IgG antiplatelet immunity is dependent on an early innate natural killer cell–derived interferon-γ response that is regulated by CD8+ T cells

Blood ◽  
2004 ◽  
Vol 103 (7) ◽  
pp. 2705-2709 ◽  
Author(s):  
Ebrahim Sayeh ◽  
Katherine Sterling ◽  
Edwin Speck ◽  
John Freedman ◽  
John W. Semple

Abstract The mechanisms responsible for immunoglobulin G (IgG) immunity against allogeneic platelets are poorly understood. We studied the role that murine recipient CD8+ T and natural killer (NK) cells play in immunity against allogeneic platelets. BALB/c mice were depleted of the cells by cell-specific antibodies, transfused weekly with platelets from C57BL/6 mice, and serum IgG antidonor antibodies were measured by flow cytometry. While allogeneic platelet transfusions into wild-type recipients stimulated IgG antidonor antibodies in all mice by the fifth transfusion, CD8-depleted mice had significantly (P < .001) enhanced antibody production. Isotype analysis revealed that CD8+ T cells suppressed T-helper 2 (Th2)-associated IgG1 but enhanced Th1-associated IgG2a. Compared with wild-type mice, platelet transfusions into CD8-depleted mice stimulated enhanced intracellular interferon (IFN)-γ production by CD4- lymphocytes within 24 hours after the first transfusion. The early IFN-γ response correlated with nitric oxide-dependent splenic cytotoxicity (P < .001). In asialo ganglioside monosialic acid 1 (GM1)-depleted mice transfused with allogeneic platelets, the IFN-γ production, splenic cytotoxicity, and IgG antidonor antibody response were significantly suppressed. These results demonstrate that IgG antiplatelet immunity is dependent on an early NK cell-derived IFN-γ response that is negatively regulated by CD8+ T cells and suggest that targeting innate NK cell responses may significantly reduce platelet alloimmunization. (Blood. 2004;103:2705-2709)

Blood ◽  
2006 ◽  
Vol 107 (6) ◽  
pp. 2364-2372 ◽  
Author(s):  
Sabrina Chiesa ◽  
Michael Mingueneau ◽  
Nicolas Fuseri ◽  
Bernard Malissen ◽  
David H. Raulet ◽  
...  

AbstractNatural killer (NK) cells express an array of activating receptors that associate with DAP12 (KARAP), CD3ζ, and/or FcRγ ITAM (immunoreceptor tyrosine-based activation motif)–bearing signaling subunits. In T and mast cells, ITAM-dependent signals are integrated by critical scaffolding elements such as LAT (linker for activation of T cells) and NTAL (non–T-cell activation linker). Using mice that are deficient for ITAM-bearing molecules, LAT or NTAL, we show that NK cell cytotoxicity and interferon-γ secretion are initiated by ITAM-dependent and -independent as well as LAT/NTAL-dependent and -independent pathways. The role of these various signaling circuits depends on the target cell as well as on the activation status of the NK cell. The multiplicity and the plasticity of the pathways that initiate NK cell effector functions contrast with the situation in T cells and B cells and provide an explanation for the resiliency of NK cell effector functions to various pharmacologic inhibitors and genetic mutations in signaling molecules.


2007 ◽  
Vol 81 (8) ◽  
pp. 4070-4079 ◽  
Author(s):  
April Keim Parker ◽  
Scott Parker ◽  
Wayne M. Yokoyama ◽  
John A. Corbett ◽  
R. Mark L. Buller

ABSTRACT Natural killer (NK) cells play a pivotal role in the innate immune response to viral infections, particularly murine cytomegalovirus (MCMV) and human herpesviruses. In poxvirus infections, the role of NK cells is less clear. We examined disease progression in C57BL/6 mice after the removal of NK cells by both antibody depletion and genetic means. We found that NK cells were crucial for survival and the early control of virus replication in spleen and to a lesser extent in liver in C57BL/6 mice. Studies of various knockout mice suggested that γδ T cells and NKT cells are not important in the C57BL/6 mousepox model and CD4+ and CD8+ T cells do not exhibit antiviral activity at 6 days postinfection, when the absence of NK cells has a profound effect on virus titers in spleen and liver. NK cell cytotoxicity and/or gamma interferon (IFN-γ) secretion likely mediated the antiviral effect needed to control virus infectivity in target organs. Studies of the effects of ectromelia virus (ECTV) infection on NK cells demonstrated that NK cells proliferate within target tissues (spleen and liver) and become activated following a low-dose footpad infection, although the mechanism of activation appears distinct from the ligand-dependent activation observed with MCMV. NK cell IFN-γ secretion was detected by intracellular cytokine staining transiently at 32 to 72 h postinfection in the lymph node, suggesting a role in establishing a Th1 response. These results confirm a crucial role for NK cells in controlling an ECTV infection.


