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NK Cell Cytotoxicity (nk + cell_cytotoxicity)
Selected AbstractsFetal Ethanol Exposure Disrupts the Daily Rhythms of Splenic Granzyme B, IFN- ,, and NK Cell Cytotoxicity in AdulthoodALCOHOLISM, Issue 6 2006Alvaro Arjona Background: Circadian (and daily) rhythms are physiological events that oscillate with a 24-hour period. Circadian disruptions may hamper the immune response against infection and cancer. Several immune mechanisms, such as natural killer (NK) cell function, follow a daily rhythm. Although ethanol is known to be a potent toxin for many systems in the developing fetus, including the immune system, the long-term effects of fetal ethanol exposure on circadian immune function have not been explored. Methods: Daily rhythms of cytotoxic factors (granzyme B and perforin), interferon- , (IFN- ,), and NK cell cytotoxic activity were determined in the spleens of adult male rats obtained from mothers who were fed during pregnancy with chow food or an ethanol-containing liquid diet or pair-fed an isocaloric liquid diet. Results: We found that adult rats exposed to ethanol during their fetal life showed a significant alteration in the physiological rhythms of granzyme B and IFN- , that was associated with decreased NK cell cytotoxic activity. Conclusion: These data suggest that fetal ethanol exposure causes a permanent alteration of specific immune rhythms that may in part underlie the immune impairment observed in children prenatally exposed to alcohol. [source] Elevated NK Cell Cytotoxicity, CD158a Expression in NK Cells and Activated T Lymphocytes in Peripheral Blood of Women with IVF FailuresAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010Viktor P. Chernyshov Citation Chernyshov VP, Sudoma IO, Dons'koi BV, Kostyuchyk AA, Masliy YV. Elevated NK cell cytotoxicity, CD158a expression in NK cells and activated T lymphocytes in peripheral blood of women with IVF failures. Am J Reprod Immunol 2010; 64: 58,67 Problem, The aim of this study was to evaluate the role of elevated natural killer cytotoxicity (NKc) in women with multiple implantation failures (IF) in vitro fertilization,embryo transfer (IVF,ET) cycles. Methods of study, Seventy-nine antiphospholipid antibodies-negative women with IF including 33 women with elevated NKc were selected for investigation. K-562 cell line was used to evaluate NKc. Lymphocyte subsets, intracellular cytokines [interferon (IFN)-,, interleukin (IL)-4, tumour necrosis factor, IL-10], expression of activating markers [CD69, human leukocyte antigen (HLA)-DR], CD8, KIR (CD158a), CD95, and chemokine receptors (CXCR3, CCR4) were estimated by flow cytometry. Results, In women with IF, levels of NKc were higher than in IVF successful women. IF was associated with higher expression of CD8, CD158a, and HLA-DR in NK cells, activating markers in T lymphocytes, and lower levels of CCR4+ and IL-4+ T lymphocyte subsets. Predictive value of single elevated NKc for IVF success was 0.85, but addition of two other abnormal parameters resulted in its decrease to <0.39. Conclusions, Elevated NKc is negative factor, though not critical for implantation in IVF cycles. Immune mechanism of IVF failure includes not only elevated NKc but also some other factors, such as elevated expression of CD8 and CD158a on NK cells, T lymphocyte activation, and diminished T helper 2 parameters. [source] Impaired differentiation and cytotoxicity of natural killer cells in systemic lupus erythematosusARTHRITIS & RHEUMATISM, Issue 6 2009Yong-Wook Park Objective To determine the cytotoxicity of natural killer (NK) cells and the level of differentiation of hematopoietic stem cells (HSCs) into NK cells in systemic lupus erythematosus (SLE). Methods Patients with SLE (n = 108), rheumatoid arthritis (RA; n = 90), Behçet's disease (n = 39), or ankylosing spondylitis (n = 41) and healthy control subjects (n = 173) were enrolled in the study. NK cell levels, NK cell cytotoxicities, and lymphokine-activated killer (LAK) activities against K562 cells were measured by flow cytometry. Gene expression was assessed by reverse transcription,polymerase chain reaction. NK cells were