scholarly journals Distinct MHC class I–dependent NK cell–activating receptors control cytomegalovirus infection in different mouse strains

2011 ◽  
Vol 208 (5) ◽  
pp. 1105-1117 ◽  
Author(s):  
Michał Pyzik ◽  
Benoit Charbonneau ◽  
Eve-Marie Gendron-Pontbriand ◽  
Marina Babić ◽  
Astrid Krmpotić ◽  
...  

Recognition of mouse cytomegalovirus (MCMV)–infected cells by activating NK cell receptors was first described in the context of Ly49H, which confers resistance to C57BL/6 mice. We investigated the ability of other activating Ly49 receptors to recognize MCMV-infected cells in mice from various H-2 backgrounds. We observed that Ly49P1 from NOD/Ltj mice, Ly49L from BALB mice, and Ly49D2 from PWK/Pas mice respond to MCMV-infected cells in the context of H-2Dk and the viral protein m04/gp34. Recognition was also seen in the H-2d and/or H-2f contexts, depending on the Ly49 receptor examined, but never in H-2b. Furthermore, BALB.K (H-2k) mice showed reduced viral loads compared with their H-2d or H-2b congenic partners, a reduction which was dependent on interferon γ secretion by Ly49L+ NK cells early after infection. Adoptive transfer of Ly49L+, but not Ly49L−, NK cells significantly increased resistance against MCMV infection in neonate BALB.K mice. These results suggest that multiple activating Ly49 receptors participate in H-2–dependent recognition of MCMV infection, providing a common mechanism of NK cell–mediated resistance against viral infection.

2009 ◽  
Vol 206 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Agnieszka Kielczewska ◽  
Michal Pyzik ◽  
Tianhe Sun ◽  
Astrid Krmpotic ◽  
Melissa B. Lodoen ◽  
...  

Natural killer (NK) cells are crucial in resistance to certain viral infections, but the mechanisms used to recognize infected cells remain largely unknown. Here, we show that the activating Ly49P receptor recognizes cells infected with mouse cytomegalovirus (MCMV) by a process that requires the presence of H2-Dk and the MCMV m04 protein. Using H2 chimeras between H2-Db and -Dk, we demonstrate that the H2-Dk peptide-binding platform is required for Ly49P recognition. We identified m04 as a viral component necessary for recognition using a panel of MCMV-deletion mutant viruses and complementation of m04-deletion mutant (Δm04) virus infection. MA/My mice, which express Ly49P and H2-Dk, are resistant to MCMV; however, infection with Δm04 MCMV abrogates resistance. Depletion of NK cells in MA/My mice abrogates their resistance to wild-type MCMV infection, but does not significantly affect viral titers in mice infected with Δm04 virus, implicating NK cells in host protection through m04-dependent recognition. These findings reveal a novel mechanism of major histocompatability complex class I–restricted recognition of virally infected cells by an activating NK cell receptor.


2008 ◽  
Vol 205 (8) ◽  
pp. 1819-1828 ◽  
Author(s):  
Joseph C. Sun ◽  
Lewis L. Lanier

During development, T and B cells encountering their cognate ligands via antigen-specific receptors are deleted or rendered anergic. Like T and B cells, natural killer (NK) cells express certain receptors, such as Ly49H, associated with immunoreceptor tyrosine-based activation motif–bearing adaptor proteins that transmit activating signals through Syk family kinases. Ly49H binds with high affinity to a mouse cytomegalovirus (MCMV)–encoded glycoprotein, m157, but does not recognize self-antigens. For comparison with the behavior of immature T and B cells exposed to foreign antigens, we addressed the fate of Ly49H+ NK cells that encountered their viral ligand during development by retroviral transduction of bone marrow stem cells with m157. In chimeric mice expressing m157, we observed a reduction in Ly49H+ NK cells in multiple tissues and less Ly49H on the cell surface. NK cells exposed to m157 during development appeared less mature, produced less interferon γ when stimulated through Ly49H, and were unable to kill m157-bearing target cells. After MCMV infection, these NK cells were severely impaired in their ability to proliferate. Thus, if immature NK cells encounter ligands for their activating receptors, regulatory mechanisms exist to keep these cells in an unresponsive state.


