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Sepsis is the organ dysfunction caused by infection.It is one of the most common critical diseases in clinic.Its morbidity and mortality are increasing year by year，which has seriously threatened human health.Innate immunity is the first line of defense against pathogens.Nature killer（NK）cells are important cells involved in the regulation of innate immunity in sepsis，and can play an important role on the progression of sepsis by secreting cytokines，inducing apoptosis and mediating cytotoxic effects.It has been found that the changes of NK cells in the early stage of sepsis are related to the prognosis of the disease.Therefore，further study on the role of NK cells in sepsis can provide a new idea for the clinical diagnosis and treatment of sepsis，and contribute to the early identification of sepsis and the improvement of prognosis.This review summarized the role and changes of NK cell in sepsis.
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Objective@#To explore the relationship between sialic-acid-binding immunoglobulin-like lectin 7 (Siglec-7) expressed on NK cells and hepatitis B virus-related cirrhosis.@*Methods@#Peripheral venous blood samples were collected from 23 healthy controls and 31 patients with hepatitis B virus-related cirrhosis (Child-Pugh A, n = 7; Child-Pugh B, n = 12; Child-Pugh C, n = 12). Peripheral blood mononuclear cells (PBMCs) were obtained by using Ficoll-Hypaque density gradient centrifugation and the expression of Siglec-7 and NK cells phenotype and their subpopulations were detected by flow cytometry. Comparisons between various groups were performed using t -test, one-way analysis of variance (ANOVA), and correlations between variables were analyzed using Pearson’s-correlation coefficient.@*Results@#(1) There was no significant difference in the percentage of NK cells and in their subpopulations with HBV-related cirrhosis and healthy controls. (2) Siglec-7 expression on NK cells in patients with HBV-related cirrhosis(62.44±13.45%)was significantly down-regulated than that to healthy controls(75.39±12.19%)while the frequency of Siglec-7+ NK cells were negatively correlated with Child-Pugh score. (3) Subpopulation analysis showed that Siglec-7 expression on CD56brightCD16-NK cells(66.99±15.93%)was significantly lower than CD56dimCD16+NK cells(76.54±13.9%) in HBV-related cirrhosis. However, the expression of Siglec-7 in healthy controls showed no difference in these two NK cell subsets. (4) Phenotypic analysis showed that Siglec-7+ NK cells express higher levels of activating receptor CD16, CD38, NKp46 and lower levels of inhibitory receptor CD158b. Indeed, the frequency of CD16 and CD38 on Siglec-7+ NK cells in HBV-related cirrhosis was lower than that in healthy controls.@*Conclusion@#The disease progression in patients with hepatitis B virus-related cirrhosis is associated to decreased frequencies of Siglec-7+NK cells.
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Objective:To explore the changes of number of CD4+ CD25 + foxp3 + regulatory T cells (Treg)and natural killer cells (NK)in the peripheral immune organs and tumor tissue of the murine models of lung cancer,and to clarify their effects on the development of lung cancer.Methods:The C57BL/6 mice were divided into Lewis lung carcinoma cells (LLC)injection group and normal control group.The mice in LLC injection group were injected with LLC subcutaneously in the armpit to establish the tumor models,while the mice in normal control group were injected with the same amount of saline.The number of CD4+ CD25 + T cells,CD4+ CD25 + foxp3 + Tregs in the spleen,lymph nodes and lung cancer tissues,and the number of NK cells in the spleen tissue were labeled by cell surface or intracellular antibody staining,and detected by flow cytometry.Results:The ratios of CD4+ CD25 + T cells to CD4+ T cells,foxp3+ cells to CD4+ CD25 + T cells,and the number of CD4+ CD25 + foxp3 + Treg in the spleen and lymph nodes of the mice in LLC injection group were increased significantly compared with normal control group (P <0.05 or P <0.01).Moreover,the ratios of CD4+ CD25 + T cells to CD4+ T cells and foxp3 + cells to CD4+ CD25 + T cells in the tumor tissue were significantly higher than those in the spleen and lymph nodes of the mice in LLC injection group.However,the ratio of NK cells in the spleen tissue of the mice in lung cancer group was significantly decreased compared with normal control group (P <0.05).Conclusion:The increase of ratio and the number of Treg cells and the decrease of ratio of NK cells in the main immune organs of lung cancer mice may promote the development of tumor and inhibit the immune response to cancer cells in vivo .
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Objective:To study the influence of different culture conditions on charcic and inhibition activity of nature killer cells ( NK) ,whether to join the modified K562 cells with IL-6 cytokine.Methods:According to the 5′end of the human IL-6 cDNA sequence,PCR primers designed to amplificate,express and transfect K562 cells cDNA library as a template for DNA.Genetic modified K562 cells as stimulating cells were prepared by expressing IL-6.To extract peripheral blood mononuclear cells( PBMC) from human peripheral blood.PBMC were explanted by genetic modified K562 stimulated.The expansion was initiated by CO-culture of PBMC and irradiate genetic modified K562 cell.The number of NK cell increased by directed induced generation of genetic modified K562 cell.Immunophenotypic analysis of NK cell surface markers was performed by flow cytometry (FCM).51Cr release assay was employed to measure the specific lysis skilling of NK cell target K562 cells.Results:We have constracted genetic modified K562 cells by genetic engineering.As stimulated cell added into the PBMC,an average of 760 ±18 fold expansion of CD56+CD16+CD3-cells was observed after 3 weeks of co-culture system.The NK cells population could proliferated more 91%±2% after expansion comparing with 6%± 0.4%in PBMC before expansion by FCM.The cytotoxical activity of NK cells which was induced by genetic modified K562 cell was the strongest than induced by IL-6 cytokine alone.The expanded NK cells lysed 92%±2% of K562 targets in a 5∶1 effector to target ratio.In this case,the NK cells induced by genetic modified K562 cells against tumor cells was more lethal.Conclusion:PBMC based in vitro expansion of natural killer cells was set up by genetic modified K562 cells.The cytotoxicity of NK cells was the strongest induced by genetic modified K562 cell treated.These results had important guiding significance for the the NK large number of amplification and used in clinical.
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Nature killer ( NK) cells, important innate immune cells, can respond in an antigenindependent manner as well as secrete huge amounts of cytokines, which can regulate acquired immunity. The role of NK cells in immune system attracts increasingly attention. Resent studies have shown that the regulating function of NK cells is by reacting with dendritic cells and secreting cytokines.
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Objective :To investigate the effects of ethanol precipitate(ET-Pre) and RNA of Grifola frondosa on non-specific immunity in mouse.Methods:The common biological methods were used to examine the levels of cytokines and immunocyte activity. Results: The killing activity of the NK cells, the phagocytosis function of macrophages and the levels of TNF?/IL-1 in the animals treated with ET-Pre and RNA respectively were significantly higher than those in the control.The RNA was stronger than ET-Pre in increasing killing activity of NK cells and phagocytosis function of macrophages. Conclusion:Both ET-Pre and RNA extracts of Grifola frondosa may promote immunoactivity nonspecifi-cally and inhibit tumor cells indirectly.