scholarly journals Human antigen-specific memory natural killer cell responses develop against HIV-1 and influenza virus and are dependent on MHC-E restriction

2020 ◽  
Author(s):  
Stephanie Jost ◽  
Olivier Lucar ◽  
Taylor Yoder ◽  
Kyle Kroll ◽  
Sho Sugawara ◽  
...  

ABSTRACTFor over a decade, multiple studies have disputed the notion of natural killer (NK) cells as purely innate lymphocytes by demonstrating that they are capable of putative antigen-specific immunological memory against multiple infectious agents including two critical global health priorities – HIV and influenza. However, the mechanisms underlying antigen specificity remain unknown. Herein, we demonstrate that antigen-specific human NK cell memory develops upon exposure to both HIV and influenza, unified by a conserved and epitope-specific targetable mechanism firmly dependent on the activating CD94/NKG2C receptor and its ligand HLA-E, and confirm these findings by three rigorous and novel assays. We validated the permanent acquisition of antigen-specificity by individual memory NK cells by single-cell cloning. We identified biomarkers of antigen-specific NK cell memory through RNA-Seq transcriptomic fingerprints and complex immunophenotyping by 30-parameter flow cytometry showing elevated expression of KLRG1, α4β7 and NKG2C. Finally, we show individual HLA-E-restricted peptides that may constitute the dominant response in HIV-1- and influenza-infected persons in vivo. Our findings clarify the mechanisms behind formation of antigen-specific memory NK cells, and suggest they could be targeted for future vaccines, cure strategies, or other therapeutic interventions.

2018 ◽  
Vol 115 (45) ◽  
pp. 11579-11584 ◽  
Author(s):  
Andrew Wight ◽  
Ahmad Bakur Mahmoud ◽  
Michal Scur ◽  
Megan M. Tu ◽  
Mir Munir A. Rahim ◽  
...  

Adaptive natural killer (NK) cell memory represents a new frontier in immunology. Work over the last decade has discovered and confirmed the existence of NK cells with antigen-specific memories, which had previously been considered a unique property of T and B cells. These findings have shown that antigen-specific NK cells gain their specificity without the use of RAG proteins, representing a novel mechanism for generating antigen specificity, but the details of this mechanism have remained a mystery. We have discovered that members of the Ly49 family of surface receptors are critically involved in both the sensitization and the challenge phases of an NK cell memory response, as is antigen presentation from their binding partner, the class I MHC. Moreover, we demonstrate that the Ly49-interacting component of a presented antigen dictates the specificity of the NK cell memory response, implicating Ly49 receptors themselves in antigen-specific recognition. Finally, we demonstrate that adaptive NK cell memories can protect against an otherwise lethal melanoma without T cell or B cell support. These findings offer insight into the mechanism behind NK cell antigen specificity and demonstrate the clinical potential of this adaptive immune cell.


Gut ◽  
2020 ◽  
pp. gutjnl-2019-319252 ◽  
Author(s):  
Ratna S Wijaya ◽  
Scott A Read ◽  
Naomi R Truong ◽  
Shuanglin Han ◽  
Dishen Chen ◽  
...  

ObjectiveVaccination against hepatitis B virus (HBV) confers protection from subsequent infection through immunological memory that is traditionally considered the domain of the adaptive immune system. This view has been challenged following the identification of antigen-specific memory natural killer cells (mNKs) in mice and non-human primates. While the presence of mNKs has been suggested in humans based on the expansion of NK cells following pathogen exposure, evidence regarding antigen-specificity is lacking. Here, we demonstrate the existence of HBV-specific mNKs in humans after vaccination and in chronic HBV infection.DesignNK cell responses were evaluated by flow cytometry and ELISA following challenge with HBV antigens in HBV vaccinated, non-vaccinated and chronic HBV-infected individuals.ResultsNK cells from vaccinated subjects demonstrated higher cytotoxic and proliferative responses against autologous hepatitis B surface antigen (HBsAg)-pulsed monocyte-derived dendritic cells (moDCs) compared with unvaccinated subjects. Moreover, NK cell lysis of HBsAg-pulsed moDCs was significantly higher than that of hepatitis B core antigen (HBcAg)-pulsed moDCs (non-vaccine antigen) or tumour necrosis factor α-activated moDCs in a NKG2D-dependent manner. The mNKs response was mediated by CD56dim NK cells coexpressing CD57, CD69 and KLRG1. Further, mNKs from chronic hepatitis B patients exhibited greater degranulation against HBcAg-pulsed moDCs compared with unvaccinated or vaccinated patients. Notably, mNK activity was negatively correlated with HBV DNA levels.ConclusionsOur data support the presence of a mature mNKs following HBV antigen exposure either through vaccination or infection. Harnessing these antigen specific, functionally active mNKs provides an opportunity to develop novel treatments targeting HBV in chronic infection.