2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yingying Chen ◽  
Dan Lu ◽  
Alexey Churov ◽  
Rong Fu

Natural killer cells (NK cells) play an important role in innate immunity. NK cells recognize self and nonself depending on the balance of activating receptors and inhibitory receptors. After binding to their ligands, NK cell receptors trigger subsequent signaling conduction and then determine whether NK is activated or inhibited. Furthermore, NK cell response includes cytotoxicity and cytokine release, which is tightly related to the activation of NK cell-activating receptors and the inhibition of inhibitory receptors on the surfaces of NK cells. The expression and function of NK cell surface receptors also alter in virus infection, tumor, and autoimmune diseases and influence the occurrence and development of diseases. So, it is important to understand the mechanism of recognition between NK receptors and their ligands in pathological conditions and the signaling pathways of NK cell receptors. This review mainly summarizes the research progress on NK cell surface receptors and their signal pathways.


2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 95-95
Author(s):  
Christine Pasero ◽  
Gwenaelle Gravis ◽  
Mathilde Guerin ◽  
Palma Rocchi ◽  
Jeanne Thomassin ◽  
...  

95 Background: Immunotherapy is now investigated as a promising alternative treatment for patients (pts) with metastatic prostate cancer (PC). Natural killer (NK) cells are powerful effector cells with antitumoral activity and their role have been explored in solid tumors but not yet in prostate cancer. NK cell cytotoxicity is regulated by a balance between activating and inhibitory receptors. Here, we performed a restrospective study to evaluate the link between NK cells and the time of castration response in newly diagnosed PC patients with metastases. Methods: Newly diagnosed metastatic PC pts were divided according the time of castration response, with an 18-months cutoff value: 18 pts with long castration response (LCR, median = 64.6 months), and 14 pts with short castration response ([SCR] median = 11.2 months), with a median overall survival of 97.7 months and 33.8 months respectively. Circulating NK cells from these patients were studied by flow cytometry to evaluate the expression of activating receptors and the NK cell functionality. Results: We observed thatNK cells from LCR pts express higher levels of the maturation marker CD57 (43.3% vs. 23.3% positive cells, p= 0.002), the receptor CD16 involved in cytotoxicity (29,124 vs. 16,806 MFI, p= 0.02), and the activating receptors NKp46 and NKp30 (17.5 vs. 11.4 RMFI, p= 0.0146 , and 10.9 vs. 6.3 RMFI, p = 0.0128 respectively) than NK cells from SCR pts. This suggests that LCR pts have powerful NK cells. Indeed, NK cells from LCR pts are highly efficient in CD107 functional assay than NK cells from SCR pts (28.9% vs. 19.4%, p =0.002). In vitro blocking experiments show that NKp46 is precisely one of the NK cell receptors involved in the NK-mediated recognition of prostate tumor cells, thus higher expression of NKp46 would help to control PC progression. Conclusions: Together our results show for the first time that efficient NK cells are associated to a long response to castration and prolonged survival in newly diagnosed metastatic PC. NK cell receptors might be useful as predictive biomarkers in metastatic PC, to help in stratification of patients and to design NK cell–based immunotherapeutic strategies for PC.


Blood ◽  
2007 ◽  
Vol 110 (4) ◽  
pp. 1207-1214 ◽  
Author(s):  
Jeffrey Ward ◽  
Matthew Bonaparte ◽  
Jennifer Sacks ◽  
Jacqueline Guterman ◽  
Manuela Fogli ◽  
...  

AbstractThe ability of natural killer (NK) cells to kill virus-infected cells depends on the presence of ligands for activation receptors on the target cells. We found the presence of few, if any, NKp30 and NK46 ligands on T cell blasts infected with HIV, although NKp44 ligands were found on infected cells. HIV does induce the NKG2D ligands ULBP-1, -2, and -3. These ligands are involved in triggering NK cells to kill autologous HIV-infected cells, because interfering with the interaction between NKG2D, but not NKp46, on NK cells and its ligands on HIV-infected cells drastically reduced the lysis of infected cells. Interfering with the binding of the NK-cell coreceptors NTB-A and 2B4 to their ligands also decreased destruction by NK cells. The coreceptor ligands, NTB-A and CD48, were also found to be down-regulated during the course of HIV infection. Thus, ligands for NK-cell receptors are modulated during the course of HIV infection, which may greatly alter NK cells' ability to kill the infected cells.


2005 ◽  
Vol 79 (5) ◽  
pp. 2920-2930 ◽  
Author(s):  
Milena Hasan ◽  
Astrid Krmpotic ◽  
Zsolt Ruzsics ◽  
Ivan Bubic ◽  
Tihana Lenac ◽  
...  