differentiated from peripheral blood and bone marrow HSCs in vitro. Results Percentages and absolute numbers of NK cells, cytotoxicities, and LAK activities were significantly lower in the peripheral blood of SLE and RA patients than in that of healthy controls. In particular, this NK cell deficiency was more prominent in patients with lupus nephritis and those with thrombocytopenia. Notably, purified NK cells derived from SLE patients, but not RA patients, were found to have lower cytotoxicities and LAK activities than those from healthy controls. This defect of NK cells in SLE patients was found to be related to lower numbers of NK precursors and to the down-regulation of perforin and granzyme in NK cells. The proliferative capacity of HSCs, the percentages of NK cells differentiated from HSCs, and NK cell cytotoxicities were significantly lower in SLE patients. Conclusion In SLE patients, circulating levels of NK cells were diminished and their cytotoxicities were impaired. Furthermore, the differentiation of HSCs into NK cells was found to be defective. These abnormalities possibly contribute to immune system dysregulation in SLE. [source] The IFN regulatory factor 7-dependent type I IFN response is not essential for early resistance against murine cytomegalovirus infectionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2009Christian Steinberg Abstract IFN regulatory factor 7 (IRF7) has been described as the master regulator of type I IFN responses and has been shown to be critical for innate antiviral immunity in vivo. In addition to type I IFN, NK cell responses are involved in the control of viral replication during acute viral infection. To investigate the role of IRF7 in the context of a viral infection that induces a strong NK cell response, the murine cytomegalovirus (MCMV) infection model was used. WT, IRF7-deficient and IRF3/IRF7-double deficient mice were infected with MCMV. The systemic IFN-, response to MCMV was entirely dependent on IRF7, but independent of IRF3. However, peak IFN-, production during MCMV infection was not affected by the lack of IRF7 or both IRF7 and IRF3. Despite the complete lack of IFN-, production IRF7- and IRF3/IRF7-deficient mice were surprisingly efficient in controlling MCMV replication and were only modestly more susceptible to MCMV infection than WT mice. NK cell cytotoxicity was unimpaired and NK cell IFN-, production was enhanced in IRF7-deficient mice correlating with increased levels of bioactive IL-12. Owing to these compensatory mechanisms IRF7-dependent antiviral immune responses were not essential for resistance against acute MCMV infection in vivo. [source] Modulation of 2B4 (CD244) activity and regulated SAP expression in human NK cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2007Johanna Endt Abstract The adapter protein SAP is important for the signal transduction of the family of SLAM-related receptors (SRR), which have important immune-modulating functions. The importance of SAP and SRR for a functional immune reaction becomes obvious in patients suffering from X-linked lymphoproliferative disease, which is characterized by non-functional SAP. Here we investigate the regulation of SAP expression in human NK cells. We demonstrate that SAP mRNA expression and protein levels are low in freshly isolated resting NK cells. IL-2 stimulation leads to an up-regulation of SAP expression, which can be enhanced by IL-12, the stimulation of TLR3 by polyinosinic-polycytidylic acid (poly(I:C))and to a lesser extent by IFN-,. EAT-2, a SAP-related adapter protein, is already detectable in resting NK cells and does not change its expression after IL-2 stimulation. The regulation of SAP has functional consequences for the stimulation of NK cell cytotoxicity by 2B4. In resting NK cells, 2B4 stimulation can only enhance NK cell lysis when co-triggered with other activating NK cell receptors. In IL-2-activated NK cells with high SAP expression the triggering of 2B4 alone is sufficient to induce NK cell cytotoxicity, demonstrating a correlation between the regulated SAP expression and the function of 2B4. [source] Ganglioside GD3 expression on target cells can modulate NK cell