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Killer
Kinds of Killer Terms modified by Killer Selected AbstractsDifferences in the Rapid Knockdown and Lethal Effects of Aerosol Formulations against German Cockroach (Blattaria, Blattellidae) StrainsENTOMOLOGICAL RESEARCH, Issue 4 2002Dong-Kyu LEE ABSTRACT The knockdown and lethal efficacies of five aerosol formulations including Combat Speed® (AIs: 0.1 % imiprothrin and 0.3% cyphenothrin), Raid Power® (AIs: 1.0% pyrethrin and 0.2% permethrin), Home Keeper®, (AIs: 0.2% tetramethrin and 0.3% permethrin), Super Killer® (AIs: 0.32% tetramethrin and 0.08% bioresmethrin), and Perma Kill-K® (AIs: 0.3% dichlorvos and 0.1% tetramethrin) against five strains of the German cockroach, Blattella germanica (L.) were assessed. The results show that the mean value of KT50 (5.4 sec.) of Combat Speed® was 4.5 and 3.1-folds lower than those of Perma Kill-K® and Home Keeper®, respectively. The mean value of KT90 (9.0 sec; slope = 10.02) of Combat Speed® was 3.8 to 5.8-folds lower than Perma Kill-K®, Supper Killer® and Home Keeper®. As lethal effects, the mean value of LT50 (17.3 sec.) of Combat Speed® was over 26 folds lower than Supper Killer® and Perma Kill-K®. The mean value of LT90 (32.9 sec.) of Combat Speed® was 37.4 and 15.1-folds lower than those of Supper Killer® and Perma Kill-K®, respectively. In general, Combat Speed® and Raid Power® were considered the insecticide aerosols with faster knockdown and higher lethal effects than Supper Killer®, Perma Kill-K®, and Home Keeper® against five strains of German cockroaches in Korea. Also, the knockdown and lethal effects of Supper Killer®, Perma Kill-K®, and Home Keeper® were highly variable depends on the strains. [source] Transitions in the evolution of meiosisJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2000Hurst Meiosis may have evolved gradually within the eukaryotes with the earliest forms having a one-step meiosis. It has been speculated that the putative transition from a one-step meiosis without recombination to one with recombination may have been stimulated by the invasion of Killer alleles. These imaginary selfish elements are considered to act prior to recombination. They prime for destruction (which occurs after cell division) the half of the cell on the opposite side of the meiotic spindle. Likewise the transition from one-step to two-step meiosis might have been stimulated by a subtly different sort of imaginary distorter allele, a SisterKiller. These are proposed to act after recombination. It has yet to be established that the presence of such distorter alleles could induce the transitions in question. To investigate these issues we have analysed the dynamics of a modifier (1) of recombination and (2) of the number of steps of meiosis, as they enter a population with one-step meiosis. For the modifier of recombination, we find that invasion conditions are very broad and that persistence of Killer and modifier is likely through most parameter space, even when the recombination rate is low. However, if we allow a Killer element to mutate into one that is self-tolerant, the modifier and the nonself-tolerant alleles are typically both lost from the population. The modifier of the number of steps can invade if the SisterKiller acts at meiosis II. However, a SisterKiller acting at meiosis I, far from promoting the modifier's spread, actually impedes it. In the former case the invasion is easiest if there is no recombination. The SisterKiller hypothesis therefore fails to provide a reasonable account of the evolution of two-step meiosis with recombination. As before, the evolution of self-tolerance on the part of the selfish element destroys the process. We conclude that the conditions under which SisterKillers promote the evolution of two-step meiosis are very much more limited than originally considered. We also conclude that there is no universal agreement between ESS and modifier analyses of the same transitions. [source] Defining the membrane proteome of NK cellsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2010Dhimankrishna Ghosh Abstract The present study was initiated to define the composition of the membrane proteome of the Natural Killer (NK) like cell line YTS. Isolated membranes were treated with reagents that have been reported to remove peripheral membrane proteins. Additional steps involving trifluoroethanol (TFE) were introduced in an effort to remove remaining nonintegral membrane proteins. This treatment resulted in the release of a subset of proteins without any apparent disruption of membrane integrity. The membranes were solubilized and digested with trypsin in 25% TFE. The resulting peptides were separated using an off-line two-dimensional reversed phase LC technique at alkaline and acidic pHs. Mass spectrometric analysis identified 1843 proteins with high confidence scores. On the basis of the presence of transmembrane regions or evidence of posttranslational modifications and prediction algorithms, approximately 40% of the identified proteins were predicted as plausible membrane proteins. The remaining species were largely involved in cellular processes and molecular functions that could be predicted to be transiently associated with membranes. The analytical approaches presented in this study offer robust generic methods for the identification and characterization of membrane proteins. These observations highlight the fact that the membrane is a dynamic entity that is composed of integral and stably associated proteins. Copyright © 2009 John Wiley & Sons, Ltd. [source] ORIGINAL ARTICLE: Suppression of Natural Killer Cell Cytotoxicity in Postpartum WomenAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2010Maureen Groer Citation Groer M, El-Badri N, Djeu J, Harrington M, Van Eepoel J. Suppression of natural killer cell cytotoxicity in postpartum women. Am J Reprod Immunol 2010; 63: 209,213 Problem, Natural Killer (NK) cell numbers and cytotoxicity