2016 ◽  
Vol 213 (12) ◽  
pp. 2745-2758 ◽  
Author(s):  
Tsukasa Nabekura ◽  
Lewis L. Lanier

Natural killer (NK) cells provide important host defense and can generate long-lived memory NK cells. Here, by using novel transgenic mice carrying inducible Cre expressed under the control of Ncr1 gene, we demonstrated that two distinct long-lived NK cell subsets differentiate in a mouse model of cytomegalovirus (MCMV) infection. NK cells expressing the MCMV-specific Ly49H receptor differentiated into memory NK cells by an activating signaling through Ly49H and Ly49H− NK cells differentiated into cytokine-activated NK cells by exposure to inflammatory cytokines during infection. Interleukin-12 is indispensable for optimal generation of both antigen-specific memory NK cells and cytokine-activated NK cells. MCMV-specific memory NK cells show enhanced effector function and augmented antitumor activity in vivo as compared with cytokine-activated NK cells, whereas cytokine-activated NK cells exhibited a more robust response to IL-15 and persisted better in an MCMV-free environment. These findings reveal that NK cells are capable of differentiation into distinct long-lived subsets with different functional properties.


2012 ◽  
Vol 209 (5) ◽  
pp. 947-954 ◽  
Author(s):  
Joseph C. Sun ◽  
Sharline Madera ◽  
Natalie A. Bezman ◽  
Joshua N. Beilke ◽  
Mark H. Kaplan ◽  
...  

Although natural killer (NK) cells are classified as innate immune cells, recent studies demonstrate that NK cells can become long-lived memory cells and contribute to secondary immune responses. The precise signals that promote generation of long-lived memory NK cells are unknown. Using cytokine receptor-deficient mice, we show that interleukin-12 (IL-12) is indispensible for mouse cytomegalovirus (MCMV)-specific NK cell expansion and generation of memory NK cells. In contrast to wild-type NK cells that proliferated robustly and resided in lymphoid and nonlymphoid tissues for months after MCMV infection, IL-12 receptor–deficient NK cells failed to expand and were unable to mediate protection after MCMV challenge. We further demonstrate that a STAT4-dependent IFN-γ–independent mechanism contributes toward the generation of memory NK cells during MCMV infection. Understanding the full contribution of inflammatory cytokine signaling to the NK cell response against viral infection will be of interest for the development of vaccines and therapeutics.


2007 ◽  
Vol 204 (12) ◽  
pp. 3027-3036 ◽  
Author(s):  
Galit Alter ◽  
Maureen P. Martin ◽  
Nickolas Teigen ◽  
William H. Carr ◽  
Todd J. Suscovich ◽  
...  

Decline of peak viremia during acute HIV-1 infection occurs before the development of vigorous adaptive immunity, and the level of decline correlates inversely with the rate of AIDS progression, implicating a potential role for the innate immune response in determining disease outcome. The combined expression of an activating natural killer (NK) cell receptor, the killer immunoglobulin-like receptor (KIR) 3DS1, and its presumed ligand, human leukocyte antigen (HLA)–B Bw4-80I, has been associated in epidemiological studies with a slow progression to AIDS. We examined the functional ability of NK cells to differentially control HIV-1 replication in vitro based on their KIR and HLA types. NK cells expressing KIR3DS1 showed strong, significant dose- and cell contact–dependent inhibition of HIV-1 replication in target cells expressing HLA-B Bw4-80I compared with NK cells that did not express KIR3DS1. Furthermore, KIR3DS1+ NK cells and NKLs were preferentially activated, and lysed HIV-1 infected target cells in an HLA-B Bw4-80I–dependent manner. These data provide the first functional evidence that variation at the KIR locus influences the effectiveness of NK cell activity in the containment of viral replication.


2015 ◽  
Vol 7 (6) ◽  
pp. 557-562 ◽  
Author(s):  
Timothy E. O'Sullivan ◽  
Joseph C. Sun

Immunological memory is classically regarded as an attribute of antigen-specific T and B lymphocytes of the adaptive immune system. Cells of the innate immune system, including natural killer (NK) cells, have been considered short-lived cytolytic cells that can rapidly respond against pathogens in an antigen-independent manner and then die off. However, NK cells have recently been described to possess traits of adaptive immunity, such as clonal expansion after viral antigen exposure to generate long-lived memory cells. In this review, we will discuss the current evidence for viral-induced NK cell memory in both mice and humans.


Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 866
Author(s):  
Baca Chan ◽  
Maja Arapović ◽  
Laura Masters ◽  
Francois Rwandamuiye ◽  
Stipan Jonjić ◽  
...  

