scholarly journals The Human Cytomegalovirus Protein UL16 Mediates Increased Resistance to Natural Killer Cell Cytotoxicity through Resistance to Cytolytic Proteins

2003 ◽  
Vol 77 (8) ◽  
pp. 4539-4545 ◽  
Author(s):  
Jenny Odeberg ◽  
Helena Browne ◽  
Sunil Metkar ◽  
Christopher J. Froelich ◽  
Lars Brandén ◽  
...  
Keyword(s):  
Nk Cells ◽  
Human Cytomegalovirus ◽  
Deletion Mutant ◽  
Nk Cell ◽  
Granzyme B ◽  
Killer Cell ◽  
Target Cells ◽  
Natural Killer Cell Cytotoxicity ◽  
Hcmv Strain ◽  
Infected Cells

ABSTRACT Several reports have shown that human cytomegalovirus (HCMV)-infected cells are resistant to NK lysis. These studies have focused on receptor-ligand interactions, and different HCMV proteins have been indicated to mediate inhibitory NK signals. Here, we report that the HCMV protein UL16 is of major importance for the ability of HCMV-infected cells to resist NK cell-mediated cytotoxicity. Fibroblasts infected with the UL16 deletion mutant HCMV strain exhibited a 70% increased sensitivity to NK killing at 7 days postinfection compared to AD169-infected cells. Interestingly, HCMV-infected cells did not appear to engage inhibitory molecules on NK cells, since the levels of granzyme B were not reduced in supernatants obtained from NK cell cocultures with infected target cells compared to uninfected target cells. Furthermore, HCMV-infected cells, but not cells infected with the UL16 deletion mutant HCMV strain, exhibited a significantly increased resistance to the action of cytolytic proteins, including perforin, granzyme B, streptolysin O, and porcine NK lysin. In addition, fluorescence-activated cell sorting for UL16-positive transfected cells resulted in protection levels of 90% compared to control cells carrying the green fluorescent protein vector. Thus, the UL16 protein mediates an increased protection against the action of cytolytic proteins released by activated NK cells, possibly by a membrane-stabilizing mechanisms, rather than by delivering negative signals to NK cells.

scholarly journals The human cytomegalovirus protein UL147A downregulates the most prevalent MICA allele: MICA*008, to evade NK cell-mediated killing

2021 ◽  
Vol 17 (5) ◽  
pp. e1008807
Author(s):  
Einat Seidel ◽  
Liat Dassa ◽  
Corinna Schuler ◽  
Esther Oiknine-Djian ◽  
Dana G. Wolf ◽  
...  
Keyword(s):  
Nk Cells ◽  
Human Cytomegalovirus ◽  
Cell Activation ◽  
Hcmv Infection ◽  
Nk Cell ◽  
Innate Immune ◽  
Target Cells ◽  
Histocompatibility Complex ◽  
Immunosuppressed Patients ◽  
Infected Cells

Natural killer (NK) cells are innate immune lymphocytes capable of killing target cells without prior sensitization. One pivotal activating NK receptor is NKG2D, which binds a family of eight ligands, including the major histocompatibility complex (MHC) class I-related chain A (MICA). Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus causing morbidity and mortality in immunosuppressed patients and congenitally infected infants. HCMV encodes multiple antagonists of NK cell activation, including many mechanisms targeting MICA. However, only one of these mechanisms, the HCMV protein US9, counters the most prevalent MICA allele, MICA*008. Here, we discover that a hitherto uncharacterized HCMV protein, UL147A, specifically downregulates MICA*008. UL147A primarily induces MICA*008 maturation arrest, and additionally targets it to proteasomal degradation, acting additively with US9 during HCMV infection. Thus, UL147A hinders NKG2D-mediated elimination of HCMV-infected cells by NK cells. Mechanistic analyses disclose that the non-canonical GPI anchoring pathway of immature MICA*008 constitutes the determinant of UL147A specificity for this MICA allele. These findings advance our understanding of the complex and rapidly evolving HCMV immune evasion mechanisms, which may facilitate the development of antiviral drugs and vaccines.

scholarly journals HIV modulates the expression of ligands important in triggering natural killer cell cytotoxic responses on infected primary T-cell blasts