are suppressed during pregnancy. Little is known about postpartum NK number and function. Method of study, Postpartum women (n = 39) were studied at one week and then monthly over the first six postpartum months. The standard natural killer cell cytotoxicity assay (NKCA) was performed. This is a Cr51 release assay from K562 cells cultured with peripheral blood mononuclear cells (PBMCs). Results, Data indicate suppression of NK cytotoxicity in postpartum women. Cytotoxicity at each effector:target (E:T) ratio showed a drop from 1 week postpartum, reaching a nadir at around 2 months, and a trend towards recovery of cytotoxicity from 3 to 6 months. Lytic units (LUs) from pre-incubated cells from postpartum women were lower than age-matched, non-pregnant, non-postpartum controls through the fifth postpartum month. Conclusion, These data suggest that the postpartum period, like pregnancy, is characterized by decreased NK cytotoxicity activity. This suppressed NK cytotoxic effect may result as a response to interaction with tolerized fetal microchimeric cells accumulated during pregnancy in maternal blood and tissues. [source] ORIGINAL ARTICLE: Comparative Analysis of Peripheral Natural Killer Cells in the Two Phases of the Ovarian CycleAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010Ageliki Pantazi Problem Changes in endometrial Natural Killer (NK) cells during the luteal phase of the ovarian cycle are important in initiating/maintaining a subsequent pregnancy. In the present study it was investigated whether during the menstrual cycle changes occur also in peripheral blood (PB) NKs. Method of study Blood samples during the follicular and the luteal phase were collected from 30 women without fertility problems. Samples were analyzed by flow-cytometry for: (1) NK cells (CD3,CD16+CD56+) and (2) intracellular production of interferon-, (IFN-,) by NK cells. For the comparison and correlation of the two populations between the two phases, Wilcoxon signed-rank test and Spearman's Coefficient were used. Results The differences in percentages of CD3,CD16+CD56+ cells and that of CD3,CD16+CD56+/IFN-,+ cells between the follicular and the luteal phase were not statistically significant (10.61 ± 5.11 versus 9.76 ± 4.57 and 6.48 ± 7.90 versus 7.30 ± 6.77, respectively, P > 0.05). The correlation between the two variables (NK% and NK/IFN-,%) was weakly positive (P = 0.07) only in the follicular phase. Conclusion The study did not reveal menstrual cycle-depended changes in PB NK cells. Thus, a suggestion to measure these cells in a specific phase of the cycle in order to predict the outcome of a subsequent pregnancy in women with fertility problems is objected. [source] REVIEW ARTICLE: Human NK Cells in Pregnant Uterus: Why There?AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2008Philippe Le Bouteiller Human Natural Killer (NK) cells are present in great number in pregnant uterine mucosa. They must be there for specialized functions, but which ones? This review discusses important recent observations that further contribute to this fascinating debate. Firstly, an array of corroborating findings indicates that uterine NK cell proliferation is synchronized with the cyclic surge of progesterone. Secondly, uterine NK cells are unlikely to exert a direct control on the embryo implantation. Thirdly, these NK cells influence the uterine vascular remodeling in early pregnancy but might not be the single key element that control trophoblast invasion. Finally, uterine NK cells are likely to be an important component of the local maternal immune response to pathogen infections. [source] Fas Antigen Expression on the Decidual Lymphocytes of Pre-Eclamptic PatientsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2000DOROTA DARMOCHWAL-KOLARZ PROBLEM: Apoptosis has been proposed as a mechanism for maintaining the homeostasis in the immune system. Activated lymphocytes are removed by a programmed cell death process Fas/FasL-mediated called activation induced cell death. The aim of the study was to investigate Fas antigen expression on decidual cells (T CD4+ lymphocytes, T CD8+ lymphocytes and Natural Killer (NK) cells) of pre-eclamptic patients and healthy pregnant women. METHOD OF STUDY: 12 pre-eclamptic patients and 10 healthy pregnant women were studied. Lymphocytes were isolated from decidual tissues mechanically, labeled by direct staining with monoclonal antibodies, and analyzed using the flow cytometric method. RESULTS: We found Fas antigen expression on decidual NK cells and T lymphocytes. CD 95 molecule expression and fluorescence intensity on NK cells of pre-eclamptic patients were lower when compared with controls (P<0.05). CONCLUSIONS: These findings suggest that decidual NK cells and T lymphocytes are able to undergo Fas/FasL-mediated apoptosis. It seems that NK cells' ability to undergo Fas/FasL-mediated apoptosis in pre-eclamptic patients can be altered because of lower CD95 molecule expression. [source] Potential Role of NKG2D and Its Ligands in Organ Transplantation: New Target for ImmunointerventionAMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2009B. Suárez-Álvarez NKG2D is one of the best characterized activating receptors on Natural Killer (NK) and CD8+ T cells. This receptor recognizes several different ligands (MICA/MICB and ULBPs) induced by cellular stress and infection. In addition to the role described in cancer surveillance, recent data highlight the importance of NKG2D and its ligands in organ transplantation. Allografts show evidence of MICA and MICB expression in both acute and chronic rejection. The presence of anti-MICA antibodies has been correlated with incidence of graft rejection. Furthermore, NKG2D-ligand engagement activates NK cells, which provides T-cell costimulation, and enhances antigen specific CTL-mediated cytotoxicity. Activated NK cells may function as a bridge between innate and adaptive immunity associated with transplantation. Activated NK cells