NK22 Cells Research Articles

Expression of retinoid-related orphan receptor γt (RORγt) of decidual NK22 cells in women with spontaneous miscarriages with or without chromosomal abnormality

Expression of retinoid-related orphan receptor γt (RORγt) of decidual NK22 cells in women with spontaneous miscarriages with or without chromosomal abnormality

Expression of retinoid-related orphan receptor (ROR)γt on NK22 cells in the peripheral blood and uterine endometrium of women with unexplained recurrent pregnancy loss and unexplained infertility.

Recently, NK22 cells, a subset of interleukin (IL)-22-producing natural killer (NK) cells, were identified. We have previously reported the higher percentage of NK22 cells in women suffering recurrent pregnancy loss (RPL). Moreover, we have also reported lower expression of NKp46, a kind of natural cytotoxicity receptor (NCR), on NK cells and the changes of NK cell producing cytokines in women who experience RPL. NK22 cells express NCRs, such as NKp44 or NKp46. Retinoid-related orphan receptor γt (RORγt) is known as a regulator of NK22 cells; however, in NK22 cells of peripheral blood (PB) and the uterine endometrium (UE), the relationship between NCRs and RORγt is unclear. We investigate RORγt expression NK22 cells in the PB and UE of women with unexplained infertility (uI) or unexplained RPL (uRPL). Lymphocytes were extracted from PB and UE, derived from women with uI or uRPL. Expression of RORγt and NCRs in NK cells and NK cell-produced cytokines were analyzed by flow cytometry. CD56+ /NKp46+ /RORγt+ cells were positively correlated with CD56+ /IL-22+ cells in both PB and UE. CD56bright /NKp46bright /RORγt+ cells were significantly higher in uRPL than in uI, and endometrial CD56bright /NKp46bright /RORγt+ cells were positively correlated with PB. In UE, CD56bright /RORγt+ cells were negatively correlated with CD56bright /interferon-γ+ and CD56bright /tumor necrosis factor-α+ cells of uRPL. RORγt may be associated with NK22 cells in reproduction. Particularly, higher expression of RORγt may be associated with elevated NK22 cells in uRPL.

The role of retinoid-related orphan receptor γt (RORγt) for peripheral blood or endometrial NK22 cells in the women with unexplained recurrent pregnancy loss or unexplained infertility

The role of retinoid-related orphan receptor γt (RORγt) for peripheral blood or endometrial NK22 cells in the women with unexplained recurrent pregnancy loss or unexplained infertility

RORγt+ IL-22-producing NKp46+ cells protect from hepatic ischemia reperfusion injury in mice

NKp46(+) cells are major effector cells in the pathogenesis of hepatic ischemia reperfusion injury (IRI). Nevertheless, the precise role of unconventional subsets like the IL-22-producing NKp46(+) cells (NK22) remains unknown. The purpose of this study was to examine the role of NK22 cells in IRI in transplantation, particularly with respect to regulation by the transcription factor ROR-gamma-t (RORγt). To explore the role of NK22 cells in IRI in the absence of adaptive immunity, B6.RORγt-(gfp/wt)-reporter and B6.RORγt-(gfp/gfp)-knockout (KO) mice on a Rag KO background underwent 90min partial warm ischemia, followed by 24h of reperfusion. Rag KO mice that possess fully functional NKp46(+) cells, and Rag-common-γ-chain-double-KO (Rag-γc-DKO) mice that lack T, B and NKp46(+) cells, were used as controls. We found that Rag-γc-DKO mice lacking NK22 cells show more severe levels of hepatocellular damage (GPT, histological injury) when compared to both Rag-RORγt-reporter and Rag KO mice that possess NK22 cells. Importantly, Rag-RORγt-reporter and Rag KO mice undergoing IRI expressed high protein levels of both IL-22 and GFP (RORγt), suggesting a protective role for RORγt(+) NK22 cells in IRI. Therefore, we tested the hypothesis that RORγt critically protects from IRI through the induction of hepatic NK22 cells by studying Rag-Rorγt-DKO mice under IRI conditions. We found that the lack of RORγt(+) NK22 cells in Rag-Rorγt-DKO mice significantly enhanced IR-induced hepatocellular injury, a phenotype that could be reversed upon adoptive transfer of Rag-Rorγt-reporter NK22 cells into DKO mice. RORγt(+) NK22 cells play an important protective role in IRI in mice.