Blood ◽  
2007 ◽  
Vol 110 (4) ◽  
pp. 1207-1214 ◽  
Author(s):  
Jeffrey Ward ◽  
Matthew Bonaparte ◽  
Jennifer Sacks ◽  
Jacqueline Guterman ◽  
Manuela Fogli ◽  
...  
Keyword(s):  
T Cell ◽  
Hiv Infection ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Target Cells ◽  
Nk Cell Receptors ◽  
Infected Cells ◽  
Cytotoxic Responses

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.

scholarly journals The Lectin-like Receptor KLRE1 Inhibits Natural Killer Cell Cytotoxicity

2003 ◽  
Vol 197 (11) ◽  
pp. 1551-1561 ◽  
Author(s):  
Ingunn H. Westgaard ◽  
Erik Dissen ◽  
Knut M. Torgersen ◽  
Sasha Lazetic ◽  
Lewis L. Lanier ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Transmembrane Domain ◽  
Nk Cell ◽  
Transmembrane Protein ◽  
Killer Cell ◽  
Functional Characterization ◽  
Interleukin 2 ◽  
Target Cells ◽  
Natural Killer Cell Cytotoxicity

We report the cloning and functional characterization in the mouse and the rat of a novel natural killer (NK) cell receptor termed KLRE1. The receptor is a type II transmembrane protein with a COOH-terminal lectin-like domain, and constitutes a novel KLR family. Rat Klre1 was mapped to the NK gene complex. By Northern blot and flow cytometry using newly generated monoclonal antibodies, KLRE1 was shown to be expressed by NK cells and a subpopulation of CD3+ cells, with pronounced interstrain variation. Western blot analysis indicated that KLRE1 can be expressed on the NK cell surface as a disulphide-linked dimer. The predicted proteins do not contain immunoreceptor tyrosine-based inhibitory motifs (ITIMs) or a positively charged amino acid in the transmembrane domain. However, in a redirected lysis assay, the presence of whole IgG, but not of F(ab′)2 fragments of a monoclonal anti-KLRE1 antibody inhibited lysis of Fc-receptor bearing tumor target cells. Moreover, the tyrosine phosphatase SHP-1 was coimmunoprecipitated with KLRE1 from pervanadate-treated interleukin 2–activated NK cells. Together, our results indicate that KLRE1 may form a functional heterodimer with an as yet unidentified ITIM-bearing partner that recruits SHP-1 to generate an inhibitory receptor complex.

scholarly journals WF10 Stimulates NK Cell Cytotoxicity by Increasing LFA-1-Mediated Adhesion to Tumor Cells

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Louisa Kühne ◽  
Mathias Konstandin ◽  
Yvonne Samstag ◽  
Stefan Meuer ◽  
Thomas Giese ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Target Cells ◽  
Dependent Manner ◽  
Cell Cytotoxicity ◽  
Natural Killer Cell Cytotoxicity ◽  
Nk Cell Cytotoxicity

The redox-active chlorite-based drug WF10 (Immunokine) was shown to have modulatory effects on both the innate and adaptive immune systemin vitroandin vivo. Animal studies suggest that WF10 enhances immunity against tumors. One possible explanation for such an effect is that WF10 stimulates natural killer cell cytotoxicity against malignant cells. Here, we show that WF10 regulates human NK cell cytotoxicity in a time-dependent manner, following an S-shaped kinetic with an initial stimulation of activity followed by a decrease in activity relative to the untreated controls. WF10 does not activate NK cells on its own but co-stimulates NK cell activation mediated by different activating receptors. This is mediated by enhancing NK cell adhesion to target cells through promoting the activation of the integrin LFA-1. These data demonstrate a direct effect of WF10 on the cytotoxicity of human NK cells.

scholarly journals The human cytomegalovirus protein UL147A downregulates the most prevalent MICA allele: MICA*008, to evade NK cell-mediated killing

2020 ◽  
Author(s):  
Einat Seidel ◽  
Liat Dassa ◽  
Esther Oiknine-Djian ◽  
Dana G. Wolf ◽  
Vu Thuy Khanh Le-Trilling ◽  
...  
Keyword(s):  
Nk Cells ◽  
Human Cytomegalovirus ◽  
Immune Evasion ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Activity ◽  
Asymptomatic Infection ◽  
Target Cells ◽  
Hcmv Disease ◽  
Infected Cells