in response to IL-15 can also trigger organ rejection through NKG2D and affect the maturation of both donor and recipient antigen presenting cells (APCs) and ultimately the T-cell allogeneic response. Regulatory T cells, which modulate T-cell responses in organ transplantation and infections, were reduced in numbers by NK cells exposed to intracellular pathogens, possibly via interaction with one NK2GD receptor. Blockage of NKG2D-NKG2D-L interactions provides a novel pathway for development of inhibitors. These studies have important clinical and therapeutic implications in solid organ transplantation. [source] Killers and beyond: NK-cell-mediated control of immune responsesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Christopher E. Andoniou Abstract Effective immunity requires coordinated activation of innate and adaptive immune responses. NK cells are principal mediators of innate immunity, able to respond to challenge quickly and generally without prior activation. The most acknowledged functions of NK cells are their cytotoxic potential and their ability to release large amounts of cytokines, especially IFN-,. Recently, it has become clear that NK cells are more than assassins. Indeed, NK cells play critical roles in shaping adaptive immunity. [source] Crime Beat: A Decade of Covering Cops and KillersTHE JOURNAL OF POPULAR CULTURE, Issue 4 2007Philip Booth No abstract is available for this article. [source] Illegitimate Killers: The Symbolic Ecology and Cultural Politics of Coyote-Hunting Tournaments in Addison County, VermontANTHROPOLOGY & HUMANISM, Issue 2 2009Marc A. BoglioliArticle first published online: 6 NOV 200 SUMMARY Although I have conducted ethnographic research on hunting in central Vermont since 1996, one important issue has remained conspicuously absent from my field notes: organized hunting protest. That all changed one cold February day in 2005 as protesters from a home-grown animal rights group stood along a country road in Whiting, Vermont, to voice their opposition to the first annual Howlin' Hills Coyote Hunt. This coyote-hunting tournament was characterized by a broad assortment of local residents,including hunters,as a morally corrupt departure from traditional hunting ethics and from that day forward Addison County has been caught up in a social drama that may forever change the face of hunting in Vermont. As deep philosophical differences were revealed between not only hunters and antihunters, but between hunters themselves, a small window opened for a more general moral critique of hunting. Drawing on testimony from hunters, animal rights activists, Vermont Department of Fish and Wildlife personnel, and my own experiences at coyote tournaments, I explain the perspectives of the various actors in this drama as they struggle to define the meaning and ethical place of hunting in the 21st century. [Keywords: human,animal relations, symbolic ecology, hunting, rural America, coyotes] [source] Dr Harold Frederick Shipman: An enigmaCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 3 2010John Gunn Dr. Shipman was the worst known serial killer in British history, at least in terms of numbers of victims, and possibly the worst in world history, if politicians are excluded. He killed at least 215 patients and may have begun his murderous career at the age of 25, within a year of finishing his medical training. His case has had a profound impact on the practice of medicine in the United Kingdom. Was he a special case? What were the origins of this behaviour? Could the behaviour have been prevented? It is necessary to learn what we can from a few personal facts and largely circumstantial evidence. He withheld himself from any useful clinical investigation or treatment once he had been taken into custody. Could he have been treated at any stage? Copyright © 2010 John Wiley & Sons, Ltd. [source] A role for innate immunity in type 1 diabetes?DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 2 2003H. Beyan Abstract Two arms of the immune system, innate and adaptive immunity, differ in their mode of immune recognition. The innate immune system recognizes a few highly conserved structures on a broad range of microorganisms. On the other hand, recognition of self or autoreactivity is generally confined to the adaptive immune response. Whilst autoimmune features are relatively common, they should be distinguished from autoimmune disease that is infrequent. Type 1 diabetes is an immune-mediated disease due to the destruction of insulin secreting cells mediated by aggressive immune responses, including activation of the adaptive immune system following genetic and environmental interaction. Hypotheses for the cause of the immune dysfunction leading to type 1 diabetes include self-reactive T-cell clones that (1) escape deletion in the thymus, (2) escape from peripheral tolerance or (3) escape from homeostatic control with an alteration in the immune balance leading to autoimmunity. Evidence, outlined in this review, raises the possibility that changes in the innate immune system could lead to autoimmunity, by either priming or promoting aggressive adaptive immune responses. Hostile microorganisms are identified by genetically determined surface receptors on innate effector cells, thereby promoting clearance of these invaders. These innate effectors include a few relatively inflexible cell populations such as monocytes/macrophages, dendritic cells (DC), natural killer (NK) cells, natural killer T (NKT) cells and ,, T cells. Recent studies have identified abnormalities in some of these cells both in patients with type 1 diabetes and in those at risk of the disease. However, it remains unclear whether these abnormalities in innate effector cells predispose to autoimmune disease. If they were to do so, then modulation of the innate immune system could be of therapeutic value in preventing immune-mediated diseases such as type 1 diabetes. Copyright © 2002 John Wiley & Sons, Ltd. [source] Persistent inhibition of human natural killer cell function by ziram and pentachlorophenolENVIRONMENTAL TOXICOLOGY, Issue 4 2005Thyneice R. Taylor Abstract Ziram is a currently used agricultural fungicide. It is also used as an additive in the production of latex gloves. Because of these uses, there is a potential for human exposure to this compound. Pentachlorophenol (PCP) has been used as an insecticide, fungicide, disinfectant, and ingredient in antifouling paints. Currently, it is used as a wood preservative for power-line poles and fence posts. Measurable levels of PCP have been detected in human blood and urine. In previous studies we demonstrated that both these compounds could cause very significant inhibition of the tumor-killing function of human natural killer (NK) cells. NK lymphocytes play a central role in immune defense against viral infection and the formation of primary tumors. So interference with their function could increase the risk of tumor development. In the present study we examined the effects of exposure to ziram or PCP of brief duration (1 h) on the ability of NK cells to destroy tumor cells. NK cells were exposed to either ziram (5,0.5 ,M) or PCP (10,5 ,M) for 1 h followed by 0 h, 24 h, 48 h, or 6 days in compound-free media and then were tested for the ability to lyse as well as to bind tumor cells. A 1-h exposure to as little as 2.5 ,M ziram decreased the ability of NK cells to lyse target tumor cells, which persisted up to 6 days following exposure. The loss of lytic function for from 24 h to 6 days following exposure was accompanied by a comparable loss of NK capacity to bind tumor cells. Exposure to 10 ,M PCP for 1 h caused a progressive loss (greater than 80%) of lytic function within 6 days of exposure. In contrast to ziram, PCP exposure caused no accompanying loss of binding function. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 418,424, 2005. [source] Natural killer cells in viral hepatitis: facts and controversiesEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2010Mario U. Mondelli Eur J Clin Invest 2010; 40 (9): 851,863 Abstract Background, Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major human hepatotropic pathogens responsible for a large number of chronic infections worldwide. Their persistence is thought to result from inefficiencies of innate and adaptive immune responses; however, very little information is available on the former. Natural killer (NK) cells are a major component of innate immunity and their activity is tightly regulated by several inhibitory and activating receptors. Design, In this review, we examine controversial findings regarding the role of NK cells in the pathogenesis of acute and chronic liver disease caused by HCV and HBV. Results, Recent studies built up on technical advances to identify NK receptors and their functional correlates in this setting. While NK cells seem to behave correctly during acute hepatitis, it would appear that the NK cytotoxic potential is generally conserved in chronic hepatitis, if not increased in the case of HCV. In contrast, their ability to secrete antiviral cytokines such as interferon ex vivo or after cytokine stimulation is severely impaired. Conclusions, Current evidence suggests the existence of an NK cell functional dichotomy, which may contribute to virus persistence, while maintaining low-level chronic liver inflammation. The study of liver-infiltrating NK cells is still at the very beginning, but it is likely that it will shed more light on the role of this simple and at the same time complex innate immune cell in liver disease. [source] Age-matched lymphocyte subpopulation reference values in childhood and adolescence: application of exponential regression analysisEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2008Sabine Huenecke Abstract Background:, Normal values of lymphocyte subpopulations for healthy children and adults have been published in defined age groups exclusively, which results in difficult data interpretation for patients close to the limit of contiguous age group ranges. In addition, normal values for a number of lymphocyte subpopulations have not been established to date. Objective:, The aim of this study was to develop a model which provides continuous age-dependent reference values. This model was applied for lymphocyte subpopulations such as naïve and memory T cells as well as their activation profile with diagnostic relevance in children and adults. Study design:, A total of 100 blood samples, obtained from 80 healthy children and 20 adults were analysed by means of four colour-flow cytometry. Continuous age-dependent reference values were computed based on the residual values in an exponential regression model. Results:, We calculated a continuous age-related regression model for both, absolute cell counts and percentages of CD3+CD4+ T helper (TH) cells, CD3+CD8+ cytotoxic T cells, CD56+CD3, natural killer (NK) cells, CD56+CD3+ T cells, CD3+CD4+CD45RA+ naïve TH cells, CD3+CD4+CD45RO+ memory TH cells, CD3+CD8+CD45RA+CD28+ naïve cytotoxic T cells, CD3+CD8+CD45RO+ memory cytotoxic T cells, CD3+CD8+CD69+ early activated cytotoxic T cells and CD3+CD8+HLA-DR+ late activated cytotoxic T cells, respectively, to obtain reference values. Conclusion:, Based on an exponential regression model, the obtained reference values reflect the continuous maturation of lymphocyte subsets during childhood. [source] Typing of the immunological system in human embryos by coelocentesisEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2007Maria Concetta Renda Abstract Coelocentesis offers a new opportunity for gaining access to the human embryos from 28 d postfertilization. However, while some studies about its biochemical composition have been reported, our knowledge about immunological pattern of this compartment is still limited. For this reason, we studied the human coelomic fluids sampled from 6.6 to 10 wk of gestation. The majority