The invariant (i) natural killer (NK)T cells represent a unique subset of T lymphocytes which express the V alpha14 chain of the T cell receptor (TCR), that recognizes glycolipid antigens presented by the nonpolymorphic major histocompatibility complex (MHC) class I-like antigen presentation molecule CD1d, and they participate in protection against some microbial pathogens. Although iNKT cells have originally been regarded as T cells co-expressing NKR-P1B/C (NK1.1: CD 161), they do not seem to consistently express this marker, since NK1.1 surface expression on iNKT cells undergoes dramatic changes following facultative intracellular bacterial infection, which is correlated with functional changes of this cell population. Accumulating evidence suggests that NK1.1 allows recognition of "missing-self", thus controling activation/inhibition of NK1.1-expressing cells. Therefore, it is tempting to suggest that iNKT cells participate in the regulation of host immune responses during facultative intracellular bacterial infection by controlling NK1.1 surface expression. These findings shed light not only on the unique role of iNKT cells in microbial infection, but also provide evidence for new aspects of the NK1.1 as a regulatory molecule on these cells.
Animals ; Humans ; Listeria Infections/*immunology ; Listeria monocytogenes/*immunology ; Natural Killer T-Cells/*immunology/*microbiology

Natural killer T cells are innate-like and tissue-resident lymphocytes, which recognize lipid antigens and are enriched in the liver. Natural killer T cells play important roles in infections, tumors, autoimmune diseases, and metabolic diseases. In this study, we summarize recent findings on biology of natural killer T cells and their roles in hepatitis B virus and hepatitis C virus infection, autoimmune liver diseases, alcoholic liver disease, nonalcoholic fatty liver disease, and hepatocellular carcinoma. Controversial results from previous studies are discussed, and indicate the dynamic alteration in the role of natural killer T cells during the progression of liver diseases, which might be caused by changes in natural killer T subsets, factors skewing cytokine responses, and intercellular crosstalk between natural killer T cells and CD1d-expressing cells or bystander cells.
Animals ; Autoimmune Diseases ; immunology ; Humans ; Liver ; pathology ; Liver Diseases ; immunology ; Natural Killer T-Cells ; immunology

Mesenchymal stem cells (MSCs) can inhibit T cell proliferation, the effects of MSCs on various T cell subsets have showed different immune regulatory reactions, and their mechanisms mainly include cell-cell contact and mediation by cytokines secreted from MSCs. Encouragingly, recent studies have showed that the effects of MSCs on T-cell response to pathogens is not significant, but can obviously suppress T cell response to allogeneic antigens. In addition, MSCs can regulate the proliferation, survival, antibody secretion and differentiation of B cells, inhibit the production, proliferation, migration and antigen-presentation of DCs, and modulate the differentiation and maturation of DCs, and regulate the proliferation, cell toxicity and cytokine secretion of NK cells. In this review, the research advances on immunomodulatory effects of MSCs on various immune cells including T-lymphocytes, B-lymphocytes, NK cells and DCs are summarized with emphasis on the immunoregulatory effects of MSCs on T-lymphocytes.
B-Lymphocytes ; immunology ; Dendritic Cells ; immunology ; Humans ; Killer Cells, Natural ; immunology ; Mesenchymal Stromal Cells ; cytology ; immunology ; T-Lymphocytes ; immunology

OBJECTIVETo investigate the characteristic of NK cells and NKT cells in HBV infected pediatric subjects for evaluation of their clinical implication.

METHODSFresh peripheral blood samples were obtained from 42 HBV-infected pediatric cases and 15 healthy counterparts. NK cells and NKT cells were analyzed by flow cytometry assay. The clinical data such as serum ALT level and HBV viral load was simultaneously recorded from each HBV carrier.

RESULTSHBV-infected children had an obviously increasing percentage of NK cells 12.071% +/- 7.100%, there were significant differences between the children with chronic B hepatitis and the healthy children (P <0.05). As far as percentage of NKT 3.048% +/- 1.937% was concerned, there were not differences. Furthermore the association was not found between serum HBV viral load level and the NK lymphocyte.

CONCLUSIONOur data may provide valuable information of NK and NKT lymphocyte for evaluation of disease progression of HBV infected children NKI cells.

Adolescent ; Cells, Cultured ; Child ; Female ; Hepatitis B virus ; immunology ; physiology ; Hepatitis B, Chronic ; immunology ; virology ; Humans ; Killer Cells, Natural ; immunology ; Male ; Natural Killer T-Cells ; immunology

OBJECTIVEThis review aimed at understanding pregnancy-induced changes in the maternal immune response and mechanisms for the establishment of feto-maternal tolerance.

DATA SOURCESArticles cited in this review were obtained from PubMed in English from 2000 to 2014, and the search string included keywords such as feto-maternal tolerance, dendritic cells, macrophage, T regulatory cells, natural killer cells, cytokines and hormone.

STUDY SELECTIONArticles regarding altered maternal immune response, including the proliferation and differentiation of the altered cells, and the production of cytokines and regulation of hormones in the feto-maternal interface were retrieved, reviewed and analyzed.

RESULTSThe changes in immune cells and cytokines in the local uterine microenvironment and peripheral blood are correlated with the establishment of feto-maternal tolerance. The endocrine system regulates the maternal immune system, promoting modifications during pregnancy. In these regulatory networks, every factor is indispensible for others.

CONCLUSIONSThe integration and balance of these immune factors during pregnancy give rise to an environment that enables the fetus to escape rejection by the maternal immune system. This progress is complicated, and needs more comprehensive exploration and explanation.

