Latent Murine Herpesvirus-4 Infection Arms NK Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3678-3678
Author(s):  
Douglas W White ◽  
Catherine R Keppel ◽  
Stephanie E Schneider ◽  
James Coder ◽  
Tiffany A Reese ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Function ◽  
Nk Cell ◽  
Granzyme B ◽  
Acute Infection ◽  
Herpesvirus Infection ◽  
Healthy Humans ◽  
Latently Infected ◽  
Herpesvirus 4

Abstract Abstract 3678 Poster Board III-614 Natural killer (NK) cells are lymphocytes originally identified by their ability to kill target cells without prior sensitization. However, murine NK cells require an antecedent ‘arming’ event to translate cytotoxic effector proteins (perforin and granzymes) resulting in potent cytotoxic capacity. In contrast to mice, most NK cells (CD56dim) from the peripheral blood of healthy humans are armed with pre-formed perforin and granzyme B proteins and mediate killing of NK sensitive targets directly ex vivo. This suggests that NK cells from specific pathogen free (SPF) laboratory mice are lacking a critical arming event present in healthy humans, and provides an experimental system to elucidate the events that result in NK cell arming in vivo. Since latent herpesviruses are highly prevalent and alter multiple aspects of host immunity, we hypothesized that the immune environment created by a latent herpesvirus infection arms NK cells. NK cells from mice latently infected with Murid herpesvirus 4 (MuHV-4), a virus closely related to the human viruses Kaposi's sarcoma associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), were armed as evidenced by increased granzyme B protein expression, cytotoxicity, and interferon-gamma production. Adoptive transfer experiments with naïve NK cells indicated that NK arming occurred rapidly (≤ 72 hours) in the latently infected host and did not require acute infection. In addition, experiments utilizing a genetic variant of MuHV-4 that acutely infects mice similar to wild-type MuHV-4, but does not establish latency, confirmed that acute infection was not responsible for this NK cell modulation. Finally, NK cells armed by latent infection protected the host against a lethal RMA-S lymphoma challenge. Thus, the immune environment created by a latent herpesvirus infection arms NK cell function in vivo. These results indicate that some of the differences between human and SPF laboratory-mouse NK cell function may reflect a disparity in immune activation induced by chronic virus infection, as opposed to an intrinsic difference in the NK cells themselves. Moreover, these findings indicate that the activation state of the innate immune system needs to be taken into account when using mice to model immune responses against pathogens and tumors. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Latent herpesvirus infection arms NK cells

Blood ◽  
2010 ◽  
Vol 115 (22) ◽  
pp. 4377-4383 ◽  
Author(s):  
Douglas W. White ◽  
Catherine R. Keppel ◽  
Stephanie E. Schneider ◽  
Tiffany A. Reese ◽  
James Coder ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Function ◽  
Nk Cell ◽  
Interferon Γ ◽  
Target Cells ◽  
Herpesvirus Infection ◽  
Acute Viral Infection ◽  
Latently Infected ◽  
Herpesvirus 4

AbstractNatural killer (NK) cells were identified by their ability to kill target cells without previous sensitization. However, without an antecedent “arming” event, NK cells can recognize, but are not equipped to kill, target cells. How NK cells become armed in vivo in healthy hosts is unclear. Because latent herpesviruses are highly prevalent and alter multiple aspects of host immunity, we hypothesized that latent herpesvirus infection would arm NK cells. Here we show that NK cells from mice latently infected with Murid herpesvirus 4 (MuHV-4) were armed as evidenced by increased granzyme B protein expression, cytotoxicity, and interferon-γ production. NK-cell arming occurred rapidly in the latently infected host and did not require acute viral infection. Furthermore, NK cells armed by latent infection protected the host against a lethal lymphoma challenge. Thus, the immune environment created by latent herpesvirus infection provides a mechanism whereby host NK-cell function is enhanced in vivo.