of cellular population consisted in mesenchymal/epithelial cells. In fluids sampled before 10 wk we found only a preT Cell Receptor expression and an absence or a very low frequency of B lymphocytes, T lymphocytes and NK (natural killer) antigens. These preliminary data suggest that the immunological system in human embryos could be in the ideal conditions to start a process of tolerance induction. [source] Study of cord blood natural killer cell suppressor activityEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2001S. El Marsafy Abstract: We tested the immunosuppressive effect of cord blood (CB) natural killer (NK) cells using highly purified CB NK cells in mixed lymphocyte cultures (MLC) containing autologous CB T cells as responders. Control cultures were done without NK cells. Our findings revealed that CB NK cells induced a dose-dependent inhibition of T lymphocyte proliferation as evidenced by decreased 3H-thymidine incorporation in MLC. The T cell alloproliferation was significantly decreased in the presence of an NK cell to responder cell ratio of 0.1, 0.2 or 0.4 compared with control cultures done without NK cells (p=0.02, 0.003 and 0.0002, respectively). T lymphocyte inhibition was also achieved using irradiated CB NK cells and still demonstrable on addition of disparate CB NK and T cells to the MLC. In agreement with previous reports, adult blood NK cells inhibited the alloreactive T cells in the MLC using adult T lymphocytes as responders. Compared to control cultures done without NK cells, statistically significant inhibition of 3H-thymidine incorporation in MLC was observed at a ratio of NK cells to responder cells ratio of 0.2 or 0.4 (p=0.02). To investigate the mechanism whereby CB NK cells can interfere with the development of alloreactive T cells in MLC, we measured the tumour necrosis factor-, (TNF-,) concentrations in MLC supernatants using NK cell-depleted or unseparated CB mononuclear cells (MNC) as responders. The results revealed significantly high levels of TNF-, in the absence of NK cells (p=0.007). We conclude that CB NK cells suppress alloreactive T lymphocytes as do their counterparts in adult blood. However, the high NK to T cell ratio in CB could contribute to a more marked suppressive potential compared to that in adult blood. The mechanism of NK-mediated inhibition is likely related to disruption of the TNF-, pathway of T-lymphocyte activation. [source] Manipulation of NK cytotoxicity by the IAP family member LivinEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2007Boaz Nachmias Abstract Natural killer (NK) cells are part of the innate immune system, capable of killing tumor and virally infected cells. NK cells induce apoptosis in the target cell by either granule- or receptor-mediated pathways. A set of inhibitory and activation ligands governs NK cell activation. As transformed cells often attempt to evade NK cell killing, up-regulation of a potential anti-apoptotic factor should provide a survival advantage. The inhibitor of apoptosis protein (IAP) family can inhibit apoptosis induced by a variety of stimuli. We have previously described a new IAP family member, termed Livin, which has two splice variants (, and ,) with differential anti-apoptotic activities. In this study, we explore the ability of Livin to inhibit NK cell-induced killing. We demonstrate that Livin,, moderately protects against NK cell killing whereas Livin,, augments killing. We show that Livin,, inhibition in Jurkat cells is apparent upon concomitant activation of an inhibitory signal, suggesting that Livin augments an extrinsic inhibitory signal rather than functioning as an independent inhibitory mechanism. Finally, we demonstrate that detection of both Livin isoforms in melanoma cells correlates with a low killing rate. To date, this is the first evidence that directly demonstrates the ability of IAP to protect against NK cell-induced apoptosis. [source] Biological function of the soluble CEACAM1 protein and implications in TAP2-deficient patientsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2004Gal Markel Abstract Interactions of natural killer (NK) cells with MHC class I proteins provide the main inhibitory signals controlling NK killing activity. It is therefore surprising to learn that TAP2-deficientpatients suffer from autoimmune manifestations only occasionally in later stages of life. We have previously described that the CEACAM1-mediated inhibitory mechanism of NK cytotoxicity plays a major role in controlling NK autoreactivity in three newly identified TAP2-deficient siblings. This novel mechanism probably compensates for the lack of MHC class I-mediated inhibition. The CEACAM1 protein can also be present in a soluble form and the biological function of the soluble form of CEACAM1 with regard to NK cells has not been investigated. Here we show that the homophilic CEACAM1 interactions are abrogated in the presence of soluble CEACAM1 protein in a dose-dependent manner. Importantly, the amounts of soluble CEACAM1 protein detected in sera derived from the TAP2-deficient patients were dramatically reduced as compared to healthy controls. This dramatic reduction does not depend on the membrane-bound metalloproteinase activity. Thus, the expression of CEACAM1 and the absence of soluble CEACAM1 observed in the TAP2-deficient patients practically maximize the inhibitory effect and probably help to minimize autoimmunity in these patients. [source] Natural killer cell proliferation and circulating cytokines in patients with bilateral basal ganglia calcificationEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2002T. Morishima Ten adult patients with symmetrical calcifications in the bilateral basal ganglia (diagnosed as physiological calcifications) were analyzed for lymphocyte subsets and cytokines. Increased number of natural killer (NK) cells were identified in the peripheral blood of seven patients by lymphocyte subset analysis. Tumor necrosis factor- , was