cytotoxicity via siglec-7-dependent and -independent mechanismsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2003Gavin Nicoll Abstract Siglec-7 is a sialic acid binding receptor with inhibitory potential, expressed on human NK cells and monocytes. It has an unusual binding preference for ,2,8-linked disialic acids, such as those displayed by ganglioside GD3. Here we have investigated whether siglec-7-GD3 interactions are able to modulate NK cell cytotoxicity. Using synthetic polyacrylamide glycoprobes, siglec-7 was found to be masked at the NK cell surface but it could be unmasked by sialidase treatment of NK cells. GD3 synthase-transfected P815 target cells expressed high levels of GD3 and bound strongly to recombinant siglec-7-Fc protein. Surprisingly, GD3 synthase-transfected P815 cells were killed more effectively by untreated cells in a siglec-7-independent manner. However, following sialidase treatment of NK cells, a siglec-7-dependent inhibition of killing was observed. These findings have important implications for NK cell cytotoxicity against tumor cells like melanoma that express high levels of GD3 ganglioside. [source] Amelioration of doxorubicin-induced myocardial oxidative stress and immunosuppression by grape seed proanthocyanidins in tumour-bearing miceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2005Xiao-Yu Zhang We have investigated the protective effects of grape seed proanthocyanidins on doxorubicin-induced toxicity in tumour-bearing mice. The intraperitoneal administration of doxorubicin (2 mg kg,1 every other day, cumulative dosage for 18 mg kg,1) significantly inhibited the growth of sarcoma 180, and induced myocardial oxidative stress with decreased superoxide dismutase and glutathione peroxidase activity while increasing malondialdehyde formation in the heart or serum. Doxorubicin-induced myocardial oxidative stress also reduced lactate dehydrogenase and creatine kinase activity in the heart and elevated their levels in the serum. Doxorubicin also affected immune functions of tumour-bearing mice with significantly decreased interleukin-2 (IL-2) and interferon-, (INF-,) production, and slightly decreased natural killer (NK) cell cytotoxicity, lymphocyte proliferation and CD4+/CD8+ ratio. It markedly increased the percentages of cytotoxic T cells (CD3+CD8+), helper T cells (CD3+CD4+), IL-2R+CD4+, and IL-2R+ cells as compared with untreated tumour-bearing mice. The intragastric administration of proanthocyanidin (200 mg kg,1 daily) significantly inhibited tumour growth, and increased NK cell cytotoxicity, lymphocyte proliferation, CD4+/CD8+ ratio, IL-2 and INF-, production. Moreover, proanthocyanidin strongly enhanced the anti-tumour effect of doxorubicin and the above immune responses, and completely eliminated myocardial oxidative stress induced by doxorubicin. In conclusion, intragastric administration of proanthocyanidin could enhance the anti-tumour activity of doxorubicin and ameliorate doxorubicin-induced myocardial oxidative stress and immunosuppression in tumour-bearing mice. [source] Lipid solubility- and concentration-dependent attenuation of in vitro natural killer cell cytotoxicity by local anestheticsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2002J. Krog Background: Natural killer (NK) cells constitute an essential component of the innate immune system in the defence against infected and malignant cells. In this study the in vitro effect on NK cell activity of three different local anesthetics with different lipid solubility was investigated. Methods: Venous blood from seven healthy volunteers was incubated with three amide local anesthetics with three different concentrations of lipid solubility: lidocaine 0.50, 1.00 and 2.00 mg/ml, ropivacaine 0.375, 0.75 and 1.50 mg/ml, and bupivacaine 0.25, 0.50 and 1.00 mg/ml. After 1 h of incubation, mononuclear cells were isolated and cryopreserved until tested for NK cell cytotoxicity in a 4-h 51Cr-release assay against K-562 target cells. Natural killer cell cytotoxicity of mononuclear cells incubated with isotonic saline was used as the control. Results: A significant suppression in NK cell cytotoxicity was demonstrated for