Dendritic Cells ; immunology ; Female ; Humans ; Immune System ; immunology ; Immune Tolerance ; immunology ; Killer Cells, Natural ; immunology ; Pregnancy ; T-Lymphocytes, Regulatory ; immunology

This study was purposed to investigate the changes of peripheral blood T cells in children with acute leukemia at different stages and understand the immune status of children with leukemia. The CD4⁺, CD8⁺, CD4⁺/ CD8⁺ ratio, CD3⁺ and NK cells in 42 children with acute leukemia and 50 cases of normal children (as control group) were determined by flow cytometry at different periods after complete remission. The results showed that the CD3⁺ CD4⁺, CD8⁺ rate and CD4⁺/CD8⁺ ratio in newly diagnosed ALL and AML children were significantly lower than those in control group (P < 0.05). The NK cell count in newly diagnosed children with acute leukemia was significantly lower than that in control group (P < 0.05). Although the NK cell count in ALL and AML children gradually rose at 3, 6, 12 months after complete remission, but it still was statistically different from normal control group (P < 0.05). It is concluded that children with acute leukima have cellular immune disfunction at onset and during treatment, but the cell immune function gradually recovered after complete remission achieved. However, its recovery rate is slow. The results of this study can provided a basis for subsequently use of immunomodulations in leukemia children.
CD4-CD8 Ratio ; Child ; Flow Cytometry ; Humans ; Killer Cells, Natural ; Leukemia ; immunology ; T-Lymphocyte Subsets ; immunology

As a member of IL-6/IL-12 cytokine family, IL-27 is a heterodimeric cytokine composed of the p28 and EBI3. Functioning as a linkage between innate and adaptive immunity, IL-27 is mainly produced by activated antigen-presenting cells and has a variety of responder cells including T cells, NK cells, macrophages and dendritic cells. IL-27 plays an antitumor role through promoting the production of cytotoxic T cells, regulating the differentiation of T cell subsets, enhancing the function of NK cells and inhibiting the angiogenesis. On the other hand, IL-27 may also have a positive effect on tumor progress and metastasis. IL-27 can be used as a reference marker for tumor diagnosis, due to its relation to the occurrence and development of tumors. This article reviews the research progress on the roles of IL-27 in tumor biological regulation.
Dendritic Cells ; Humans ; Interleukin-27 ; immunology ; Killer Cells, Natural ; Macrophages ; Neoplasms ; immunology ; T-Lymphocyte Subsets ; T-Lymphocytes, Cytotoxic

OBJECTIVETo observe the variation and significance of natural killer T (NKT) cells in patients with severe multiple injuries.

METHODSPeripheral blood was drawn from 30 patients with severe multiple injuries and 20 healthy individuals. NKT cells and the subsets of NKT cells were stained and analyzed on fluorescence activated cell sorter (FACS) using Cellquest software. The level of IL-4 and IFN-gamma in blood serum was detected by ELISA.

RESULTSThe proportion of NKT cells was significantly increased. CD4+ NKT cells was increased (t equal to -3.11, P less than 0.01) and CD4+CD8+NKT (double negative NKT, DN NKT) cells decreased in patients with severe multiple injuries compared with healthy controls (t equal to 2.99, P less than 0.01). There was a positive correlation between the proportion of NKT cells and injury severity score (ISS) by Spearman correlation analysis (r equal to 0.70, P less than 0. 01). The level of IFN-gamma was significantly decreased and the level of IL-4 significantly increased in patients with severe multiple injuries.

CONCLUSIONSWe demonstrate that human NKT cells are increased in trauma patients. Most significantly, there is an association between ISS and NKT cells. The increased CD4+NKT cells may contribute to the reduction of Th1 cytokine production and the growth of Th2 cytokine production, leading to the suppression of immunity after injury.

Cytokines ; blood ; Humans ; Multiple Trauma ; immunology ; Natural Killer T-Cells ; immunology ; T-Lymphocyte Subsets ; immunology ; Th1 Cells ; immunology ; Th2 Cells ; immunology ; Trauma Severity Indices

T cell immunity and phagocytic activity were studied in the blood of patients with IgA nephropathy in order to clarify their roles in the pathogenesis of IgA nephropathy. The percentages of total T lymphocytes, helper T cell and suppressor T cells were significantly reduced in patients. A significantly elevated helper T cell/suppressor T cell ratio in patients showed a predominant reduction in suppressor T cells. There was a significant relationship between histologic findings and helper T cell/suppressor T cell ratio in patients. Natural Killer (NK) cell activity was significantly reduced but the lymphocyte response after phytohemagglutinin (PHA) stimulation was not in patients. ConA-induced suppressor cell activity was not depressed despite of a decrease in suppressor T cells in patients. Phagocytic activity of polymorphonuclear leucocytes (PMNs) ingesting yeasts was significantly reduced in patients. Also an inverse correlation was found between serum IgA levels and phagocytic activity of PMN. It is concluded that suppressor T cell defects, depressed phagocytic activity and impaired NK cell activity may play a role in the pathogenesis of IgA nephropathy.
B-Lymphocytes/immunology ; Glomerulonephritis, IGA/*immunology/pathology ; Humans ; Killer Cells, Natural/immunology ; Neutrophils/immunology ; *Phagocytosis ; T-Lymphocytes/*immunology ; T-Lymphocytes, Regulatory/immunology

Apoptosis ; Cell Line, Tumor ; Humans ; Immunophenotyping ; Killer Cells, Natural ; immunology ; Lymphoma, T-Cell ; immunology ; pathology ; Nose Neoplasms ; immunology ; pathology