detected in the sera of five patients and interferon- , was detected in one patient. In summary, NK cell propagation and circulating cytokines, particularly tumor necrosis factor- ,, may be involved in the etiology of basal ganglia calcification. [source] Anti-tumor activity of mesenchymal stem cells producing IL-12 in a mouse melanoma modelEXPERIMENTAL DERMATOLOGY, Issue 11 2006Lina Elzaouk Abstract:, Mesenchymal stem cells (MSCs) represent a new tool for delivery of therapeutic agents to tumor cells. In this study, we have evaluated the anti-tumor activity of human MSCs stably transduced with a retroviral vector expressing the cytokine interleukin-12 (IL-12) in a mouse melanoma model. Application of MSC(IL-12) but not control MSCs strongly reduced the formation of lung metastases of B16F10 melanoma cells. The activity of the MSC(IL-12) cells was dependent on the presence of natural killer (NK) cells in this experimental setting. Further, MSC(IL-12) cells elicited a pronounced retardation of tumor growth and led to prolonged survival when injected into established subcutaneous melanoma in a therapeutic regimen. The therapeutic effect of the MSC(IL-12) was in part mediated by CD8+ T cells, while NK cells and CD4+ T cells appeared to play a minor role. The anti-tumor effect of MSC(IL-12) cells was of similar efficiency as observed for application of naked plasmid DNA encoding IL-12. The presented data demonstrate that these two different strategies can induce a similar therapeutic anti-tumor efficacy in the mouse melanoma tumor model. [source] Suppression of splenic macrophage Candida albicans phagocytosis following in vivo depletion of natural killer cells in immunocompetent BALB/c mice and T-cell-deficient nude miceFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2002I Algarra Abstract The resistance of mice to systemic infections caused by Candida albicans is associated with activated splenic macrophages. In addition, there is a correlation between natural killer (NK) cell activation and the resistance to systemic candidiasis. The present study was designed to clarify the role of NK cells in the control of splenic macrophage C. albicans phagocytosis by either depleting NK cells (anti-asialo GM1 treatment) or maintaining them in an activated state (tilorone treatment) in both immunocompetent BALB/c mice and T-cell-deficient nude mice. The results of the in vitro phagocytosis assays were analyzed by flow cytometry and demonstrate the pivotal role of NK cells in controlling the capacity of splenic macrophages to phagocytose C. albicans. In summary, these data provide evidence that the NK cells are the main inducers of phagocytic activity of splenic macrophages and that they mediate the protection against C. albicans systemic infection. [source] Clinical relevance of three subtypes of primary sinonasal lymphoma characterized by immunophenotypic analysisHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2004Gwi Eon Kim MD Abstract Background. The purpose of this study was to investigate the clinical relevance of subtypes categorized by immunophenotypic analysis in primary sinonasal lymphomas. Methods. Eighty patients with localized non-Hodgkin's lymphoma involving the nasal cavity and/or paranasal sinuses were divided into three subtypes on the basis of their immunohistochemical findings: (A) B-cell lymphoma (n = 19), (B) T-cell lymphoma (n = 27), and (C) natural killer (NK)/T-cell lymphoma (n = 34). The clinicopathologic profiles, immunophenotypic data, patterns of treatment failure, and survival data among the three patient groups were retrospectively compared. Results. The nasal cavity was the predominant site of involvement in T-cell and NK/T-cell lymphoma, whereas sinus involvement without nasal disease was common in B-cell lymphoma. Systemic B symptoms were frequently observed in NK/T-cell lymphoma. Almost all patients with NK/T-cell lymphoma showed a strong association with the Epstein-Barr virus by in situ hybridization studies. Sixty-five patients (81%) patients achieved complete remission after initial treatment, but 36 (55%) of these subsequently experienced treatment failure. Although there were no significant differences in locoregional failure rates among the patients of the three groups, distant failure was far more common in B-cell or NK/T-cell lymphoma than in T-cell lymphoma (p = .005). Most B-cell lymphoma cases showed a predilection for sites of systemic failure in the nodal and extranodal sites below the diaphragm, such as the paraaortic lymph nodes or the gastrointestinal (GI) tract, whereas patients with NK/T-cell lymphoma showed an increased risk of systemic dissemination to the skin, testes, or GI tract, including the development of hemophagocytic syndrome. The 5-year actuarial and disease-free survival rates for all patients were 57% and 51%, respectively. Of the three subtypes of primary sinonasal lymphomas, T-cell lymphoma seemed to carry the most favorable prognosis and NK/T-cell lymphoma the worst. (The 5-year actuarial survival rate was 57% for B-cell lymphoma, 80% for T-cell lymphoma, 37% for NK/T-cell lymphoma; p = .02, log-rank.) By univariate and multivariate analyses, immunophenotype was identified as the most important prognostic factor. Conclusions. Our data indicate that the three subtypes of primary sinonasal lymphomas classified by immunohistochemical studies exhibit different clinical profiles, different patterns of failure, and different treatment outcomes. Given these observations, it is concluded that the recognition of these distinct subsets, diagnosed on the basis of immunophenotypic study, is very important and clinically relevant in predicting their potential behavior and prognosis. © 2004 Wiley Periodicals, Inc. Head Neck26: 584,593, 2004 [source] Functional alterations of liver innate immunity of mice with aging in response to CpG-oligodeoxynucleotide,HEPATOLOGY, Issue 5 2008Toshinobu Kawabata Immune functions of liver natural killer