Granzyme B Is Important for Treg-Mediated Suppression of NK-Dependent Tumor Clearance In Vivo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 133-133
Author(s):  
Xuefang Cao ◽  
Sheng F. Cai ◽  
Todd A. Fehniger ◽  
Jiling Song ◽  
David Piwnica-Worms ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Function ◽  
Nk Cell ◽  
Granzyme B ◽  
Tumor Burden ◽  
Tumor Challenge ◽  
Granzyme A ◽  
Tumor Environment ◽  
Deficient Mice

Abstract NK-dependent clearance of RMAS lymphoma and B16 melanoma (MHC Ilow) has been demonstrated in NK cell-deficient mice (Kim S et al, PNAS. 2000 Mar; 97(6): 2731–6). We recently investigated the roles of granzyme (Gzm) A and B in NK-dependent clearance of RMAS and B16 cells. The survival curves following intravenous injection of 2x105 RMAS cells are shown in the Figure; similar results were found with B16 cells. All granzyme AxB-deficient mice died within 6 weeks. Survival of granzyme A-deficient mice was similar to that of WT mice. Surprisingly, granzyme B-deficient mice were more resistant than WT mice to these tumor challenges. Previously, our laboratory demonstrated that human regulatory T (Treg) cells can use the granule exocytosis pathway to kill a variety of autologous immune cells in vitro (Grossman WJ et al, Immunity. 2004 Oct; 21(4): 589–601). Based on these results, we hypothesized that these tumor cell lines may induce granzyme B expression in Tregs, which in turn suppress the function of the NK cells responsible for clearing the tumors. Indeed, flow cytometric studies revealed that granzyme B (but not granzyme A) was highly expressed in 10–30% of CD4+/FoxP3+ Tregs found in the tumor environment (i.e. ascites fluid, tumor-infiltrated livers, or lungs). In contrast, very few granzyme B-expressing cells (<1%) were detected in the Tregs found in the peripheral spleens or lymph nodes of tumor-bearing mice or in the spleens, livers and lungs of naive mice. Within the NK cell compartment, granzyme A expression was constitutive, and it was persistently expressed following tumor challenge. While granzyme B was detected in only 1–5% of NK cells in the spleens, livers and lungs of naive mice, 20–40% of NK cells in the tumor environment expressed granzyme B following tumor challenge. To determine whether Tregs require granzyme B to suppress NK cell function in vivo, we purified Tregs (95% pure CD4+/CD25+ cells) from the resting spleens of both WT and granzyme B-deficient mice, and co-injected them intraperitoneally with 2x106 luciferase-tagged RMAS cells into granzyme B-deficient mice. Tumor burden was assessed using in vivo bioluminescence imaging. Add-back of 2x106 WT Tregs into granzyme B-deficient mice restored tumor growth to 40% of that observed at day 7 in WT mice, whose tumor burden was approximately 50-fold higher than that of granzyme B-deficient mice. Add-back of equal doses of granzyme B-deficient Tregs had no effect on tumor burden. Our data suggest that these tumor cell lines induce the expression of granzyme B in Tregs, which subsequently suppress tumor-specific NK cells. These data demonstrate for the first time that granzyme B plays a crucial role in Treg-mediated suppression of NK cell function in vivo. By recruiting and activating Tregs that inhibit NK cell function, these tumors gain a survival advantage that is lost in the setting of granzyme B deficiency in the Tregs. This study therefore suggests that targeted inhibition of granzyme B in Tregs may represent a novel approach to break Treg-mediated tumor tolerance. Figure Figure

Contribution of Natural Killer Cells to Inhibition of Angiogenesis by Interleukin-12

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1612-1621 ◽  
Author(s):  
Lei Yao ◽  
Cecilia Sgadari ◽  
Keizo Furuke ◽  
Eda T. Bloom ◽  
Julie Teruya-Feldstein ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Function ◽  
Nk Cell ◽  
Primary Cultures ◽  
Interleukin 12 ◽  
Ifn Γ

Abstract Interleukin-12 (IL-12) inhibits angiogenesis in vivo by inducing interferon-γ (IFN-γ) and other downstream mediators. Here, we report that neutralization of natural killer (NK) cell function with antibodies to either asialo GM1 or NK 1.1 reversed IL-12 inhibition of basic fibroblast growth factor (bFGF)-induced angiogenesis in athymic mice. By immunohistochemistry, those sites where bFGF-induced neovascularization was inhibited by IL-12 displayed accumulation of NK cells and the presence of IP-10–positive cells. Based on expression of the cytolytic mediators perforin and granzyme B, the NK cells were locally activated. Experimental Burkitt lymphomas treated locally with IL-12 displayed tumor tissue necrosis, vascular damage, and NK-cell infiltration surrounding small vessels. After activation in vitro with IL-12, NK cells from nude mice became strongly cytotoxic for primary cultures of syngeneic aortic endothelial cells. Cytotoxicity was neutralized by antibodies to IFN-γ. These results document that NK cells are required mediators of angiogenesis inhibition by IL-12, and provide evidence that NK-cell cytotoxicity of endothelial cells is a potential mechanism by which IL-12 can suppress neovascularization.