AbstractNatural killer (NK) cells are innate immune lymphocytes capable of killing target cells without prior sensitization. NK cell activity is regulated by signals received from activating and inhibitory receptors. One pivotal activating NK receptor is NKG2D, which binds a family of eight ligands, including the major histocompatibility complex (MHC) class I-related chain A (MICA). Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus causing morbidity and mortality in immunosuppressed patients and congenitally infected infants. HCMV encodes multiple antagonists of NK cell activation, including many mechanisms targeting MICA. However, only one of these mechanisms counters the most prevalent MICA allele, MICA*008. Here, we discover that a hitherto uncharacterized HCMV protein, UL147A, specifically targets MICA*008 to proteasomal degradation, thus hindering the elimination of HCMV-infected cells by NK cells. Mechanistic analyses disclose that the non-canonical GPI anchoring pathway of immature MICA*008 constitutes the determinant of UL147A specificity for this MICA allele. These findings advance our understanding of the complex and rapidly evolving HCMV immune evasion mechanisms, which may facilitate the development of antiviral drugs and vaccines.Author SummaryHuman cytomegalovirus (HCMV) is a common pathogen that usually causes asymptomatic infection in the immunocompetent population, but the immunosuppressed and fetuses infected in utero suffer mortality and disability due to HCMV disease. Current HCMV treatments are limited and no vaccine has been approved, despite significant efforts. HCMV encodes many genes of unknown function, and virus-host interactions are only partially understood. Here, we discovered that a hitherto uncharacterized HCMV protein, UL147A, downregulates the expression of an activating immune ligand allele named MICA*008, thus hindering the elimination of HCMV-infected cells. Elucidating HCMV immune evasion mechanisms could aid in the development of novel HCMV treatments and vaccines. Furthermore, MICA*008 is a highly prevalent allele implicated in cancer immune evasion, autoimmunity and graft rejection. In this work we have shown that UL147A interferes with MICA*008’s poorly understood, nonstandard maturation pathway. Study of UL147A may enable manipulation of its expression as a therapeutic measure against HCMV.

scholarly journals Recognition of virus-infected cells by natural killer cell clones is controlled by polymorphic target cell elements.

1993 ◽  
Vol 178 (3) ◽  
pp. 961-969 ◽  
Author(s):  
M S Malnati ◽  
P Lusso ◽  
E Ciccone ◽  
A Moretta ◽  
L Moretta ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Target Cell ◽  
Nk Cell ◽  
Class I ◽  
Target Cells ◽  
Cell Recognition ◽  
Infected Cells ◽  
Nk Cell Recognition

Natural killer (NK) cells provide a first line of defense against viral infections. The mechanisms by which NK cells recognize and eliminate infected cells are still largely unknown. To test whether target cell elements contribute to NK cell recognition of virus-infected cells, human NK cells were cloned from two unrelated donors and assayed for their ability to kill normal autologous or allogeneic cells before and after infection by human herpesvirus 6 (HHV-6), a T-lymphotropic herpesvirus. Of 132 NK clones isolated from donor 1, all displayed strong cytolytic activity against the NK-sensitive cell line K562, none killed uninfected autologous T cells, and 65 (49%) killed autologous T cells infected with HHV-6. A panel of representative NK clones from donors 1 and 2 was tested on targets obtained from four donors. A wide heterogeneity was observed in the specificity of lysis of infected target cells among the NK clones. Some clones killed none, some killed only one, and others killed more than one of the different HHV-6-infected target cells. Killing of infected targets was not due to complete absence of class I molecules because class I surface levels were only partially affected by HHV-6 infection. Thus, target cell recognition is not controlled by the effector NK cell alone, but also by polymorphic elements on the target cell that restrict NK cell recognition. Furthermore, NK clones from different donors display a variable range of specificities in their recognition of infected target cells.

scholarly journals The Bw4 public epitope of HLA-B molecules confers reactivity with natural killer cell clones that express NKB1, a putative HLA receptor.

1995 ◽  
Vol 181 (3) ◽  
pp. 1133-1144 ◽  
Author(s):  
J E Gumperz ◽  
V Litwin ◽  
J H Phillips ◽  
L L Lanier ◽  
P Parham
Keyword(s):  
Monoclonal Antibody ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Inhibitory Effect ◽  
Glycosylation Site ◽  
Class I ◽  
Target Cells ◽  
Cell Clones