NK cell abnormality and its treatment in women with reproductive failures such as recurrent pregnancy loss, implantation failures, preeclampsia, and pelvic endometriosis.

The regulation of uterine and peripheral blood natural killer (NK) cells has been associated with problems related to reproductive immunology such as recurrent pregnancy loss (RPL), implantation failure or preeclampsia. NKp46, one of the natural cytotoxicity receptors (NCRs), is a unique marker that functions in NK cell cytotoxicity and cytokine production. Expression of NKp46 on NK cells is lower in women with recurrent pregnancy loss and pregnancy-induced hypertension. Moreover, expression of NKp46 on peritoneal fluid NK cells is lower in women with pelvic endometriosis. Therefore, evaluation of NKp46 on peripheral blood NK cells may provide a means of screening for reproductive abnormalities. Recently, a new type of NK cell, the NK22 cell, has been reported. This cell may be a regulator not only of the mucosal barrier but also of reproduction. For women with RPL showing abnormal uterine and/or peripheral blood NK cells, both intravenous immunoglobulin treatment and intralipid treatment have been reported. The effects of these treatments are still controversial, and further studies are needed in order to clarify their true impact. The present review examines variations in the expression of NCRs on NK cells, the participation of NK22 cells in reproduction, and the possible use of intravenous immunoglobulin or intralipid treatment for women with recurrent pregnancy loss and NK cell abnormality.

Characteristic of innate lymphoid cells (ILC)

Innate lymphoid cells (ILC) is a newly described family of immune cells that are part of the natural immunity which is important not only during infections caused by microorganisms, but also in the formation of lymphoid tissue, tissue remodeling after damage due to injury and homeostasis tissue stromal cells. Family ILC cells form NK cells (natural killer) and lymphoid tissue inducer T cells (LTi), which, although they have different functions, are evolutionarily related. NK cells are producing mainly IFN-γ, whereas LTi cells as NKR+LTi like, IL-17 and/or IL-22, which suggests that the last two cells, can also represent the innate versions of helper T cell--TH17 and TH22. Third population of ILC is formed by cells with characteristics such as NK cells and LTi (ILC22)--which are named NK22 cells, natural cytotoxicity receptor 22 (NCR22) cells or NK receptor-positive (LTi NKR+) LTi cells. Fourth population of ILC cells are ILC17--producing IL-17, while the fifth is formed by natural helper type 2 T cells (nTH2), nuocyte, innate type 2 helper cells (IH2) and multi-potent progenitor type 2 cells (MPPtype2). Cells of the last population synthesize IL-5 and IL-13. It is assumed that an extraordinary functional diversity of ILC family, resembles T cells, probably because they are under the control of the corresponding transcription factors - as direct regulation factors, such as the family of lymphocytes T.

The change of NCR expression and cytokine production of NK cells in peripheral blood and peritoneal fluid by hormonal treatment in patients with endometriosis

Problem: It is considered that NK22 cells might mediate mucosal immune defense in several organ. In response to pathogen, IL-23 stimulates NK22 cells to secrete IL-22. It is only reported that NK22 cells were present in the uterinemucosa. Toexamine theNK22 function,we investigated theproductionand relationof IL-22and theother cytokines using endometrium (EM) and peripheral blood (PB) NK cells of women with recurrent pregnancy loss (RPL). Materials and methods: Cytokines production (IFNgamma, TNF-alpha, IL-4, IL-10, IL-22, TGF-b1) by PB and EMNK cells and the expression of Nkp46were analyzed by triple color flow cytometry inwomenwith RPL (n=43) and controls (n=38). Moreover, we classified into four groups with high or low percentage of IL-22 production (RPL-H, RPL-L, Control-H and Control-L). Results: In EM, the percentage of NK22 cells in women with RPL was significantly higher than that of controls (p<0.05). In PB and EM, the percentage of IFN-gammaproducing NK22 cells in RPL-H was significantly lower than that in Control-L (p<0.05). There were negative correlations between NK22 cells, and IFN-gamma (r=−0.6) or TNF-alpha (r=−0.6) in women with RPL. There was a negative correlation between CD56bright/IL-22+ cells and CD56bright/NKp46+ cells (r=−0.271). Conclusions:NK22 cell might play an important role in women with RPL by regulating cytokine production by NK cells.

