosurveillance

AbstractNK cells are key effectors of cancer immunosurveillance and immunotherapy and yet, much is still unknown about how cancer evades NK cell responses. Recent studies showed that checkpoint receptors, including PD-1, inhibit NK cell functions, but the mechanisms underlying the expression of these receptors remains unknown. Here, using two mouse models of leukemia, we show that NK cells, rather than intrinsically expressing the protein, are decorated with exogenous PD-1 by acquisition of membrane fragments from tumor cells. PD-1 acquisition, both ex vivo and in vivo, was a feature not only of NK cells, but also of CD8+ T cells. PD-1 acquisition occurred with a mechanism consistent with trogocytosis and did not require engagement of PD-1-ligands on NK cells. In vivo results were corroborated in humans, where PD-1+ NK cells from multiple myeloma patients also stained for cancer cell markers. Our results, in addition to shedding light on a previously unappreciated mechanism underlying the presence of PD-1 on NK and T cells, reveal the immuno-regulatory effect of membrane transfer occurring when immune cells contact tumor cells.

scholarly journals Anti-tumor effects of RTX-240: an engineered red blood cell expressing 4-1BB ligand and interleukin-15

2021 ◽  
Author(s):  
Shannon L. McArdel ◽  
Anne-Sophie Dugast ◽  
Maegan E. Hoover ◽  
Arjun Bollampalli ◽  
Enping Hong ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Blood Cell ◽  
Nk Cells ◽  
Red Blood Cell ◽  
Safety Profile ◽  
Nk Cell ◽  
Cell Activity ◽  
In Vivo Studies

AbstractRecombinant agonists that activate co-stimulatory and cytokine receptors have shown limited clinical anticancer utility, potentially due to narrow therapeutic windows, the need for coordinated activation of co-stimulatory and cytokine pathways and the failure of agonistic antibodies to recapitulate signaling by endogenous ligands. RTX-240 is a genetically engineered red blood cell expressing 4-1BBL and IL-15/IL-15Rα fusion (IL-15TP). RTX-240 is designed to potently and simultaneously stimulate the 4-1BB and IL-15 pathways, thereby activating and expanding T cells and NK cells, while potentially offering an improved safety profile through restricted biodistribution. We assessed the ability of RTX-240 to expand and activate T cells and NK cells and evaluated the in vivo efficacy, pharmacodynamics and tolerability using murine models. Treatment of PBMCs with RTX-240 induced T cell and NK cell activation and proliferation. In vivo studies using mRBC-240, a mouse surrogate for RTX-240, revealed biodistribution predominantly to the red pulp of the spleen, leading to CD8 + T cell and NK cell expansion. mRBC-240 was efficacious in a B16-F10 melanoma model and led to increased NK cell infiltration into the lungs. mRBC-240 significantly inhibited CT26 tumor growth, in association with an increase in tumor-infiltrating proliferating and cytotoxic CD8 + T cells. mRBC-240 was tolerated and showed no evidence of hepatic injury at the highest feasible dose, compared with a 4-1BB agonistic antibody. RTX-240 promotes T cell and NK cell activity in preclinical models and shows efficacy and an improved safety profile. Based on these data, RTX-240 is now being evaluated in a clinical trial.

scholarly journals DNAM-1 promotes activation of cytotoxic lymphocytes by nonprofessional antigen-presenting cells and tumors

2008 ◽  
Vol 205 (13) ◽  
pp. 2965-2973 ◽  
Author(s):  
Susan Gilfillan ◽  
Christopher J. Chan ◽  
Marina Cella ◽  
Nicole M. Haynes ◽  
Aaron S. Rapaport ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Adhesion Molecules ◽  
Cd8 T Cells ◽  
Nk Cell ◽  
Cd8 T Cell ◽  
Antigen Presenting

Natural killer (NK) cells and CD8 T cells require adhesion molecules for migration, activation, expansion, differentiation, and effector functions. DNAX accessory molecule 1 (DNAM-1), an adhesion molecule belonging to the immunoglobulin superfamily, promotes many of these functions in vitro. However, because NK cells and CD8 T cells express multiple adhesion molecules, it is unclear whether DNAM-1 has a unique function or is effectively redundant in vivo. To address this question, we generated mice lacking DNAM-1 and evaluated DNAM-1–deficient CD8 T cell and NK cell function in vitro and in vivo. Our results demonstrate that CD8 T cells require DNAM-1 for co-stimulation when recognizing antigen presented by nonprofessional antigen-presenting cells; in contrast, DNAM-1 is dispensable when dendritic cells present the antigen. Similarly, NK cells require DNAM-1 for the elimination of tumor cells that are comparatively resistant to NK cell–mediated cytotoxicity caused by the paucity of other NK cell–activating ligands. We conclude that DNAM-1 serves to extend the range of target cells that can activate CD8 T cell and NK cells and, hence, may be essential for immunosurveillance against tumors and/or viruses that evade recognition by other activating or accessory molecules.

scholarly journals Interferon Alpha Enhances NK Cell Function and the Suppressive Capacity of HIV-Specific CD8+T Cells

2018 ◽  
Vol 93 (3) ◽  
Author(s):  
Abena K. R. Kwaa ◽  
Chloe A. G. Talana ◽  
Joel N. Blankson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Effector Cell ◽  
Cell Function ◽  
Nk Cell ◽  
Suppressive Capacity ◽  
Short Course ◽  
Shock And Kill ◽  
Hiv 1

ABSTRACTCurrent shock-and-kill strategies for the eradication of the HIV-1 reservoir have resulted in blips of viremia but not in a decrease in the size of the latent reservoir in patients on suppressive antiretroviral therapy (ART). This discrepancy could potentially be explained by an inability of the immune system to kill HIV-1-infected cells following the reversal of latency. Furthermore, some studies have suggested that certain latency-reversing agents (LRAs) may inhibit CD8+T cell and natural killer (NK) cell responses. In this study, we tested the hypothesis that alpha interferon (IFN-α) could improve the function of NK cells from chronic progressors (CP) on ART. We show here that IFN-α treatment enhanced cytokine secretion, polyfunctionality, degranulation, and the cytotoxic potential of NK cells from healthy donors (HD) and CP. We also show that this cytokine enhanced the viral suppressive capacity of NK cells from HD and elite controllers or suppressors. Furthermore, IFN-α enhanced global CP CD8+T cell cytokine responses and the suppressive capacity of ES CD8+T cells. Our data suggest that IFN-α treatment may potentially be used as an immunomodulatory agent in HIV-1 cure strategies.IMPORTANCEData suggest that HIV+individuals unable to control infection fail to do so due to impaired cytokine production and/cytotoxic effector cell function. Consequently, the success of cure agendas such as the shock-and-kill strategy will probably depend on enhancing patient effector cell function. In this regard, NK cells are of particular interest since they complement the function of CD8+T cells. Here, we demonstrate the ability of short-course alpha interferon (IFN-α) treatments to effectively enhance such effector functions in chronic progressor NK cells without inhibiting their general CD8+T cell function. These results point to the possibility of exploring such short-course IFN-α treatments for the enhancement of effector cell function in HIV+patients in future cure strategies.

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