T (NKT) cells induced by the synthetic ligand ,-galactosylceramide enhanced age-dependently; hepatic injury and multiorgan dysfunction syndrome (MODS) induced by ligand-activated NKT cells were also enhanced. This study investigated how aging affects liver innate immunity after common bacteria DNA stimulation. Young (6 weeks) and old (50-60 weeks) C57BL/6 mice were injected with CpG oligodeoxynucleotides (CpG-ODN), and the functions of liver leukocytes were assessed. A CpG-ODN injection into the old mice remarkably increased tumor necrosis factor (TNF) production in Kupffer cells, and MODS and lethal shock were induced, both of which are rarely seen in young mice. Old Kupffer cells showed increased Toll-like receptor-9 expression, and CpG-ODN challenge augmented TNF receptor and Fas-L expression in liver NKT cells. Experiments using mice depleted of natural killer (NK) cells by anti-asialoGM1 antibody (Ab), perforin knockout mice, and mice pretreated with neutralizing interferon (IFN)-, Ab demonstrated the important role of liver NK cells in antitumor immunity. The production capacities of old mice for IFN-,, IFN-,, and perforin were much lower than those of young mice, and the CpG-induced antitumor cytotoxicity of liver NK cells lessened. Lethal shock and MODS greatly decreased in old mice depleted/deficient in TNF, FasL, or NKT cells. However, depletion of NK cells also decreased serum TNF levels and FasL expression of NKT cells, which resulted in improved hepatic injury and survival, suggesting that NK cells are indirectly involved in MODS/lethal shock induced by NKT cells. Neutralization of TNF did not reduce the CpG-induced antitumor effect in the liver. Conclusion: Hepatic injury and MODS mediated by NKT cells via the TNF and FasL-mediated pathway after CpG injection increased, but the antitumor activity of liver NK cells decreased with aging. (HEPATOLOGY 2008.) [source] Activation of hepatic stellate cells after phagocytosis of lymphocytes: A novel pathway of fibrogenesis,HEPATOLOGY, Issue 3 2008Nidal Muhanna Increased CD8-T lymphocytes and reduced natural killer (NK) cells contribute to hepatic fibrosis. We have characterized pathways regulating the interactions of human hepatic stellate cells (HSCs) with specific lymphocyte subsets in vivo and in vitro. Fluorescence-activated cell sorting (FACS) was used to characterize human peripheral blood lymphocytes (PBLs) and intrahepatic lymphocytes (IHLs) obtained from healthy controls and from patients with either hepatitis B virus (HBV) or hepatitis C virus (HCV) with advanced fibrosis. Liver sections were analyzed by immunohistochemistry and confocal microscopy. To investigate in vitro interactions, PBLs from healthy controls or patients with HCV cirrhosis were co-cultured with an immortalized human HSC line (LX2 cells) or with primary HSCs. Significant alterations in lymphocyte distribution were identified in IHLs but not PBLs. The hepatic CD4/CD8 ratio and NK cells were significantly reduced in HBV/HCV patients. Expression of alpha-smooth muscle actin and infiltration of CD4, CD8, and NK cells were readily apparent in liver sections from patients with cirrhosis but not in healthy controls. Lymphocytes from each subset were in proximity to HSCs primarily within the periportal regions, and some were directly attached or engulfed. In culture, HSC activation was stimulated by HCV-derived CD8-subsets but attenuated by NK cells. Confocal microscopy identified lymphocyte phagocytosis within HSCs that was completely prevented by blocking intracellular adhesion molecule 1 (ICAM-1) and integrin molecules, or by irradiation of HSCs. LX2 knockdown of either Cdc42 or Rac1 [members of the Rho-guanosine triphosphatase (GTPase) family] prevented both phagocytosis and the activation of HSC by HCV-derived lymphocytes. Conclusion: The CD4/CD8 ratio and NK cells are significantly decreased in livers with advanced human fibrosis. Moreover, disease-associated but not healthy lymphocytes are engulfed by cultured HSCs, which is mediated by the Rac1 and Cdc42 pathways. Ingestion of lymphocytes by HSCs in hepatic fibrosis is a novel and potentially important pathway regulating the impact of lymphocytes on the course of hepatic fibrosis. (HEPATOLOGY 2008.) [source] Hepatitis C virus,infected hepatocytes extrinsically modulate dendritic cell maturation to activate T cells and natural killer cells,HEPATOLOGY, Issue 1 2008Takashi Ebihara Dendritic cell maturation critically modulates antiviral immune responses, and facilitates viral clearance. Hepatitis C virus (HCV) is characterized by its high predisposition to persistent infection. Here, we examined the immune response of human monocyte-derived dendritic cells (MoDCs) to the JFH1 strain of HCV, which can efficiently replicate in cell culture. However, neither HCV RNA replication nor antigen production was detected in MoDCs inoculated with JFH1. None of the indicators of HCV interacting with MoDCs we evaluated were affected, including expression of maturation markers (CD80, 83, 86), cytokines (interleukin-6 and interferon-beta), the mixed lymphocyte reaction, and natural killer (NK) cell cytotoxicity. Strikingly, MoDCs matured by phagocytosing extrinsically-infected vesicles containing HCV-derived double-stranded RNA (dsRNA). When MoDCs were cocultured with HCV-infected apoptotic Huh7.5.1 hepatic cells, there was increased CD86 expression and interleukin-6 and interferon-beta production in MoDCs, which were characterized by the potential to activate NK cells and induce CD4+ T cells into the T helper 1 type. Lipid raft-dependent phagocytosis of HCV-infected apoptotic vesicles containing dsRNA was indispensable to MoDC maturation. Colocalization of dsRNA with Toll-like receptor 3 (TLR3) in phagosomes suggested the importance of TLR3 signaling in the MoDC response against HCV. Conclusion: The JFH1 strain does not directly stimulate MoDCs to activate T cells and NK cells, but phagocytosing HCV-infected apoptotic cells