Flow cytometric analysis of NK22 cells function in peripheral blood and endometrium obtained from women with recurrent pregnancy loss

Problem: It is considered that NK22 cells might mediate mucosal immune defense in several organ. In response to pathogen, IL-23 stimulates NK22 cells to secrete IL-22. It is only reported that NK22 cells were present in the uterinemucosa. Toexamine theNK22 function,we investigated theproductionand relationof IL-22and theother cytokines using endometrium (EM) and peripheral blood (PB) NK cells of women with recurrent pregnancy loss (RPL). Materials and methods: Cytokines production (IFNgamma, TNF-alpha, IL-4, IL-10, IL-22, TGF-b1) by PB and EMNK cells and the expression of Nkp46were analyzed by triple color flow cytometry inwomenwith RPL (n=43) and controls (n=38). Moreover, we classified into four groups with high or low percentage of IL-22 production (RPL-H, RPL-L, Control-H and Control-L). Results: In EM, the percentage of NK22 cells in women with RPL was significantly higher than that of controls (p<0.05). In PB and EM, the percentage of IFN-gammaproducing NK22 cells in RPL-H was significantly lower than that in Control-L (p<0.05). There were negative correlations between NK22 cells, and IFN-gamma (r=−0.6) or TNF-alpha (r=−0.6) in women with RPL. There was a negative correlation between CD56bright/IL-22+ cells and CD56bright/NKp46+ cells (r=−0.271). Conclusions:NK22 cell might play an important role in women with RPL by regulating cytokine production by NK cells.

AB0040 Role of Innate Immunity in the Pathogenesis of Anca-Associated Vasculitis

BackgroundNatural killer (NK) cells represent one of the main effectors of the innate immune response. Toll-like receptors (TLRs) are a family of evolutionally-conserved host defense mechanism against pathogens. Recent evidence...

Innate lymphoid cells sustain colon cancer through production of interleukin-22 in a mouse model

Patients with inflammatory bowel disease (IBD) have an increased risk of colon cancer. However, the immune cells and cytokines that mediate the transition from intestinal inflammation to cancer are poorly understood. We show that bacteria-induced colon cancer is accompanied by differential accumulation of IL-17(+)IL-22(+) colonic innate lymphoid cells (cILCs), which are phenotypically distinct from LTi and NK-22 cells, and that their depletion in mice with dysplastic inflammation blocks the development of invasive colon cancer. Analysis of the functional role of distinct Type 17 cytokines shows that although blockade of IL-17 inhibits some parameters of intestinal inflammation, reduction in dysplasia and colorectal cancer (CRC) requires neutralization of IL-22 indicating a unique role for IL-22 in the maintenance of cancer in this model. Mechanistic analyses showed that IL-22 selectively acts on epithelial cells to induce Stat3 phosphorylation and proliferation. Importantly, we could detect IL-22(+)CD3(+) and IL-22(+)CD3(−) cells in human CRC. Our results describe a new activity of IL-22 in the colon as a nonredundant mediator of the inflammatory cascade required for perpetuation of CRC, highlighting the IL-22 axis as a novel therapeutic target in colon cancer.

The Aryl Hydrocarbon Receptor: A Sentinel Safeguarding the Survival of Immune Cells in the Gut

Innate lymphoid cells (ILCs) regulate the epithelial barrier function and immunity in the gut. How ILC numbers are maintained is unknown. In this issue of Immunity, Qiu et al. (2012) report that the transcription factor aryl hydrocarbon receptor controls survival and function of gut-residing ILCs.