Although inhibition of natural killer (NK) cell-mediated lysis by the class I HLA molecules of target cells is an established phenomenon, knowledge of the features of class I molecules which induce this effect remains rudimentary. Using class I alleles HLA-B*1502 and B*1513 which differ only at residues 77-83 which define the Bw4 and Bw6 serological epitopes, we tested the hypothesis that the presence of the Bw4 epitope on class I molecules determines recognition by NKB1+ NK cells. HLA-B*1513 possesses the Bw4 epitope, whereas B*1502 has the Bw6 epitope. Lysis by NKB1+ NK cell clones of transfected target cells expressing B*1513 as the only HLA-A, -B, or -C molecule was inhibited, whereas killing of transfectants expressing B*1502 was not. Addition of an an anti-NKB1 monoclonal antibody reconstituted lysis of the targets expressing B*1513, but did not affect killing of targets bearing B*1502. The inhibitory effect of B*1513 could be similarly prevented by the addition of an anti-class I monoclonal antibody. These results show that the presence of the Bw4 epitope influences recognition of HLA-B molecules by NK cells that express NKB1, and suggest that the NKB1 molecule may act as a receptor for Bw4+ HLA-B alleles. Sequences outside of the Bw4 region must also affect recognition by NKB1+ NK cells, because lysis of transfectants expressing HLA-A*2403 or A*2501, which possess the Bw4 epitope but are in other ways substantially different from HLA-B molecules, was not increased by addition of the anti-NKB1 antibody. Asparagine 86, the single site of N-linked glycosylation on class I molecules, is in close proximity to the Bw4/Bw6 region. The glycosylation site of the Bw4-positive molecule B*5801 was mutated, and the mutant molecules tested for inhibition of NKB1+ NK cells. Inhibition that could be reversed by addition of the anti-NKB1 monoclonal antibody was observed, showing the presence of the carbohydrate moiety is not essential for class I recognition by NKB1+ NK cell clones.

scholarly journals Ly49P recognition of cytomegalovirus-infected cells expressing H2-Dk and CMV-encoded m04 correlates with the NK cell antiviral response

2009 ◽  
Vol 206 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Agnieszka Kielczewska ◽  
Michal Pyzik ◽  
Tianhe Sun ◽  
Astrid Krmpotic ◽  
Melissa B. Lodoen ◽  
...  
Keyword(s):  
Nk Cells ◽  
Deletion Mutant ◽  
Viral Infections ◽  
Nk Cell ◽  
Cell Receptor ◽  
Major Histocompatability Complex ◽  
Wild Type ◽  
Mcmv Infection ◽  
Host Protection ◽  
Infected Cells

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.

scholarly journals Suppression of Natural Killer Cell Cytotoxicity in Postpartum Women

2013 ◽  
Vol 16 (3) ◽  
pp. 320-326 ◽  
Author(s):  
Maureen W. Groer ◽  
Nagwa El-Badri ◽  
Julie Djeu ◽  
S. Nicole Williams ◽  
Bradley Kane ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Postpartum Period ◽  
Nk Cell ◽  
Killer Cell ◽  
Control Group ◽  
Postpartum Women ◽  
Cell Cytotoxicity ◽  
Natural Killer Cell Cytotoxicity ◽  
Nk Cytotoxicity

Little is known about the recovery of the immune system from normal pregnancy and whether the postpartum period is a uniquely adapted immune state. This report extends previous observations from our group of decreased natural killer (NK) cell cytotoxicity in the postpartum period. NK cytotoxicity was measured from 1 week through 9 months postpartum. In addition, NK cytotoxicity was assayed in the presence or absence of pooled plasmas collected from either postpartum or nonpostpartum women. Samples of cells were stained for inhibitory receptors and analyzed by flow cytometry. NK cytotoxicity remained decreased in postpartum women compared to controls through the first 6 postpartum months, returned to normal levels by 9 months, and remained normal at 12 months. NK cytotoxicity during the first 6 months was further inhibited by the addition of pooled plasma to NK cultures from postpartum women, but the addition of pooled plasma from the control group did not affect that group’s NK cultures. There were differences in inhibitory receptor staining between the two groups, with decreased CD158a and CD158b and increased NKG2A expression on postpartum NK cells during the first 3 postpartum months. These data suggest that NK cytotoxicity postpartum inhibition lasts 6 months and is influenced by unidentified postpartum plasma components. The effect may also involve receptors on NK cells.