all three local anesthetic agents when the NK cell cytotoxicity was compared with the cytotoxicity estimated after incubation with the isotonic saline (P<0.004). Moreover a significant lipid solubility-dependent effect (P=0.0001) as well as an overall concentration-dependent effect (P<0.0001) on the NK cell cytotoxicity was found. Conclusion: The results of the present in vitro study suggest a negative association between the estimated NK cell cytotoxicity and the lipid solubility as well as the concentrations of the three local anesthetic agents tested. [source] Elevated NK Cell Cytotoxicity, CD158a Expression in NK Cells and Activated T Lymphocytes in Peripheral Blood of Women with IVF FailuresAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010Viktor P. Chernyshov Citation Chernyshov VP, Sudoma IO, Dons'koi BV, Kostyuchyk AA, Masliy YV. Elevated NK cell cytotoxicity, CD158a expression in NK cells and activated T lymphocytes in peripheral blood of women with IVF failures. Am J Reprod Immunol 2010; 64: 58,67 Problem, The aim of this study was to evaluate the role of elevated natural killer cytotoxicity (NKc) in women with multiple implantation failures (IF) in vitro fertilization,embryo transfer (IVF,ET) cycles. Methods of study, Seventy-nine antiphospholipid antibodies-negative women with IF including 33 women with elevated NKc were selected for investigation. K-562 cell line was used to evaluate NKc. Lymphocyte subsets, intracellular cytokines [interferon (IFN)-,, interleukin (IL)-4, tumour necrosis factor, IL-10], expression of activating markers [CD69, human leukocyte antigen (HLA)-DR], CD8, KIR (CD158a), CD95, and chemokine receptors (CXCR3, CCR4) were estimated by flow cytometry. Results, In women with IF, levels of NKc were higher than in IVF successful women. IF was associated with higher expression of CD8, CD158a, and HLA-DR in NK cells, activating markers in T lymphocytes, and lower levels of CCR4+ and IL-4+ T lymphocyte subsets. Predictive value of single elevated NKc for IVF success was 0.85, but addition of two other abnormal parameters resulted in its decrease to <0.39. Conclusions, Elevated NKc is negative factor, though not critical for implantation in IVF cycles. Immune mechanism of IVF failure includes not only elevated NKc but also some other factors, such as elevated expression of CD8 and CD158a on NK cells, T lymphocyte activation, and diminished T helper 2 parameters. [source] ORIGINAL ARTICLE: Correlation Between Natural Cytotoxicity Receptors and Intracellular Cytokine Expression of Peripheral Blood NK Cells in Women with Recurrent Pregnancy Losses and Implantation FailuresAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2009Atsushi Fukui Problem, Natural cytotoxicity receptors (NCRs) are unique markers, which regulate NK cell cytotoxicity and cytokine production. We investigated whether women with recurrent pregnancy losses (RPLs) and implantation failures have aberrant correlation between NCRs and intracellular cytokine expression of NK cells. Method of study, Peripheral blood NK cells (CD56dim and CD56bright) were analyzed for NCRs (NKp46, NKp44 and NKp30) and cytokine expression (TNF-,, IFN-,, IL-4, IL-10) using flow cytometry in RPL (n = 22), implantation failures (n = 23) or controls (n = 15). Results, In type 1 cytokine studies, CD56bright/NKp30+ cells in controls (r = 0.696, P < 0.05) were positively correlated with CD56bright/IFN-,+/TNF-,+ cells. CD56bright/NKp46+ cells in implantation failures (r = ,0.76, P < 0.01) were negatively correlated with CD56bright/IFN-,+/TNF-,, cells. RPL did not have any correlation. In type 2 cytokine studies, CD56+/NKp46+ cells (r = 0.758, P < 0.01) and CD56+/NKp30+ cells (r = 0.637, P < 0.05) were positively correlated with CD56bright/IL-4+/IL-10+ cells in controls. CD56+/NKp30+ cells in implantation failures (r = ,0.778, P < 0.05) were negatively correlated with CD56bright/IL-10+/IL-4+ cells. There were no correlations in RPL. Conclusion, Recurrent pregnancy losses and implantation failures have lack of, or negative correlation between NCRs and intracellular cytokines expression. This observation suggests that excessive pro-inflammatory cytokine