Natural Killer-22 Cells in the Synovial Fluid of Patients with Rheumatoid Arthritis Are an Innate Source of Interleukin 22 and Tumor Necrosis Factor-α

To determine the role of natural killer (NK)-22 cells in the pathogenesis of rheumatoid arthritis (RA). Using flow cytometry, the proportions of NK-22 cells and intracellular contents of perforin, granzyme B, and interferon-γ (IFN-γ) were determined in the peripheral blood (PB) and synovial fluid (SF) of patients with RA and healthy individuals. The levels of interleukin 22 (IL-22) and tumor necrosis factor-α (TNF-α) in the NK-22 supernatant and gene expressions were measured using ELISA and QuantiGene Plex assay, respectively. The effect of NK-22 supernatant on the proliferation of fibroblast-like synoviocytes (FLS) and recombinant human IL-22 (rhIL-22) on the production of monocyte chemoattractant protein 1 (MCP-1) by RA FLS was detected using the yellow tetrazolium salt method and ELISA, respectively. The relationship between the proportions of NK-22 cells and disease activity was analyzed. NKp44 and CCR6 were expressed in a larger population of SF NK cells than in the PB NK cells of patients with RA. NK-22 cells produce low content of perforin, granzyme B, and IFN-γ. NK-22 cells in vitro can secrete IL-22 and TNF-α and there was increased messenger RNA coding for IL-22 and TNF-α. NK-22 supernatant can induce the proliferation of RA FLS. Addition of IL-22 antibody plus TNF-α antibody inhibited the proliferation of FLS induced by the NK-22 supernatant. Both rhIL-22 1 ng/ml and rhIL-22 10 ng/ml induced the production of MCP-1 by RA FLS. The NK-22 proportions were positively correlated with disease activity. NK-22 cells are increased in patients with RA and might play a role in the pathogenesis of RA through the production of IL-22 and TNF-α. The proportion of NK-22 cells and disease activity were highly correlated.

Development of IL-22–producing NK lineage cells from umbilical cord blood hematopoietic stem cells in the absence of secondary lymphoid tissue

AbstractHuman secondary lymphoid tissues (SLTs) contain interleukin-22 (IL-22)–producing cells with an immature NK phenotype. Given their location, these cells are difficult to study. We have generated large numbers of NK22 cells from hematopoietic stem cells. HSC-derived NK22 cells show a CD56+CD117highCD94− phenotype, consistent with stage III NK progenitors. Like freshly isolated SLT stage III cells, HSC-derived NK22 cells express NKp44, CD161, CCR6, IL1 receptor, AHR, and ROR-γτ. IL-1β and IL-23 stimulation results in significant IL-22 but not interferon-γ production. Supernatant from these cells increases CD54 expression on mesenchymal stem cells. Thus, IL-22–producing NK cells can be generated in the absence of SLT. HSC-derived NK22 cells will be valuable in understanding this rare NK subset and create the opportunity for human translational clinical trials.

Distinct Roles of IL-23 and IL-17 in the Development of Psoriasis-Like Lesions in a Mouse Model

Psoriasis is an inflammatory disease with dynamic interactions between the immune system and the skin. The IL-23/Th17 axis plays an important role in the pathogenesis of psoriasis, although the exact contributions of IL-23 and IL-17 in vivo remain unclear. K5.Stat3C transgenic mice constitutively express activated Stat3 within keratinocytes, and these animals develop skin lesions with histological and cytokine profiles similar to those of human plaque psoriasis. In this study, we characterized the effects of anti-mouse IL-17A, anti-mouse IL-12/23p40, and anti-mouse IL-23p19 Abs on the development of psoriasis-like lesions in K5.Stat3C transgenic mice. Treatment with anti-IL-12/23p40 or anti-IL-23p19 Abs greatly inhibited 12-O-tetradecanoylphorbol-13-acetate-induced epidermal hyperplasia in the ears of K5.Stat3C mice, whereas the inhibitory effect of an anti-IL-17A Ab was relatively less prominent. Treatment with anti-IL-12/23p40 or anti-IL-23p19 Abs markedly lowered transcript levels of Th17 cytokines (e.g., IL-17 and IL-22), β-defensins, and S100A family members in skin lesions. However, anti-IL-17A Ab treatment did not affect mRNA levels of Th17 cytokines. Crossing IL-17A-deficient mice with K5.Stat3C mice resulted in partial attenuation of 12-O-tetradecanoylphorbol-13-acetate-induced lesions, which were further attenuated by anti-IL-12/23p40 Ab treatment. FACS analysis of skin-draining lymph node cells from mice that were intradermally injected with IL-23 revealed an increase in both IL-22-producing T cells and NK-22 cells. Taken together, this system provides a useful mouse model for psoriasis and demonstrates distinct roles for IL-23 and IL-17.