ABSTRACT Both human and mouse cytomegaloviruses (CMVs) encode proteins that inhibit the activation of NK cells by down-regulating cellular ligands for the activating NK cell receptor NKG2D. Up to now, three ligands for the NKG2D receptor, named RAE-1, H60, and MULT-1, have been identified in mice. The resistance of mouse strains to murine CMV (MCMV) infection is determined by their ability to generate an effective NK cell response. The MCMV gene m152, a member of the m145 gene family, down-regulates the expression of RAE-1 in order to avoid NK cell control in vivo. Here we report that the m155 gene, another member of the m145 gene family, encodes a protein that interferes with the expression of H60 on the surfaces of infected cells. Deletion of the m155 gene leads to an only partial restoration of H60 expression on the cell surface, suggesting the involvement of another, so far unknown, viral inhibitor. In spite of this, an m155 deletion mutant virus shows NK cell-dependent attenuation in vivo. The acquisition of endo-β-N-acetylglucosaminidase H resistance and the preserved half-life of H60 in MCMV-infected cells indicate that the m155-mediated effect must take place in a compartment after H60 exits from the ERGIC-cis-Golgi compartment.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Stephanie Trittel ◽  
Benedict J. Chambers ◽  
Ulrike Heise ◽  
Carlos A. Guzmán ◽  
Peggy Riese

Abstract The contribution of natural killer (NK) cells to the clearance of hepatic viral infections is well recognized. The recently discovered heterogeneity of NK cell populations renders them interesting targets for immune interventions. Invariant natural killer T (iNKT) cells represent a key interaction partner for hepatic NK cells. The present study addressed whether characteristics of NK cells in the liver can be shaped by targeting iNKT cells. For this, the CD1d-binding pegylated glycolipid αGalCerMPEG was assessed for its ability to modulate the features of NK cells permanently or transiently residing in the liver. In vivo administration resulted in enhanced functionality of educated and highly differentiated CD27+ Mac-1+ NK cells accompanied by an increased proliferation. Improved liver homing was supported by serum-derived and cellular factors. Reduced viral loads in a mCMV infection model confirmed the beneficial effect of NK cells located in the liver upon stimulation with αGalCerMPEG. Thus, targeting iNKT cell-mediated NK cell activation in the liver represents a promising approach for the establishment of liver-directed immune interventions.


Blood ◽  
2012 ◽  
Vol 120 (18) ◽  
pp. 3729-3740 ◽  
Author(s):  
Alice C. N. Brown ◽  
Ian M. Dobbie ◽  
Juha-Matti Alakoskela ◽  
Ilan Davis ◽  
Daniel M. Davis

Abstract Natural killer (NK) cells secrete lytic granules to directly kill virus-infected or transformed cells and secrete cytokines to communicate with other cells. Three-dimensional super-resolved images of F-actin, lytic granules, and IFN-γ in primary human NK cells stimulated through different activating receptors reveal that both IFN-γ and lytic granules accumulated in domains where the periodicity of the cortical actin mesh at the synapse opened up to be penetrable. Ligation of some activating receptors alone (eg, CD16 or NKG2D) was sufficient to increase the periodicity of the actin mesh, but surprisingly, ligation of others (eg, NKp46 or CD2) was not sufficient to induce cortical actin remodeling unless LFA-1 was coligated. Importantly, influenza virus particles that can be recognized by NK cells similarly did not open the actin mesh but could if LFA-1 was coligated. This leads us to propose that immune cells using germline-encoded receptors to directly recognize foreign proteins can use integrin recognition to differentiate between free pathogens and pathogen-infected cells that will both be present in blood. This distinction would not be required for NK cell receptors, such as NKG2D, which recognize host cell–encoded proteins that can only be found on diseased cells and not pathogens.


2021 ◽  
Vol 218 (5) ◽  
Author(s):  
Maria Ferez ◽  
Cory J. Knudson ◽  
Avital Lev ◽  
Eric B. Wong ◽  
Pedro Alves-Peixoto ◽  
...  

Natural killer (NK) cell activation depends on the signaling balance of activating and inhibitory receptors. CD94 forms inhibitory receptors with NKG2A and activating receptors with NKG2E or NKG2C. We previously demonstrated that CD94-NKG2 on NK cells and its ligand Qa-1b are important for the resistance of C57BL/6 mice to lethal ectromelia virus (ECTV) infection. We now show that NKG2C or NKG2E deficiency does not increase susceptibility to lethal ECTV infection, but overexpression of Qa-1b in infected cells does. We also demonstrate that Qa-1b is down-regulated in infected and up-regulated in bystander inflammatory monocytes and B cells. Moreover, NK cells activated by ECTV infection kill Qa-1b–deficient cells in vitro and in vivo. Thus, during viral infection, recognition of Qa-1b by activating CD94/NKG2 receptors is not critical. Instead, the levels of Qa-1b expression are down-regulated in infected cells but increased in some bystander immune cells to respectively promote or inhibit their killing by activated NK cells.


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