Blockade of CD300A enhances the ability of human NK cells to lyse hematologic malignancies

Objective: The human cluster of differentiation(CD)300A, a type-I transmembrane protein with immunoreceptor tyrosine-based inhibitory motifs, was investigated as a potential immune checkpoint for human natural killer(NK) cells targeting hematologic malignancies(HMs).Methods: We implemented a stimulation system involving the CD300A ligand, phosphatidylserine(PS), exposed to the outer surface of malignant cells. Additionally, we utilized CD300A overexpression, a CD300A blocking system, and a xenotransplantation model to evaluate the impact of CD300A on NK cell efficacy against HMs in in vitro and in vivo settings. Furthermore, we explored the association between CD300A and HM progression in patients.Results: Our findings indicated that PS hampers the function of NK cells. Increased CD300A expression inhibited HM lysis by NK cells. CD300A overexpression shortened the survival of HM-xenografted mice by impairing transplanted NK cells. Blocking PS–CD300A signals with antibodies significantly amplified the expression of lysis function-related proteins and effector cytokines in NK cells, thereby augmenting the ability to lyse HMs. Clinically, heightened CD300A expression correlated with shorter survival and an “exhausted” phenotype of intratumoral NK cells in patients with HMs or solid tumors.Conclusions: These results propose CD300A as a potential target for invigorating NK cell-based treatments against HMs.

Decreased LDHB expression in breast tumor cells causes NK cell activation and promotes tumor progression

Objective: Abnormal metabolism is the underlying reason for breast cancer progression. Decreased lactate dehydrogenase B(LDHB) has been detected in breast cancer but the function of LDHB remains unknown.Methods: Western blot was used to analyze LDHB expression in breast cancer cells. The impact of LDHB on tumor cell migration and invasion was determined using Transwell assays, wound healing assays, and a mouse lung metastasis model. Subcutaneous tumor formation, a natural killer(NK) cell cytotoxicity assay, and flow cytometry evaluated NK cell activation. Immunofluorescence and quantitative real-time PCR detected NK cell activation markers. Kaplan-Meier analysis evaluated the effect of immune cell infiltration on prognosis. Single-sample gene set enrichment analysis determined NK cell activation scores. A support vector machine predicted the role of LDHB in NK cell activation.Results: In this study we showed that LDHB inhibits the breast cancer cell metastasis and orchestrates metabolic reprogramming within tumor cells. Our results revealed that LDHB-mediated lactic acid clearance in breast cancer cells triggers NK cell activation within the tumor microenvironment. Our findings, which were confirmed in a murine model, demonstrated that LDHB in tumor cells promotes NK cell activation and ultimately results in the eradication of malignant cells. Clinically, our study further validated that LDHB affects immune cell infiltration and function. Specifically, its expression has been linked to enhanced NK cell-mediated cytotoxicity and improved patient survival. Furthermore, we identified LDHB expression in tumors as an important predictor of NK cell activation, with strong predictive ability in some cancers.Conclusions: Our results suggest that LDHB is a promising target for activating the tumor immune microenvironment in breast cancer, where LDHB-associated lactic acid clearance leads to increased NK cell activity. This study highlights the critical role of LDHB in regulating immune responses and its potential as a therapeutic target for breast cancer.

Internalization of NK cells into tumor cells requires ezrin and leads to programmed cell-in-cell death

Cytotoxic lymphocytes are key players in the orchestration of immune response and elimination of defective cells. We have previously reported that natural killer （NK） cells enter target tumor ceils, leading to either target cell death or self-destruction within tumor cells. However, it has remained elusive as to the fate of NK cells after internalization and whether the heterotypic cell-in-cell process is different from that of the homotypic cell-in-cell event recently named entosis. Here, we show that NK cells undergo a cell-in-cell process with the ultimate fate of apoptosis within tumor cells and reveal that the internalization process requires the actin cytoskeletal regulator, ezrin. To visualize how NK cells enter into tumor cells, we carried out real-time dual color imaging analyses of NK cell internalization into tumor cells. Surprisingly, most NK cells commit to programmed cell death after their entry into tumor cells, which is distinctively different from entosis observed in the homotypic cell-in-cell process. The apoptotic cell death of the internalized NK cells was evident by activation of caspase 3 and DNA fragmentation. Furthermore, NK cell death after internalization is attenuated by the caspase inhibitor, Z-VAD-FMK, confirming apoptosis as the mode of NK cell death within tumor cells. To determine protein factors essential for the entry of NK cells into tumor cells, we car- ried out siRNA-based knockdown analysis and discovered a critical role of ezrin in NK cell internalization. Impor- tantly, PKA-mediated phosphorylation of ezrin promotes the NK cell internalization process. Our findings suggest a novel regulatory mechanism by which ezrin governs NK cell internalization into tumor cells.