2015 ◽  
Vol 90 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Georges Abboud ◽  
Vikas Tahiliani ◽  
Pritesh Desai ◽  
Kyle Varkoly ◽  
John Driver ◽  
...  

ABSTRACTIn establishing a respiratory infection, vaccinia virus (VACV) initially replicates in airway epithelial cells before spreading to secondary sites of infection, mainly the draining lymph nodes, spleen, gastrointestinal tract, and reproductive organs. We recently reported that interferon gamma (IFN-γ) produced by CD8 T cells ultimately controls this disseminated infection, but the relative contribution of IFN-γ early in infection is unknown. Investigating the role of innate immune cells, we found that the frequency of natural killer (NK) cells in the lung increased dramatically between days 1 and 4 postinfection with VACV. Lung NK cells displayed an activated cell surface phenotype and were the primary source of IFN-γ prior to the arrival of CD8 T cells. In the presence of an intact CD8 T cell compartment, depletion of NK cells resulted in increased lung viral load at the time of peak disease severity but had no effect on eventual viral clearance, disease symptoms, or survival. In sharp contrast, RAG−/−mice devoid of T cells failed to control VACV and succumbed to infection despite a marked increase in NK cells in the lung. Supporting an innate immune role for NK cell-derived IFN-γ, we found that NK cell-depleted or IFN-γ-depleted RAG−/−mice displayed increased lung VACV titers and dissemination to ovaries and a significantly shorter mean time to death compared to untreated NK cell-competent RAG−/−controls. Together, these findings demonstrate a role for IFN-γ in aspects of both the innate and adaptive immune response to VACV and highlight the importance of NK cells in T cell-independent control of VACV in the respiratory tract.IMPORTANCEHerein, we provide the first systematic evaluation of natural killer (NK) cell function in the lung after infection with vaccinia virus, a member of thePoxviridaefamily. The respiratory tract is an important mucosal site for entry of many human pathogens, including poxviruses, but precisely how our immune system defends the lung against these invaders remains unclear. Natural killer cells are a type of cytotoxic lymphocyte and part of our innate immune system. In recent years, NK cells have received increasing levels of attention following the discovery that different tissues contain specific subsets of NK cells with distinctive phenotypes and function. They are abundant in the lung, but their role in defense against respiratory viruses is poorly understood. What this study demonstrates is that NK cells are recruited, activated, and contribute to protection of the lung during a severe respiratory infection with vaccinia virus.


2007 ◽  
Vol 204 (10) ◽  
pp. 2397-2405 ◽  
Author(s):  
Rossana Trotta ◽  
David Ciarlariello ◽  
Jessica Dal Col ◽  
Jeffrey Allard ◽  
Paolo Neviani ◽  
...  

Monokines (i.e., interleukin [IL]-12, -18, and -15) induce natural killer (NK) cells to produce interferon-γ (IFN-γ), which is a critical factor for immune surveillance of cancer and monocyte clearance of infection. We show that SET, which is a potent inhibitor of protein phosphatase type 2A (PP2A) activity, is highly expressed in human CD56bright NK cells, which produce more IFN-γ than CD56dim NK cells. SET was up-regulated upon monokine stimulation of primary human NK cells. Furthermore, ectopic overexpression of SET significantly enhanced IFN-γ gene expression in monokine-stimulated NK cells. In contrast, RNAi-mediated suppression of SET expression renders NK cells inefficient in producing high levels of IFN-γ in response to monokine costimulation. Mechanistically, suppression of PP2A activity by SET is important for IFN-γ gene expression in NK cells. In fact, treatment of primary human NK cells with the PP2A activator 1,9-dideoxy-forskolin, as well as administration of the drug to C57BL/6 mice, significantly reduced NK-dependent IFN-γ production in response to monokine treatment. Further, SET knockdown or pharmacologic activation of PP2A diminished extracellular signal-regulated kinase 1/2, p65RelA, signal transducer and activator of transduction 4 (STAT4), and STAT5 activity in monokine-stimulated NK cells, potentially contributing to the reduction in IFN-γ gene expression. Thus, SET expression is essential for suppressing PP2A phosphatase activity that would otherwise limit NK cell antitumoral and/or antiinflammatory functions by impairing NK cell production of IFN-γ.


Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Sarah J Fitzgerald ◽  
James Hogg ◽  
Evangeline Deer ◽  
Nathan Campbell ◽  
Owen Herrock ◽  
...  

Preeclampsia (PE) is characterized by new onset hypertension (HTN), intrauterine growth restriction (IUGR), multi-organ dysfunction, and is associated with increased inflammatory cytokines, such as interleukin 17 (IL-17). More recent studies demonstrate a role for mitochondrial (mt) dysfunction/mtROS in the pathogenesis of PE. Although we have shown T helper cells from a rat model of PE cause HTN and mt dysfunction the causative factors for mt dysfunction are still being identified. In addition, we have shown that IL-17 cause HTN, IUGR and activate natural killer (NK) cells, and cause mt dysfunction in pregnant Sprague Dawley rats. However, in our previous studies we couldn’t differentiate the effect of activated TH cells versus IL-17 to cause these characteristics of PE. The athymic nude rat model lacks mature T cells but does have other components of the immune system, and will thus allow us to examine the role of IL-17 in the absence of TH cells in the pathophysiology of PE. We hypothesize that in the absence of T cells IL-17 induces HTN, NK cell activation and IUGR which is associated with renal and placental mt dysfunction during pregnancy. To test our hypothesis, IL-17 (150 pg/day) was infused via osmotic minipumps inserted on gestation day (GD) 14. Blood pressure (MAP) and mt function were measured on GD19 and were compared to untreated pregnant (NP) athymic nude rats. In response to IL-17; MAP increased from 95±4mmHg in NP(n=6) to 115±2 in NP+IL-17(n=6) (p<0.001); pup weight decreased from 1.46±0.2 g in NP (n=6) to 0.98±0.07g in NP+IL-17 (n=6) (p<0.05); NK cell activation increased from 0±0 %lymphocytes in NP (n=3) to 0.4±0.1% lymphocytes in NP+IL-17 rats (n=6). Interestingly, placental mtROS reduced 54% fold compared to NP and renal mtROS reduced 51.2% compared to NP. ATP production increased from 15.53±1.6 pmol of O2/sec/mg in NP (n=3) to 105.5±91 pmol of O2/sec/mg in NP+IL-17 (n=3) in the placenta, and from 1196±460 pmol of O2/sec/mg in NP (n=4) to 2016±951 pmol of O2/sec/mg NP+IL17 (n=4) in the kidney. These results show that although IL-17 induces HTN, IUGR, and NK cell activation independent of T cells, T cells are necessary for reduced mitochondrial function observed in PE and in rat models of placental ischemia.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Hee Young Na ◽  
Yujun Park ◽  
Soo Kyung Nam ◽  
Jiwon Koh ◽  
Yoonjin Kwak ◽  
...  

Abstract Background Natural killer (NK) cells mediate the anti-tumoral immune response as an important component of innate immunity. The aim of this study was to investigate the prognostic significance and functional implication of NK cell-associated surface receptors in gastric cancer (GC) by using multiplex immunohistochemistry (mIHC). Methods We performed an mIHC on tissue microarray slides, including 55 GC tissue samples. A total of 11 antibodies including CD57, NKG2A, CD16, HLA-E, CD3, CD20, CD45, CD68, CK, SMA, and ki-67 were used. CD45 + CD3-CD57 + cells were considered as CD57 + NK cells. Results Among CD45 + immune cells, the proportion of CD57 + NK cell was the lowest (3.8%), whereas that of CD57 + and CD57- T cells (65.5%) was the highest, followed by macrophages (25.4%), and B cells (5.3%). CD57 + NK cells constituted 20% of CD45 + CD57 + immune cells while the remaining 80% were CD57 + T cells. The expression of HLA-E in tumor cells correlated with that in tumoral T cells, B cells, and macrophages, but not CD57 + NK cells. The higher density of tumoral CD57 + NK cells and tumoral CD57 + NKG2A + NK cells was associated with inferior survival. Conclusions Although the number of CD57 + NK cells was lower than that of other immune cells, CD57 + NK cells and CD57 + NKG2A + NK cells were significantly associated with poor outcomes, suggesting that NK cell subsets play a critical role in GC progression. NK cells and their inhibitory receptor, NKG2A, may be potential targets in GC.