and their interaction with the TLR3 pathway in MoDCs plays a critical role in MoDC maturation and reciprocal activation of T and NK cells. (HEPATOLOGY 2008.) [source] Impaired liver regeneration and increased oval cell numbers following T cell,mediated hepatitis,HEPATOLOGY, Issue 1 2007Ian N. Hines The regeneration of liver tissue following transplantation is often complicated by inflammation and tissue damage induced by a number of factors, including ischemia and reperfusion injury and immune reactions to the donor tissue. The purpose of the current study is to characterize the effects of T cell,mediated hepatitis induced by concanavalin A (ConA) on the regenerative response in vivo. Liver regeneration following a partial (70%) hepatectomy (pHx) was associated with elevations in serum enzymes and the induction of key cell cycle proteins (cyclin D, cyclin E, and Stat3) and hepatocyte proliferation. The induction of T cell,mediated hepatitis 4 days before pHx increased serum enzymes 48 hours after pHx, reduced early cyclin D expression and Stat3 activation, and suppressed hepatocyte proliferation. This inhibition of proliferation was also associated with increased expression of p21, the activation of Smad2, the induction of transforming growth factor beta and interferon gamma expression, and reduced hepatic interleukin 6 production. Moreover, the ConA pretreatment increased the numbers of separate oval cell-like CD117+ cells and hematopoietic-like Sca-1+ cell populations 48 hours following pHx. The depletion of natural killer (NK) cells, an important component of the innate immune response, did not affect liver injury or ConA-induced impairment of hepatocyte proliferation but did increase the numbers of both CD117-positive and Sca-1,positive cell populations. Finally, splenocytes isolated from ConA-pretreated mice exerted cytotoxicity toward autologous bone marrow cells in an NK cell,dependent manner. Conclusion: T cell,mediated hepatitis alters early cytokine responses, reduces hepatocellular regeneration, and induces NK cell,sensitive oval cell and hematopoietic-like cell expansion following pHx. (HEPATOLOGY 2007;46:229,241.) [source] Constitutive androstane receptor (CAR) ligand, TCPOBOP, attenuates Fas-induced murine liver injury by altering Bcl-2 proteins,HEPATOLOGY, Issue 1 2006Edwina S. Baskin-Bey The constitutive androstane receptor (CAR) modulates xeno- and endobiotic hepatotoxicity by regulating detoxification pathways. Whether activation of CAR may also protect against liver injury by directly blocking apoptosis is unknown. To address this question, CAR wild-type (CAR+/+) and CAR knockout (CAR,/,) mice were treated with the CAR agonist 1,4-bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) and then with the Fas agonist Jo2 or with concanavalin A (ConA). Following the administration of Jo2, hepatocyte apoptosis, liver injury, and animal fatalities were abated in TCPOBOP-treated CAR+/+ but not in CAR,/, mice. Likewise, acute and chronic ConA-mediated liver injury and fibrosis were also reduced in wild-type versus CAR,/, TCPOBOP-treated mice. The proapoptotic proteins Bak (Bcl-2 antagonistic killer) and Bax (Bcl-2-associated X protein) were depleted in livers from TCPOBOP-treated CAR+/+ mice. In contrast, mRNA expression of the antiapoptotic effector myeloid cell leukemia factor-1 (Mcl-1) was increased fourfold. Mcl-1 promoter activity was increased by transfection with CAR and administration of TCPOBOP in hepatoma cells, consistent with a direct CAR effect on Mcl-1 transcription. Indeed, site-directed mutagenesis of a putative CAR consensus binding sequence on the Mcl-1 promoter decreased Mcl-1 promoter activity. Mcl-1 transgenic animals demonstrated little to no acute liver injury after administration of Jo2, signifying Mcl-1 cytoprotection. In conclusion, these observations support a prominent role for CAR cytoprotection against Fas-mediated hepatocyte injury via a mechanism involving upregulation of Mcl-1 and, likely, downregulation of Bax and Bak. (HEPATOLOGY 2006;44:252,262.) [source] Neutrophil depletion protects against murine acetaminophen hepatotoxicity,,HEPATOLOGY, Issue 6 2006Zhang-Xu Liu We previously reported that liver natural killer (NK) and NKT cells play a critical role in mouse model of acetaminophen (APAP)-induced liver injury by producing interferon gamma (IFN-,) and modulating chemokine production and subsequent recruitment of neutrophils into the liver. In this report, we examined the role of neutrophils in the progression of APAP hepatotoxicity. C57BL/6 mice were given an intraperitoneal toxic dose of APAP (500 mg/kg), which caused severe acute liver injury characterized by significant elevation of serum ALT, centrilobular hepatic necrosis, and increased hepatic inflammatory cell accumulation. Flow cytometric analysis of isolated hepatic leukocytes demonstrated that the major fraction of increased hepatic leukocytes at 6 and 24 hours after APAP was neutrophils (Mac-1+Gr-1+). Depletion of neutrophils by in vivo treatment with anti-Gr-1 antibody (RB6-8C5) significantly protected mice against APAP-induced liver injury, as evidenced by markedly reduced serum ALT levels, centrilobular hepatic necrosis, and improved mouse survival. The protection was associated with decreased FasL-expressing cells, cytotoxicity against hepatocytes, and respiratory burst in hepatic leukocytes. In intracellular adhesion molecule (ICAM)-1,deficient mice, APAP caused markedly reduced liver injury when compared with wild-type mice. The marked protection in ICAM-1,deficient mice was associated with decreased accumulation of neutrophils in the liver. Hepatic GSH depletion and APAP-adducts showed no differences among the antibody-treated, ICAM-1,deficient, and normal mice. In conclusion, accumulated neutrophils in the liver contribute to the progression and severity of APAP-induced liver injury. (HEPATOLOGY 2006;43:1220,1230.) [source] | ||||||||||||||||||||||||||||||||||||||||||||||