Expression of prolactin receptor and response to prolactin stimulation of human NK cell lines

We have previously shown a critical role of prolactin (PRL) during maturation and anti-tumor effects of murine natural killer (NK) cells in vitro and in vivo. We extended that study by exploring the ability of human NK cell lines (NK-92 and YT cell) to express PRL receptor (PRL-R) and to respond to PRL stimulation in vitro. Both human NK cell lines constitutively expressed PRL-R on membrane and mRNA transcripts,NK-92 cells contained higher level of PRL-R than YT cells,which correlated to the enhanced capacity of the cells to proliferate and to lyse target cells in response to PRL stimulation in the presence of trace amount of IL-2 or IL-15 in vitro. Two differences between IL-2 and IL-15 in functioning on human NK cells were for the first time observed. PRL synergized with IL-15 to improve proliferation of NK cells in a dose-dependent manner without double peak manifesting like IL-2. Although PRL enhanced the cytotoxicity of IL-2 or IL- 15 activated NK cells,it exerted the function through up-regulating gene expression of perforin without influence of FasL in IL-2-stimulated NK cells,while in IL-15-stimulated NK cells,PRL did the function through up-regulating gene expression of both perforin and FasL but not IFNγ. PRL increased expressions of IL-2Rα on membrane and of IL-2 mRNA in cells,indicating that PRL up-regulated NK cell function by improving positive feedback between IL-2 and IL-2R. The similar results were also observed in network between IL-15 and IL-15R. These data indicate a potential role of PRL in human NK cell modulation.

不同强度低氧训练对NK CELL活性的损害效应研究

目的:研究不同强度低氧训练后大鼠脾NK细胞活性的变化,探讨不同强度、不同低氧训练方式对机体免疫功能的影响。方法:120只大鼠按照氧环境(常氧、高住低练、低氧)和训练强度(无、中和高强度)随机形成9种组合,中等强度训练5周,高强度训练6周,乳酸脱氢酶释放法测定NK活性。结果:训练强度、氧环境与训练强度的交互作用对NK细胞活性具有显著影响;常氧高强度训练能显著提高NK细胞活性,低氧和高住低练高强度训练对NK活性无促进作用;常氧、低氧环境下中等强度训练对NK活性无显著影响,但高住低练环境下中等强度训练会严重损害NK细胞功能。结论:低氧和高住低练环境下高强度训练不利于NK活性的提高;高住低练环境下长期中等强度训练会严重降低NK细胞功能。

The Role of NK Cell in T Cell Recruitment in Murine Liver Infected with Adenovirus

To study the role of natural killer (NK) cells in T cell recruitment in murine liver infected with virus, mice were intravenously injected daily with anti-NK1.1 + antibody to deplete NK cells. Lymphocytes in the liver tissue of mice infected with type 5 adenovirus depleted in the E1 and E3 regions were assessed by fluorometric activated cell sorting (FACS). Expression of chemokine IP-10 and its receptor CXCR3 mRNA in the liver, hepatic lymphocytes and spleen tissue were examined by reverse transcription polymerase chain reaction (RT-PCR). Serum alanine aminotransferase (ALT) was measured as an indicator of liver injury. It was found that infection of adenovirus and anti-Fas monoclonal antibody (mAb) into mice caused liver injury and high expression of interferon-γ inducible protein-10 (IP-10) mRNA in the liver. Anti-NK1.1 + mAb, which was intraperitoneally injected into the mice infected with adenovirus, suppresses T cell recruitment and expression of IP-10 mRNA in the liver. Slighter liver injury was also observed. After virus infection, expression of CXCR3 mRNA in spleen and liver tissue was observed at different time. The results suggested that T cell recruitment was initiated by NK cell dependent chemokine IP-10, which induced activated T cells priming in the spleen to the liver of the mouse. NK cells played a key role in T cell recruitment in the liver of mouse infected with adenovirus.