2019 ◽  
Vol 116 (35) ◽  
pp. 17460-17469 ◽  
Author(s):  
Leah Schmidt ◽  
Banu Eskiocak ◽  
Ryan Kohn ◽  
Celeste Dang ◽  
Nikhil S. Joshi ◽  
...  

Natural killer (NK) cells inhibit tumor development in mouse models and their presence in tumors correlates with patient survival. However, tumor-associated NK cells become dysfunctional; thus, stimulation of NK cells in cancer is emerging as an attractive immunotherapeutic strategy. In a mouse model of lung adenocarcinoma, NK cells localized to tumor stroma with immature phenotypes and low functional capacity. To test their responsiveness within established disease, we engineered a system for inducible expression of activating ligands in tumors. After stimulation, NK cells localized inside tumors, with increased cytokine production capacity. Strikingly, T cells were also recruited to tumors in an NK cell-dependent manner, and exhibited higher functionality. In neoantigen-expressing tumors, NK cell stimulation enhanced the number and function of tumor-specific T cells and, in long-term settings, reduced tumor growth. Thus, even in established disease NK cells can be activated to contribute to antitumor immunity, supporting their potential as an important target in cancer immunotherapy.


Blood ◽  
2005 ◽  
Vol 106 (6) ◽  
pp. 2076-2082 ◽  
Author(s):  
Anja Fuchs ◽  
Marina Cella ◽  
Takayuki Kondo ◽  
Marco Colonna

Abstract Natural killer (NK) cell-mediated cytotoxicity is triggered by multiple activating receptors associated with the signaling adaptor protein DNAX activation protein 12/killer cell-activating receptor-associated protein (DAP12/KARAP). Here, we show that one of these receptors, NKp44, is present on a subset of natural interferon-producing cells (IPCs) in tonsils. NKp44 expression can also be induced on blood IPCs after in vitro culture with interleukin 3 (IL-3). Crosslinking of NKp44 does not trigger IPC-mediated cytotoxicity but, paradoxically, inhibits interferon α (IFN-α) production by IPCs in response to cytosine-phosphate-guanosine (CpG) oligonucleotides. We find that IPCs in tonsils are in close contact with CD8+ T cells and demonstrate that a subset of memory CD8+ T cells produces IL-3. Therefore, IL-3-mediated induction of NKp44 on IPCs may be an important component of the ongoing crosstalk between the innate and adaptive immune response that allows memory CD8+ T cells to control the IPC response to virus. (Blood. 2005;106: 2076-2082)


2005 ◽  
Vol 79 (21) ◽  
pp. 13509-13518 ◽  
Author(s):  
Jürgen Hausmann ◽  
Axel Pagenstecher ◽  
Karen Baur ◽  
Kirsten Richter ◽  
Hanns-Joachim Rziha ◽  
...  

ABSTRACT Borna disease virus (BDV) frequently causes meningoencephalitis and fatal neurological disease in young but not old mice of strain MRL. Disease does not result from the virus-induced destruction of infected neurons. Rather, it is mediated by H-2 k -restricted antiviral CD8 T cells that recognize a peptide derived from the BDV nucleoprotein N. Persistent BDV infection in mice is not spontaneously cleared. We report here that N-specific vaccination can protect wild-type MRL mice but not mutant MRL mice lacking gamma interferon (IFN-γ) from persistent infection with BDV. Furthermore, we observed a significant degree of resistance of old MRL mice to persistent BDV infection that depended on the presence of CD8 T cells. We found that virus initially infected hippocampal neurons around 2 weeks after intracerebral infection but was eventually cleared in most wild-type MRL mice. Unexpectedly, young as well as old IFN-γ-deficient MRL mice were completely susceptible to infection with BDV. Moreover, neurons in the CA1 region of the hippocampus were severely damaged in most diseased IFN-γ-deficient mice but not in wild-type mice. Furthermore, large numbers of eosinophils were present in the inflamed brains of IFN-γ-deficient mice but not in those of wild-type mice, presumably because of increased intracerebral synthesis of interleukin-13 and the chemokines CCL1 and CCL11, which can attract eosinophils. These results demonstrate that IFN-γ plays a central role in host resistance against infection of the central nervous system with BDV and in clearance of BDV from neurons. They further indicate that IFN-γ may function as a neuroprotective factor that can limit the loss of neurons in the course of antiviral immune responses in the brain.


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