scholarly journals KIR reconstitution is altered by T cells in the graft and correlates with clinical outcomes after unrelated donor transplantation

Blood ◽  
2005 ◽  
Vol 106 (13) ◽  
pp. 4370-4376 ◽  
Author(s):  
Sarah Cooley ◽  
Valarie McCullar ◽  
Rosanna Wangen ◽  
Tracy L. Bergemann ◽  
Stephen Spellman ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Clinical Outcomes ◽  
Hematopoietic Cell Transplantation ◽  
Cell Function ◽  
Nk Cell ◽  
Interferon Γ ◽  
Unrelated Donor ◽  
Ifn Γ

Although unrelated hematopoietic cell transplantation (HCT) is curative for many hematologic malignancies, complications and relapse remain challenging obstacles. Natural killer (NK) cells, which recover quickly after transplantation, produce cytokines and express killer immunoglobulin-like receptors (KIRs) that regulate their cytotoxicity. Some clinical trials based on a KIR ligand mismatch strategy are associated with less relapse and increased survival, but results are mixed. We hypothesized that T cells in the graft may affect NK cell function and KIR expression after unrelated transplantation and that these differences correlate with clinical outcomes. NK cell function was evaluated using 77 paired samples from the National Marrow Donor Program Research Repository. Recipient NK cells at 100 days after both unmanipulated bone marrow (UBM) and T-cell depleted (TCD) transplants were compared with NK cells from their healthy donors. NK cells expressed fewer KIRs and produced more interferon γ (IFN-γ) after UBM compared to TCD transplants. Multivariate models showed that increased NK cell IFN-γ production correlated with more acute graft-versus-host disease (GVHD), and decreased KIR expression correlated with inferior survival. These results support the notion that T cells in the graft affect NK cell reconstitution in vivo. Understanding these mechanisms may result in strategies to improve clinical outcomes from unrelated HCT.

Genetically Reengineered K562 Cells Significantly Expand Cord Blood (CB) Natural Killer (NK) Cells Ex-Vivo Expanded with Increased NK Cell Activation and Cytolytic Activity Both In-Vitro and In-Vivo: Potential Use In Adoptive Cellular Immunotherapy (ACI)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3928-3928
Author(s):  
Michele Levin ◽  
Janet Ayello ◽  
Frances Zhao ◽  
Andrew Stier ◽  
Lauren Tiffen ◽  
...  
Keyword(s):  
Nk Cells ◽  
Nk Cell ◽  
Ex Vivo ◽  
Granzyme B ◽  
K562 Cells ◽  
Cytolytic Activity ◽  
Scid Mice ◽  
Activation Marker