In Vitro Generation of NK22 Cells From Hematopoietic Stem Cells

AbstractAbstract 108NK cells are the first lymphocytes to recover after allogeneic hematopotiec cell transplantation (allo-HCT). Rapid NK recovery after allo-HCT is associated with reduced treatment related mortality. Because NK cells elaborate inflammatory cytokines (IFN-g) and mediate cytotoxic killing of malignant cells, they are also implicated in graft vs. leukemia reactions. Curiously early after transplant, donor-derived NK cells are hypofunctional and immature. Over the past year, investigators identified a new category of NK cells, called NK22 cells. These cells are present in secondary lymphoid tissue, such as tonsils, lymph nodes and Peyer's patches. Previous investigators have not been able to identify NK22 cells in adult blood or UCB, likely due to lymphoid tissue homing receptor expression (CCR6 and CCR7). NK22 cells are CD56+/−CD117highCD94−IL-1bR+, a phenotype which overlaps with one previously used to describe NK progenitors (i.e., stage III immature NK cells). At present, it is not known whether NK22 cells are a distinct branch of the NK lineage or are NK developmental intermediates. NK22 cells are present in secondary lymphoid tissue at vanishingly small quantities (<1% of all mononuclear cells), thereby making the study of these cells challenging. Functionally, NK22 cells lack of “classical” NK functions (cytotoxicity and IFN-g production) and instead elaborate IL-22 in response to dendritic cell derived IL-1 and/or IL-23. IL-22 does not act on hematopoietic cells, but rather on mucosal tissues to induce proliferation, anti-apoptotic functions and the production of antimicrobial proteins (b defensins). NK22 cells also increase the expression of adhesion molecules on MSCs after co-culture, suggesting a role in secondary lymphoid generation and homeostasis. We have previously used a stromal cell based culture system to study NK development from hematopoietic stem cells. Briefly, CD34+ cells are cultured in the presence of IL-3 (for the first week), FLT-3L, SCF, IL-7 and IL-15 for ~4-5 weeks. At the end of this culture period, functional mature NK cells are obtained. Because this system closely recapitulates ontongeny, we hypothesized that it could be used to study NK22 development. At D28 of culture, we found that 90% (range=88-94%) of cells expressed CD56. Approximately 22% (range=16-28%) had a stage III immature NK cell phenotype (i.e., CD56+CD117highCD94−), of which ~87% (range=77-93%) also expressed IL-bR, a phenotype consistent with NK22 cells (n=5). We next purified CD56− and CD56+ cell populations in these cultures and neither showed IL-22 expression at rest. Following IL-1 and/or IL-23 stimulation, the CD56+ fraction made IL-22 transcripts (by qPCR) and protein by ELISA. We next purified the stage III (CD56+CD117highCD94−) and stage IV (CD56+CD117lowCD94+) fractions and found that only the stage III cells were capable of IL-22 production following IL-1/23 stimulation. Co-culture of NK22 cells (or their supernatant) with MSCs resulted in a >2 log increase in ICAM. Likewise, the supernatant of from activated stage III cells induced keritinocyte proliferation and production of antimicrobial compounds. In vitro derived NK22 cells were compared to freshly isolated NK22 cells from human tonsils and nearly identical staining patterns for ROR-gt, Acyl hydrocarbon receptor, NKp44, NKp46, CD127, CD161, CCR6 and CCR7 were observed. Lastly, purified CD56+CD117highCD94− cells could acquire IL-bR and then further differentiate into stage IV cells (CD56+CD117lowCD94+) in the presence of IL-15. However, this was less likely in the presence of IL-15 and IL-1b, suggesting that NK22 cells are developmental intermediates with specific functions (SLT homeostasis and maintenance of mucosal surfaces and immunity). Depending upon the environmental stimuli, these cells will either maintain their IL-22 producing capacity or develop into cytotoxic lymphocytes. These studies are the first studies to describe the generation of NK22 cells from hematopoietic stem cells. They also allow a better understanding of the developmental requirements and functions of these rare cells. Lastly, this simple culture system creates a new opportunity to use NK22 cells therapeutically to enhance SLT tissue repair and mucosal immunity after allo-HCT. Disclosures:No relevant conflicts of interest to declare.