Study on T lymphocyte subsets and NK cells in patients with Graves' disease combined with type 2 diabetes

Objective To investigate changes in T lymphocyte subsets and NK cells in patients with simple Graves’ disease(GD)and Graves’ disease combined with type 2 diabetes mellitus(GD/T2DM).Methods Fifteen cases of GD/T2DM were selected from our hospital from November 2001 to November 2004.Before and after therapy thyroid function,thyroglobulin antibody(TGA),thyroid microsomal antibody(TMA)and blood glucose level were measured,and T lymphocyte subsets(CD3,CD4,CD8,CD4/CD8)and NK cells(CD56)were measured by immunofluorescence double labeling monoclonal antibody and flow cytometry,respectively.At the same time,comparison was made with simple GD(15 cases),T2DM(15 cases)and healthy control(20 cases).Results Before therapy,CD4/CD8,CD4 and NK cells in GD/T2DM were less than normal,and there was no significant difference in comparison with simple GD(P<0.05).In T2DM group,only CD4/CD8 and CD4 were less than those of healthy controls(P<0.05).When thyroid function recovered after 1 to 3 months of methimazole treatment in both GD/T2DM and simple GD groups,various indexes recovered,which were more obvious in simple GD.Conclusion Immune hypofunction of GD may be the key to the immune abnormality of GD/T2DM,which is more significant than that of simple GD or T2DM.The recovery of thyroid function and immune abnormality is not consistent,and the recovery of GD is more significant than that of GD/T2DM.

Studies on Activity of NK Cells in Preeclampsia Patients

The activity of the NK cells in patients with preeclampsia was studied to investigate the pathogenesis of preeclampsia. By using MTT and 51Cr releasing technique, the proliferation and killing ability of the NK cells in maternal and umbilical blood from preeclampsia patients (n=18) and normal third trimester pregnant women (n=18) were detected. The NK-92 cell line was as the positive control. The results showed that the NK cell counts of umbilical blood in preeclampsia patients and normal third trimester pregnant women were significantly greater than those of maternal blood (both P<0.05). Compared with that in normal third trimester pregnant women, the proliferative ability of the NK cells in preeclampsia patients was apparently increased (P<0.05). Compared with that in maternal blood, the proliferative ability of the NK cells in umbilical blood from both preeclampsia patients and normal third trimester pregnant women was dramatically increased. The killing ability of the NK cells in preeclampsia patients was significantly higher than that in normal third trimester pregnant women (P <0.05). It was suggested that both number and function of the NK cells in preeclampsia women were increased, and that in umbilical blood was greater than that in maternal blood, speculating that the function of the NK cells may affect the maintenance of the maternal and fetal immune tolerance during pregnancy.

IgE PRODUCTION IS INVOLVED IN BUTYRATE- ENHANCED NK CELL ACTIVITY IN VIVO

It has been demonstrated that patients with asthma have a large number of NK cells and show a stronger NK activity. These results indicate that NK cell activity may be related to total IgE level in serum in healthy subjects. Previously,we have found that sodium butyrate (NaBu) markedly enhanced the IL- 4- induced IgE production in the LPS- stimulated murine splenocytes in vitro, and inductive rat IgE production in vivo, and enhanced the NK cell activity ex vivo .We hypothesized that the IgE production might be involved in butyrate- enhanced NK cell activity in vivo. Mice were intraperitoneally treated/immunized with NaBu or/and Ascaris suum extract (ASC),and the spleen NK cell activity was evaluated. Furthermore, the effect of serum (NAS) on IL- 2- or IFN-γ- induced spleen NK cell activity was determined. The spleen NK cell activity and IL- 2- or IFN-γ- induced spleen NK cell activity of mice treated/immunized with NaBu or/and ASC were stronger than those of untreated/unimmunized mice. Although IL- 4 blocked IL- 2 (100 U/ml)- or IFN-γ (100 U/ml)- induced increase in NK cell activity,these NK cell activities in mice treated/immunized with NaBu/ASC were not inhibited. IgE production showed a tendency to rise in NaBu- treated mice serum, and a synergistic effect was observed with treatment of NaBu and ASC. Moreover, the NAS significantly increased IL- 2(25 U/ml)- or IFN-γ (25 U/ml)- induced NK cell activity, and its effect was inhibited by anti- mouse IgE mAb. These data show that IgE plays an important role in NAS- enhanced IL- 2/IFN-γ- induced NK cell activity, and IL- 4 does not inhibit IgE and IL- 2/IFN-γ- induced NK cell activity in mice.