Abstract Abstract 3928 Background: NK cells play a role in reducing relapse in hematological malignancy following AlloSCT (Dunbar et al, Haematologica, 2008). NK cell limitations include lack of tumor recognition and/or limited numbers of viable and functional NK cells (Shereck/Cairo et al, Ped Bld Can, 2007). NK ACI provide safe and effective therapy against tumor relapse; yet NK cells are limited to specific cancer types and not all patients demonstrate optimal response (Ruggieri et al. Science, 2002; Ljunggren et al. Nat Rev Immuno, 2007). To circumvent these limitations, methods to expand and activate PBMNCs with genetically engineered K562 cells expressing membrane bound IL-15 and 41BB ligand (K562-mbIL15-41BBL [modK562]; Imai/Campana et al, Blood, 2005) have shown to significantly increase NK cells in number and maintain heterogeneous KIR expression (Fusaki/Campana et al BJH, 2009). We have shown that CB NK cells can be activated/expanded and exhibit enhanced cytolytic activity when cultured in a cytokines/antibody cocktail (Ayello/Cairo et al, BBMT, 2006; Exp Heme, 2009). Objective: To evaluate CBNK expansion, activation, cytolytic mechanism and function against Burkitt lymphoma (BL) tumor target and its influence on NK cell mediated in-vitro and in-vivo cytotoxicity in NOD-SCID mice following stimulation with modK562 cells (generously supplied by D.Campana, St Jude's Children's Hospital, Memphis, Tx). Methods: Following 100GY irradiation, modK562cells were incubated 1:1 with CBMNCs in RPMI+IL-2 (10IU/ml) for 7 days in 5%CO2, 37°C. NK activation marker (LAMP-1), perforin and granzyme B were determined by flow cytometry. Cytotoxicty was determined via europium assay at 20:1 E:T ratio with Ramos (BL) tumor targets (ATCC). The mammalian expression construct (ffLucZeo-pcDNA (generously supplied by L.Cooper, MD, PhD) was transfected to BL cells using lipofectin and selected by zeocin for stable transfection. Six week old NOD-SCID mice received 5×106 BL cells subcutaneously. Upon engraftment, xenografted NOD-SCID mice were divided in 5 groups: injected with PBS (control), BL only, 5×106 wildtype (WT) K562 expanded (E) CBNK cells, modK562 expanded (E) CB NK cells (5×106) and modK562 expanded (E) CBNK cells (5×107). Ex-vivo ECBNK cells were injected weekly for 5 weeks and xenografted NOD-SCID mice were monitored by volumetric measurement of tumor size (Tomayko/Reynolds, Can Chemother Pharmac, 1989), bioluminescent imaging (Inoue et al Exp Heme, 2007) and survival. The survival distribution for each group was estimated using the Fisher exact test. Results: On Day 0, NK cells (CD56+/3-) population was 3.9±1.3%. After 7 days, modK562 expanded CBNK cells was significantly increased compared to WTK562 and media alone (72±3.9 vs 43±5.9 vs 9±2.4%, p<0.01). This represented a 35-fold or 3374±385% increase of the input NK cell number. This was significantly increased compared to WTK562 (1771±300%, p<0.05). ModK562 ECBNK cells demonstrated increased perforin and granzyme B expression compared to WTK562 (42±1.5 vs 15±0.5%,p<0.001; 22±0.5 vs 11±0.3%,p<0.001, respectively). Cytotoxicity was against BL tumor targets was significantly increased (42±3 vs 18±2%,p<0.01), along with NK activation marker expression, CD107a (p<0.05). At 5 weeks, in-vivo studies demonstrated increased survival of NOD-SCID mice receiving both 5×106 and 5×107 modK562 ECBNK cells when compared to those with no treatment (p=0.05, p=0.0007, respectively). There was no difference in survival when comparing mice that received 5×106 vs 5×107 modK562 ECBNK cells (p=0.0894) at 5 weeks. Tumor volume of mice receiving either dose of modK562 ECBNK cells was significantly less than those receiving WTK562 ECBNK cells (1.92±0.57 and 0.37±0.05 vs 3.41±0.25, p=0.0096 and p=0.0001, respectively). Conclusions: CBMNCs stimulated and expanded with modK562 cells results in significant expansion of CBNK cells with enhanced in-vitro cytotoxicity, significant receptor expression of NK activation marker (LAMP-1), and perforin and granzyme B. Furthermore, modK562 ECBNK cells leads to increased survival and lower tumor burden of NOD-SCID mice xenografted with BL. Future directions include modK562 ECBNK cells to be genetically modified to express chimeric antigen receptor CD20 (MSCV-antiCD20-41BB-CD3 ζ) against CD20+ hematologic malignancies for future studies to evaluate whether targeting enhances in-vitro and in-vivo cytotoxicity. Disclosures: No relevant conflicts of interest to declare.

A family with Papillon-Lefèvre syndrome reveals a requirement for cathepsin C in granzyme B activation and NK cell cytolytic activity

Blood ◽  
2006 ◽  
Vol 107 (9) ◽  
pp. 3665-3668 ◽  
Author(s):  
Josephine L. Meade ◽  
Erika A. de Wynter ◽  
Peter Brett ◽  
Saghira Malik Sharif ◽  
C. Geoffrey Woods ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Function ◽  
Nk Cell ◽  
Granzyme B ◽  
Interleukin 2 ◽  
Target Cells ◽  
Loss Of Function ◽  
Cathepsin C ◽  
Cytolytic Function

Activation of granzyme B, a key cytolytic effector molecule of natural killer (NK) cells, requires removal of an N-terminal pro-domain. In mice, cathepsin C is required for granzyme processing and normal NK cell cytolytic function, whereas in patients with Papillon-Lefèvre syndrome (PLS), loss-of-function mutations in cathepsin C do not affect lymphokine activated killer (LAK) cell function. Here we demonstrate that resting PLS NK cells do have a cytolytic defect and fail to induce the caspase cascade in target cells. NK cells from these patients contain inactive granzyme B, indicating that cathepsin C is required for granzyme B activation in unstimulated human NK cells. However, in vitro activation of PLS NK cells with interleukin-2 restores cytolytic function and granzyme B activity by a cathepsin C-independent mechanism. This is the first documented example of a human mutation affecting granzyme B activity and highlights the importance of cathepsin C in human NK cell function.