expression in NK cells in RPL and implantation failures may be exerted through the NCRs or interruption of signal transduction processes. [source] ORIGINAL ARTICLE: A High Dose of Intravenous Immunoglobulin Increases CD94 Expression on Natural Killer Cells in Women with Recurrent Spontaneous AbortionAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2009Shigeki Shimada Problem, A high dose of intravenous immunoglobulin (HIVIg) therapy is effective in various diseases such as autoimmune diseases, and also is expected to have efficacy in recurrent spontaneous abortion (RSA). The aim of this study was to understand immunological mechanisms of this therapy. Method of study, By flowcytometric analyses, we examined phenotypic changes of a variety of immunological cells including natural killer (NK) cells, cytotoxic T cells, regulatory T cells and macrophages in peripheral blood of RSA women with HIVIg therapy (n = 8). Results, Expression percentages of inhibitory CD94 on NK cells significantly (P = 0.01) increased after the therapy (58.8 ± 21.4% versus 71.0 ± 17.6%). Conclusion, Mechanisms of possible efficacy of HIVIg therapy for RSA may include enhancement of CD94 expression and subsequent suppression of NK cell cytotoxicity. [source] ORIGINAL ARTICLE: Suppression of Mamu-AG by RNA InterferenceAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2009Jessica G. Drenzek Problem, The role of placental major histocompatibility complex (MHC) class I molecules in pregnancy is not well understood. Mamu-AG, the rhesus monkey homology of human leukocyte antigen (HLA)-G expressed in the human placenta, was targeted for degradation by RNA interference (RNAi), a powerful tool to aid in determining gene function, to determine the effect that this knockdown has on NK cell function. Method of study, A series of potential target short hairpin RNA (shRNA) sequences to suppress Mamu-AG expression was screened, which identified an optimal sequence to use in transfection experiments. Knockdown in two different Mamu-AG-expressing cell lines was measured by flow cytometry. Cytotoxicity assays were performed to correlate Mamu-AG expression with NK cell cytotoxicity. Results, Decreased expression of Mamu-AG by short interfering RNA (siRNA) (70,80%) in cell types tested was associated with increased lysis of Mamu-AG target cells. Conclusion, Target sequences have been identified that knocked down Mamu-AG expression by RNAi and increased lysis by NK cells. This supports the concept that NK cell receptors recognize this placental non-classical MHC class I molecule. [source] Inhibition of term decidual NK cell cytotoxicity by soluble HLA-G1AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5-6 2006Tobias G. Poehlmann Objectives, Soluble (s)HLA-G1 is produced by trophoblast cells. Aim was to analyze the capacities and mechanisms of sHLA-G1 to regulate interleukin (IL)-2-induced cytotoxicity of natural killer (NK) cells from human deciduas. Methods, Natural killer cells were isolated from decidual layers of term placentae, stimulated or not with IL-2 and supplemented with various concentrations of recombinant soluble HLA-G1 (sHLA-G1). For NK cell cytotoxicity assays, K562 cells were used as targets. Expression of signal transducer and activator of transcription 3 (STAT3) and perforin was analyzed by Western blotting. Apoptosis was examined by assessment of poly(ADP-ribose) polymerase cleavage. NK cells were analyzed by flow cytometry for IL-2receptor- , (IL-2R,; CD25) and transferrin receptor CD71 expression. Results, Interleukin-2 increases CD71, STAT3, perforin expression and cytotoxic potential of NK cells. Expression of CD71, STAT3 and perforin decreased simultaneously with cytotoxicity and dose-dependently when sHLA-G1 (1.6 ,g/mL,1.6 ng/mL) was added to IL-2 stimulated cultures. sHLA-G1 did not induce apoptosis and CD25 expression was not affected. Conclusion, Interleukin-2R, expression is not controlled by sHLA-G1, but its signal transducer STAT3 as well as several downstream effects, such as perforin expression, proliferation and cytotoxicity. The control of STAT3 bioavailability through sHLA-G1 may be a key regulator of the mentioned effects. [source] 