Research on the effects of CD137 signaling on the function of CD3^-CD56^+NK cells

Objective： To investigate the effects of CD137 signaling on the regulation of CD3-CD56＋NK cells function. Methods： CD3 CD56＋NK cells were treated with CD137 mAb or mouse IgG 1 isotype control to study the effects of CD 137 signaling on the function of CD3-CD56＋NK cells. Cytotoxicity was measured by LDH activity in the supernatants of cell cultures; NKG2D and LFA-I expression on CD3-CD56＋NK cells were analyzed by flow cytometry. Results： CD137 was expressed on activated CD3-CD56＋NK cells. The CD137 mAb enhanced the ability of CDB-CD56＋NK cells to kill lung cancer cells（A549）; Further studies revealed that the expression of NKG2D and LFA-1 was significantly increased in activated cells, and blockade of NKG2D and LFA-1 dramatically attenuated CD3CD56＋NK cytolysis of A549 cancer cells. Conclusion： CD 137 signaling increases the ability of CD3-CD56＋NK cells to kill cancer cells via up- regulating the expression of NKG2D and LFA-1.

Effect of Mg^(2+)level on the functions of CD8^(+)T lymphocytes and NK cells in patients with COVID-19

Objective:To investigate the changes of Mg^(2+) levels in serum and peripheral blood mononuclear cells(PBMCs)of patients with COVID-19 and its effects on the functions of CD8^(+)T lymphocytes and NK cells.Methods:A total of 165 COVID-19 patients hospitalized in Ezhou Central Hospital from January 20 to February 20,2020 were divided into mild/common group(98 cases)and severe/critical group(67 cases).At the same time,34 healthy persons were selected as the control group.Peripheral blood was collected and PBMCs were isolated,the level of Mg^(2+) in serum and PBMCs was detected.The subsets of CD8^(+)T lymphocytes and NK cell and the expression levels of their surface inhibitory molecular PD-1 and activator molecular NKG2D were detected by flow cytometry.The correlation between Mg^(2+) concentration and the expression levels of PD-1 and NKG2D was also analyzed.Results:Compared with the control group,the concentration of Mg^(2+) in serum and PBMCs,the counts of CD8^(+)T lymphocytes and NK cell in patients with mild/common and severe/critical groups were significantly reduced(P<0.05),while the expression level of surface inhibitory molecular PD-1 were significantly increased(P<0.05),while the expression level of the activation molecule NKG2D were significantly decreased(P<0.05).However,the changes of the above indicators in patients with severe/critical group were greater than those in the mild/common group(P<0.05).In addition,the Mg^(2+) concentration in COVID-19 patients was negatively correlated with the expression level of PD-1 on CD8^(+)T lymphocytes and NK cells(P<0.05),and positively correlated with the expression levels of NKG2D(P<0.05).Conclusion:The concentration of Mg^(2+) in the serum and PBMCs of COVID-19 patients is significantly reduced,which may cause the function of CD8^(+)T lymphocytes and NK cells to be inhibited.

Im m unoregulatory Effects of Triptergium W ilfordii Hook at Antifertility Dose on Splenic NK Cells Activityin Male Mice

Effects of Tripterypium Wilfordii Hook f (TWH) on sperm atozoa in the epi- didym is and splenic NK cells activity in m ale m ice w ere observed using MTT assay and silver impregnation m ethods. The results show ed that the density, viability and m otility of the epididym alsperm atozoa in the experim entalgroupstreated w ith TWH w ere m ore significantly reduced than those in the controlgroup (P< 0.01). The head sw elling, head separation from tailin the groups treated w ith TWH w ere observed. The inhibition of splenicNK cellsactivity in m iceby TWH w asdose-dependent. Inhi- bition by TⅡand TWH athigh dose on the NK cells activity w as significant (P< 0.01 and P< 0.05), w hileinhibitory effectsof TWH atinterm ediateand low doseson the NK cells activity w ere notobserved (P> 0.05). Itw as concluded thatTWH at low er antifertility dose did not significantly inhibit the splenic NK cells activity. It m ightbe usefulforevaluating thetherapeuticeffectsof TWH in futureclinicalprac- tice.