Development and function of T H17 cells in health and disease

T(H)17 cells are the newest member of the T(H) cell family and are characterized by their ability to produce specific cytokines such as IL-17, IL-22, IL-17F, and CCL20. In this review, conditions for the differentiation of T(H)17 cells are defined in both murine and human systems, with discussion of T(H)17-specific cytokines and transcription factors. Functionally, T(H)17 cells contribute to host defense as a new effector T(H) cell subset with a role in protection against extracellular bacteria through activities on immune and nonimmune cells. Their activities, however, are also pivotal in the development of autoimmune diseases under pathologic conditions. T(H)17 cells are also beginning to be associated with the development and pathophysiology of allergic diseases, such as allergic contact dermatitis, atopic dermatitis, and asthma. Lymphoid tissue inducer-like cells and natural killer-like cells, termed RORgammat(+)NKp46(+) or NK-22 cells, might also play a role in allergic diseases because of their propensity to produce IL-17 and IL-22.

Stage 3 immature human natural killer cells found in secondary lymphoid tissue constitutively and selectively express the TH17 cytokine interleukin-22

AbstractConsiderable functional heterogeneity within human natural killer (NK) cells has been revealed through the characterization of distinct NK-cell subsets. Accordingly, a small subset of CD56+NKp44+NK cells, termed NK-22 cells, was recently described within secondary lymphoid tissue (SLT) as IL-22− when resting, with a minor fraction of this population becoming IL-22+ when activated. Here we discover that the vast majority of stage 3 immature NK (iNK) cells in SLT constitutively and selectively express IL-22, a TH17 cytokine important for mucosal immunity, whereas earlier and later stages of NK developmental intermediates do not express IL-22. These iNK cells have a surface phenotype of CD34−CD117+CD161+CD94−, largely lack expression of NKp44 and CD56, and do not produce IFN-γ or possess cytolytic activity. In summary, stage 3 iNK cells are highly enriched for IL-22 and IL-26 messenger RNA, and IL-22 protein production, but do not express IL-17A or IL-17F.

A human natural killer cell subset provides an innate source of IL-22 for mucosal immunity

Natural killer (NK) cells are classically viewed as lymphocytes that provide innate surveillance against virally infected cells and tumour cells through the release of cytolytic mediators and interferon (IFN)-gamma. In humans, blood CD56(dim) NK cells specialize in the lysis of cell targets. In the lymph nodes, CD56(bright) NK cells secrete IFN-gamma cooperating with dendritic cells and T cells in the generation of adaptive responses. Here we report the characterization of a human NK cell subset located in mucosa-associated lymphoid tissues, such as tonsils and Peyer's patches, which is hard-wired to secrete interleukin (IL)-22, IL-26 and leukaemia inhibitory factor. These NK cells, which we refer to as NK-22 cells, are triggered by acute exposure to IL-23. In vitro, NK-22-secreted cytokines stimulate epithelial cells to secrete IL-10, proliferate and express a variety of mitogenic and anti-apoptotic molecules. NK-22 cells are also found in mouse mucosa-associated lymphoid tissues and appear in the small intestine lamina propria during bacterial infection, suggesting that NK-22 cells provide an innate source of IL-22 that may help constrain inflammation and protect mucosal sites.