IPH2101, a Novel Anti-Inhibitory KIR Monoclonal Antibody, and Lenalidomide Combine to Enhance the Natural Killer (NK) Cell Versus Multiple Myeloma (MM) Effect.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3870-3870 ◽  
Author(s):  
Don Benson ◽  
Courtney E Bakan ◽  
Shuhong Zhang ◽  
Lana Alghothani ◽  
Jing Liang ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Nk Cells ◽  
Tumor Cells ◽  
Nk Cell ◽  
Phase 1 ◽  
Granzyme B ◽  
Cell Activity ◽  
Target Cells ◽  
Nk Cell Activity ◽  
Immune Complex Formation

Abstract Abstract 3870 Poster Board III-806 Background NK cell activity against tumor cells is regulated by a balance of inhibitory and activating signals mediated by receptors on NK cells that recognize inhibitory and activating ligands expressed by cancer cells. IPH2101 (1-7F9) is a novel monoclonal anti-inhibitor KIR blocking antibody that has been shown to augment NK cell function against MM targets. Moreover, lenalidomide has been shown to expand and activate NK cells in vivo and in vitro. We have previously reported that the combination of IPH2101 and lenalidomide enhances NK cell mediated cytotoxicity against MM cells compared to each agent alone (Zhang et al., AACR 2009). We expand our studies to investigate potential mechanisms for the enhancement of NK cell activity by the combination of IPH2101 and lenalidomide. Methods The effects of IPH2101 and lenalidomide alone and in combination were studied using primary human NK cells from healthy donors as well as from MM patients. The MM cell lines U266 and RPMI 8226 as well as primary tumor cells from marrow aspirates of MM patients served as target cells. The effect of lenalidomide on MM activating and inhibitory ligand expression was studied by flow cytometry. NK cell trafficking was investigated with standard transwell plate migration assay. Immune complex formation between NK cell effectors and MM tumor targets was characterized by flow cytometry in control conditions and with NK cells pre-treated with IPH2101 and lenalidomide. The effects of IPH2101 and lenalidomide were studied regarding interferon-gamma and granzyme B production by ELISPOT and target-specific cytotoxicity studies were conducted to complement effector-based assays. Results IPH2101 (30 ug/ml) significantly enhanced cytotoxicity against U266 cells and primary MM tumor cells by both purified NK cells at effector:target (E:T) ratios of 10:1 or less, and also of freshly isolated peripheral blood mononuclear cells (PBMC) at E:T ratios of 60:1 or less, from more than 10 random donors. In addition, treatment of PBMC with 5-10 μmol/L lenalidomide for 72h without interleukin (IL)-2 increased NK cell lysis of U266. Treatment of PBMC from normal donors did not enhance the expression of the NK receptors KIR, NKG2D, NCR, TRAIL, and DNAM-1. Incubation of U266 cells with lenalidomide (5 uM) for 3-5 days resulted in significant enhancement of cytotoxicity by normal donor NK cells. This was associated with upregulation of the activating ligands, MICA, ULBP-2, DR4, and CD112. Using blocking antibodies to NKG2D, TRAIL, and DNAM-1, lenalidomide enhancement of MM cell killing was abrogated indicating the importance of the modulation of the ligands to the latter receptors by lenalidomide. Although IPH2101 and lenalidomide did not significantly increase NK cell migration into normal media, migration was enhanced 2.98-fold (+/− 0.36, p < 0.05) towards U266 cell targets (n= 3, p < 0.05) and MM patient serum 3.2-fold (+/− 0.4, n=3, p < 0.05). IPH2101 and lenalidomide also led to a 2.3-fold (+/− 0.43, p < 0.05) increase in immune complex formation between NK cells and MM tumor cells. IPH2101 and lenalidomide also augmented NK cell interferon gamma production against MM (control mean 303 spots/well +/− 13 versus 525 +/− 83, n=3, p < 0.05) and granzyme B production (control mean 115 +/− 98 versus 449 +/−72, n=3, p < 0.05). Importantly, in all experiments described herein, the effects of IPH2101 and lenalidomide together were greater than either agent alone. Conclusions Taken together, our data suggest that IPH2101 and lenalidomide may exert complementary mechanisms on both effector and target cells to enhance NK cell mediated killing of MM cells. Moreover, these agents have no predicted clinical cross-toxicities. A single-agent phase 1 clinical trial of IPH2101 has shown the mAb to be safe and well tolerated in MM patients. These findings support a phase 1/2 clinical trial of IPH2101 with lenalidomide as a first dual-innate immunotherapy for patients with MM. Disclosures: Andre: Innate Pharma: Employment. Squiban:Innate pharma: Employment. Romagne:Innate Pharma: Employment.

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