As the largest herpesviruses, the 230 kb genomes of cytomegaloviruses (CMVs) have increased our understanding of host immunity and viral escape mechanisms, although many of the annotated genes remain as yet uncharacterised. Here we identify the m15 locus of murine CMV (MCMV) as a viral modulator of natural killer (NK) cell immunity. We show that, rather than discrete transcripts from the m14, m15 and m16 genes as annotated, there are five 3′-coterminal transcripts expressed over this region, all utilising a consensus polyA tail at the end of the m16 gene. Functional inactivation of any one of these genes had no measurable impact on viral replication. However, disruption of all five transcripts led to significantly attenuated dissemination to, and replication in, the salivary glands of multiple strains of mice, but normal growth during acute infection. Disruption of the m15 locus was associated with heightened NK cell responses, including enhanced proliferation and IFNγ production. Depletion of NK cells, but not T cells, rescued salivary gland replication and viral shedding. These data demonstrate the identification of multiple transcripts expressed by a single locus which modulate, perhaps in a concerted fashion, the function of anti-viral NK cells.


Endocrines ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 121-132
Author(s):  
Erik D. Hanson ◽  
Lauren C. Bates ◽  
Kaileigh Moertl ◽  
Elizabeth S. Evans

Natural killer (NK) cells from the innate immune system are integral to overall immunity and also in managing the tumor burden during cancer. Breast (BCa) and prostate cancer (PCa) are the most common tumors in U.S. adults. Both BCa and PCa are frequently treated with hormone suppression therapies that are associated with numerous adverse effects including direct effects on the immune system. Regular exercise is recommended for cancer survivors to reduce side effects and improve quality of life. Acute exercise is a potent stimulus for NK cells in healthy individuals with current evidence indicating that NK mobilization in individuals with BCa and PCa is comparable. NK cell mobilization results from elevations in shear stress and catecholamine levels. Despite a normal NK cell response to exercise, increases in epinephrine are attenuated in BCa and PCa. The significance of this potential discrepancy still needs to be determined. However, alterations in adrenal hormone signaling are hypothesized to be due to chronic stress during cancer treatment. Additional compensatory factors induced by exercise are reviewed along with recommendations on standardized approaches to be used in exercise immunology studies involving oncology populations.


Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2796
Author(s):  
Aicha E. Quamine ◽  
Mallery R. Olsen ◽  
Monica M. Cho ◽  
Christian M. Capitini

Treatment of metastatic pediatric solid tumors remain a significant challenge, particularly in relapsed and refractory settings. Standard treatment has included surgical resection, radiation, chemotherapy, and, in the case of neuroblastoma, immunotherapy. Despite such intensive therapy, cancer recurrence is common, and most tumors become refractory to prior therapy, leaving patients with few conventional treatment options. Natural killer (NK) cells are non-major histocompatibility complex (MHC)-restricted lymphocytes that boast several complex killing mechanisms but at an added advantage of not causing graft-versus-host disease, making use of allogeneic NK cells a potential therapeutic option. On top of their killing capacity, NK cells also produce several cytokines and growth factors that act as key regulators of the adaptive immune system, positioning themselves as ideal effector cells for stimulating heavily pretreated immune systems. Despite this promise, clinical efficacy of adoptive NK cell therapy to date has been inconsistent, prompting a detailed understanding of the biological pathways within NK cells that can be leveraged to develop “next generation” NK cell therapies. Here, we review advances in current approaches to optimizing the NK cell antitumor response including combination with other immunotherapies, cytokines, checkpoint inhibition, and engineering NK cells with chimeric antigen receptors (CARs) for the treatment of pediatric solid tumors.


Cancers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 2 ◽  
Author(s):  
Marisa Market ◽  
Katherine Baxter ◽  
Leonard Angka ◽  
Michael Kennedy ◽  
Rebecca Auer

Natural Killer (NK) cells are granular lymphocytes of the innate immune system that are able to recognize and kill tumor cells without undergoing clonal selection. Discovered over 40 years ago, they have since been recognized to possess both cytotoxic and cytokine-producing effector functions. Following trauma, NK cells are suppressed and their effector functions are impaired. This is especially important for cancer patients undergoing the removal of solid tumors, as surgery has shown to contribute to the development of metastasis and cancer recurrence postoperatively. We have recently shown that NK cells are critical mediators in the formation of metastasis after surgery. While research into the mechanism(s) responsible for NK cell dysfunction is ongoing, knowledge of these mechanisms will pave the way for perioperative therapeutics with the potential to improve cancer outcomes by reversing NK cell dysfunction. This review will discuss mechanisms of suppression in the postoperative environment, including hypercoagulability, suppressive soluble factors, the expansion of suppressive cell populations, and how this affects NK cell biology, including modulation of cell surface receptors, the potential for anergy, and immunosuppressive NK cell functions. This review will also outline potential immunotherapies to reverse postoperative NK dysfunction, with the goal of preventing surgery-induced metastasis.


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