scholarly journals Mononuclear myeloid-derived “suppressor” cells express RAE-1 and activate natural killer cells

Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 4080-4089 ◽  
Author(s):  
Norman Nausch ◽  
Ioanna E. Galani ◽  
Eva Schlecker ◽  
Adelheid Cerwenka
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Function ◽  
Nk Cell ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Tumor Bearing

Abstract Myeloid-derived suppressor cells (MDSCs) accumulate in cancer patients and tumor-bearing mice and potently suppress T-cell activation. In this study, we investigated whether MDSCs regu-late natural killer (NK)–cell function. We discovered that mononuclear Gr-1+CD11b+F4/80+ MDSCs isolated from RMA-S tumor-bearing mice do not suppress, but activate NK cells to produce high amounts of IFN-γ. Gr-1+CD11b+F4/80+ MDSCs isolated from tumor-bearing mice, but not myeloid cells from naive mice, expressed the ligand for the activating receptor NKG2D, RAE-1. NK-cell activation by MDSCs depended partially on the interaction of NKG2D on NK cells with RAE-1 on MDSCs. NK cells eliminated Gr-1+CD11b+F4/80+ MDSCs in vitro and upon adoptive transfer in vivo. Finally, depletion of Gr-1+ cells that comprise MDSCs confirmed their protective role against the NK-sensitive RMA-S lymphoma in vivo. Our study reveals that MDSCs do not suppress all aspects of antitumor immune responses and defines a novel, unexpected activating role of MDSCs on NK cells. Thus, our results have great impact on the design of immune therapies against cancer aiming at the manipulation of MDSCs.

scholarly journals Proliferation of Highly Cytotoxic Human Natural Killer Cells by OX40L Armed NK-92 With Secretory Neoleukin-2/15 for Cancer Immunotherapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Meng Guo ◽  
Chen Sun ◽  
Yuping Qian ◽  
Liye Zhu ◽  
Na Ta ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Expansion ◽  
Large Scale ◽  
Cell Function ◽  
Treatment Effectiveness ◽  
Nk Cell ◽  
Expansion Mechanism ◽  
Human Natural Killer Cells

Adoptive natural killer (NK) cell transfer has been demonstrated to be a promising immunotherapy approach against malignancies, but requires the administration of sufficient activated cells for treatment effectiveness. However, the paucity of clinical-grade to support the for large-scale cell expansion limits its feasibility. Here we developed a feeder-based NK cell expansion approach that utilizes OX40L armed NK-92 cell with secreting neoleukin-2/15 (Neo-2/15), a hyper-stable mimetic with a high affinity to IL-2Rβγ. The novel feeder cells (NK92-Neo2/15-OX40L) induced the expansion of NK cells with a 2180-fold expansion (median; 5 donors; range, 1767 to 2719) after 21 days of co-culture without added cytokines. These cells were highly cytotoxic against Raji cells and against several solid tumors in vivo. Mechanistically, NK92-Neo2/15-OX40L induced OX40 and OX40L expression on expanded NK cells and promoted the OX40-OX40L positive feedback loop, thus boosting NK cell function. Our data provided a novel NK cell expansion mechanism and insights into OX40-OX40L axis regulation of NK cell expansion.

scholarly journals TIGIT Expression Positively Associates with NK Cell Function in AML Patients

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5250-5250 ◽  
Author(s):  
Bei Jia ◽  
Chenchen Zhao ◽  
David F. Claxton ◽  
W. Christopher Ehmann ◽  
Witold B. Rybka ◽  
...  
Keyword(s):  
Nk Cells ◽  
Therapeutic Strategy ◽  
Cell Function ◽  
Nk Cell ◽  
Granzyme B ◽  
Healthy Controls ◽  
Functional Studies ◽  
Activating Receptors ◽  
Tnf Α ◽  
Ifn Γ