1141154113 Expression of natural cytotoxicity receptors in peripheral blood NK cell subsets of women with recurrent spontaneous abortions (RSA) or implantation failuresAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2006A Fukui Problem:, Natural Cytotoxicity Receptors (NCRs) are unique markers of NK cells and regulate NK cell cytotoxicity and cytokine production. a2V-ATPase is expressed in the cell membrane and can regulate the pH of the extracellular environment, which might facilitate NK cell killing or cytokine secretion. In this preliminary study we evaluated the expression of NCRs and a2V-ATPase in peripheral blood NK cells of women with RSA or implantation (IVF-ET) failures. Method of Study:, Peripheral blood was obtained from women with RSA (n = 10), or IVF-ET failures (n = 9). CD56dim and CD56bright NK cells were analyzed for the expression of NCRs (NKp46, NKp44 and NKp30) and a2V-ATPase using flow cytometry. Results:, For women with RSA, there were significant differences in the expression of NKp46 between CD56dim (36.9 ± 30.2) and CD56bright (76.0 ± 27.5) (P < 0.01), of NKp30 between CD56dim (30.9 ± 25.7) and CD56bright (55.8 ± 29.5) (P < 0.01), and of a2V-ATPase between CD56dim (1.0 ± 0.9) and CD56bright (23.2 ± 15.1) (P < 0.01) NK cells. For women with IVF-ET failures, there were significant differences in the expression of NKp46 between CD56dim (39.5 ± 21.5) and CD56bright (78.8 ± 26.0) (P < 0.01), of NKp30 between CD56dim (27.2 ± 17.9) and CD56bright (45.2 ± 29.8) (P < 0.05), and of a2V-ATPase between CD56dim (1.6 ± 1.4) and CD56bright (21.2 ± 16.5) (P < 0.01) NK cells. Conclusions:, The differential expression of NCRs and a2V-ATPase in NK cell subsets of women with RSA and IVF-ET failures may have an effect in cytotoxicity and cytokine production. Additional studies are currently in effect to evaluate these activities. We suggest that the analysis of NCRs and a2V-ATPase expression in peripheral blood NK cell subsets may contribute to a better understanding in the biology of NK cells in women with RSA or IVF-ET failures. [source] Defective phosphorylation of interleukin-18 receptor , causes impaired natural killer cell function in systemic-onset juvenile idiopathic arthritisARTHRITIS & RHEUMATISM, Issue 9 2009Wilco de Jager Objective Systemic-onset juvenile idiopathic arthritis (JIA) is an autoimmune disease characterized by arthritis and systemic features. Its pathogenesis is still largely unknown. It is characterized immunologically by natural killer (NK) cell dysfunction and cytokine signatures that predominantly feature interleukin-1 (IL-1), IL-6, and IL-18. Since IL-18 can drive NK cell function, we examined how the high plasma levels of this cytokine are related to the documented NK cell failure in these patients. Methods The phenotype and function of NK cells from 10 healthy control subjects, 15 patients with polyarticular JIA, and 15 patients with systemic-onset JIA were characterized by staining and functional assays in vitro. IL-18 ligand binding was visualized by fluorescence microscopy. Phosphorylation of several MAP kinases and the IL-18 receptor , (IL-18R,) were visualized by Western blotting. Results IL-18 from the plasma of systemic-onset JIA patients stimulated the activation of NK cells from healthy controls and bound its cognate receptor. However, NK cells from systemic-onset JIA patients failed to up-regulate cell-mediated killing molecules, such as perforin and interferon-,, after IL-18 stimulation. Furthermore, treatment with IL-18 did not induce the phosphorylation of receptor-activated MAP kinases in NK cells. Alternate activation of NK cells by IL-12 induced NK cell cytotoxicity. We observed no additive effect of IL-18 in combination with IL-12 in systemic-onset JIA patients. Immunoprecipitation of IL-18R, showed that NK cells from systemic-onset JIA could not phosphorylate this receptor after IL-18 stimulation. Conclusion The mechanism of the impaired NK cell function in systemic-onset JIA involves a defect in IL-18R, phosphorylation. This observation has major implications for the understanding and, ultimately, the treatment of systemic-onset JIA. [source] | ||||||||||