Abstract Natural killer (NK) cells are essential innate immune effectors with promising anti-leukemia activity in acute myeloid leukemia (AML). However, clinical success of applying NK cells in AML treatment has not been achieved. A better understanding of the regulatory mechanisms for NK cell function is important to optimize this therapeutic strategy. T cell immunoglobulin and ITIM domain (TIGIT) is a recently identified inhibitory receptor expressed on T cells and NK cells. Multiple studies including ours have demonstrated its suppressive effect in anti-tumor CD8 T cell response. However whether and how TIGIT impacts NK cells in AML is unknown. Here we performed phenotypic and functional studies on NK cells derived from patients with newly diagnosed AML (n=30). Cells collected from healthy individuals (n=18) were used as controls. TIGIT expression and their contributions to NK cell function in AML were assessed. Peripheral blood samples were first examined by flow cytometry for the frequency of NK cells (defined as CD56+CD3-). The percentage of NK cells among peripheral blood mononuclear cells (PBMCs) in AML patients is comparable with that of healthy controls. In contrast, when we performed functional analysis to assess NK cells for cytokine release upon in vitro stimulation with a human leukemia cell line K562, we observed significantly lower intracellular production of IFN-γ in cells from AML patients compared with that of healthy controls. Consistently NK cells from AML patients expressed less Perforin, indicating a compromised killing capacity. We next evaluated the expression of TIGIT on CD56+CD3- NK cells. As some AML blasts and monocytes also express CD56, we performed multichannel flow cytometry and carefully gated out other cell components when assessing TIGIT expression. To our surprise, we observed a significantly lower frequency of TIGIT-expressing NK cells in AML compared with that of healthy controls (36.82 ±4.543% vs. 48.9±3.818%, P=0.0463). This data indicated that low-TIGIT expression associates with impaired NK cell function and AML progression. We further examined the phenotype and functional status of TIGIT+ NK cells. Expression of activating receptors (CD16 and CD160) and inhibiting receptors (KIR and NKG2A) on TIGIT+ vs. TIGIT- NK cells were analyzed. We observed a significant higher expression of CD16 (51.27±9.009% vs. 20.63±5.334%, P=0.0001) and CD160 (39.84±6.447% vs. 21.24±4.287%, P=0.0103) on TIGIT+ NK cells compared with that of TIGIT- NK cells. By contrast, TIGIT+ NK cells expressed lower KIR (24.06±3.796% vs. 43.59±6.96%, P=0.0046) and NKG2A (7.658±1.717% vs. 18.68±4.256%, P=0.0167) than TIGIT- NK cells. Importantly, functional studies demonstrated an elevated expression of Granzyme B and increased cytokine (IFN-γ and TNF-α) production by TIGIT+ NK cells compared with TIGIT- NK cells (IFN-γ, P=0.0283; TNF-α P=0.0347; Granzyme B, P=0.0493). These data suggest that TIGIT expression on NK cells associated with activated and high functional status. Collectively, our study demonstrates that 1) in line with lower capacity to produce IFN-γ, NK cells from AML patients express less frequency of TIGIT compared with healthy individuals; 2) TIGIT+ NK cells from AML patients express high levels of activating receptors and are highly functional manifested by more cytokine production and enhanced expression of Granzyme B compared with TIGIT- NK cells. These results indicate that in AML patient, TIGIT may contribute to the upregulation of NK cell function. This is in contrast to the observations of CD8 T cells in which TIGIT plays a suppressive role. Targeting TIGIT for cancer treatment is currently under active development. Our findings bring a call for caution on the TIGIT-targeted therapeutic strategy in AML as TIGIT might be a double-edged sword in anti-leukemia immune regulation. Disclosures No relevant conflicts of interest to declare.

scholarly journals NF-kB c-Rel is dispensable for the development but is required for the cytotoxic function of NK cells

2021 ◽  
Author(s):  
Y Vicioso ◽  
K Zhang ◽  
Parameswaran Ramakrishnan ◽  
Reshmi Parameswaran
Keyword(s):  
Nk Cells ◽  
Nk Cell ◽  
Granzyme B ◽  
Conditional Knockout ◽  
Cytotoxic Lymphocytes ◽  
And Control ◽  
Cytotoxic Function

AbstractNatural Killer (NK) cells are cytotoxic lymphocytes critical to the innate immune system. We found that germline deficiency of NF-kB c-Rel results in a marked decrease in cytotoxic function of NK cells, both in vitro and in vivo, with no significant differences in the stages of NK cell development. We found that c-Rel binds to the promoters of perforin and granzyme B, two key proteins required for NK cytotoxicity, and controls their transactivation. We generated a NK cell specific c-Rel conditional knockout to study NK cell intrinsic role of c-Rel and found that both global and conditional c-Rel deficiency leads to decreased perforin and granzyme B expression and thereby cytotoxic function. We also confirmed the role of c-Rel in perforin and granzyme B expression in human NK cells. c-Rel reconstitution rescued perforin and granzyme B expressions in c-Rel deficient NK cells and restored their cytotoxic function. Our results show a previously unknown role of c-Rel in transcriptional regulation of perforin and granzyme B expressions and control of NK cell cytotoxic function.

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