Case Report: Feasibility and Safety of Autologous NK Cell Therapy in Patients with Cancer

This study reported two cases of Thai cancer patients, including a 36-year-old female with thyroid cancer of more than 5 years and a 64-year-old male with lung and colon cancers of more than 10 years. The written informed consent was provided for autologous natural killer (NK) cell infusion at the anti-ageing and regenerative medicines clinic. Briefly, the blood was taken from the patient for NK cell count and their cytotoxic activity. Then, the patient’s NK cells were expanded in vitro, characterized and then counted before being delivered to the same patient by a single intravenous infusion. The vital signs and general physical examinations were observed for 2 - 6 hours after the infusion. The patients were discharged if there were no adverse effects. The data showed the increasing number of NK cells and level of cytotoxic activity after the NK cell treatment, compared to the pre-treatment. In addition, the increasing total live cell concentration, as identified by the high percentage of CD56dim/CD16bright cytotoxic NK cells, at day 21 of the NK cell expansion was consistent with the increasing cytotoxic activity of the patients after the treatment. Here, we demonstrated that this autologous NK cell therapy might be feasible;however, the study did not aim to evaluate the anti-cancer effect.

Relation between Neurotransmitters and NK Cells in Adrenal and Breast Cancer

Purpose: Data on microarray gene expression The Gene Expression Omnibus (GEO) provided information on gene expression. Transcription GEO provided two profiles of human NK cells from breast and adrenal tumors (GSE179509 and GSE143383). Data processing and normalization The Dseq2 tool in the R programming language was used to standardize the raw data from GEO. The following analyses were carried out: fold change and P-value analysis, volcano plot, network analysis, GEPIA, and David pathway analysis. In this paper, using Venny software, we discovered 2 genes that are shared by neurotransmitters and NK cells in breast cancer and adrenal cancer. Between these genes and the pathways, they are a part of, we discovered a network. Pathway analysis revealed that these genes are mostly linked to the neurotransmitter and apoptotic pathways. In breast and adrenal tumors, the genes HRH1 and GABRD were discovered to be connected to NK cells. In response to breast and adrenal tumors, almost all of these genes are effective. It is thus postulated that the diagnosis of breast and adrenal cancer may be affected by the up-or down-regulation of these genes. Methods: Microarray gene expression data gene expression data was obtained from the Gene Expression Omnibus (GEO) Transcription 2 profile data of human NK cells from human breast and adrenal cancers were obtained from GEO (GSE179509 and GSE143383). Processing and normalization of data the raw data from GEO were normalized with the Dseq2 package in the R software. Fold change and P value analysis, Volcano plot, network analysis, GEPIA, and David pathway analysis were performed. Results: In this article, we found genes common to neurotransmitters with NK cells in adrenal cancer and breast cancer with Venny program, resulting in 2 genes. We identified a network between these genes and pathways they belong to. Pathway analysis showed that these genes are mostly associated with apoptosis and neurotransmitters pathway. Conclusion: HRH1 and GABRD genes were found to be associated with NK cells in breast and adrenal cancers. Almost all these genes are effective in response to breast and adrenal cancers. Therefore, it is hypothesized that downregulation or upregulation of these genes may affect breast and adrenal cancer diagnosis.

Interleukin-15 Promotes the Commitment of Cord Blood CD34^+ Stem Cells into NK Cells

To explore the effect of rhIL-15 on CB-CD34 + stem cells committing to NK cells, CD34 + stem cells were obtained from cord blood (CB) by magnetic-assisted cell sorting (MACS) method. CD3, CD16 and CD56 molecules expressed on cell surface were detected by flow cytometer. MTT method was used to test the cytotoxicity of NK cells. The results were that stem cell factor (SCF) alone has no effect on CD34 + stem cells. IL-15 stimulated CD34 + stem cells commit to NK cells, and SCF showed strong synergistic effect with IL-15. It was concluded that IL-15 and SCF played different roles during NK cell development, IL-15 promoted CD34 + stem cells differentiate to NK cell precursor and SCF improved the effects of IL-15 on NK cell differentiation.

The PI3K/Akt/GSK-3β/ROS/eIF2B pathway promotes breast cancer growth and metastasis via suppression of NK cell cytotoxicity and tumor cell susceptibility

Objective: To examine the effect of pSer9-GSK-3β on breast cancer and to determine whether the underlying metabolic and immunological mechanism is associated with ROS/eIF2B and natural killer(NK) cells.Methods: We employed TWS119 to inactivate GSK-3β by phosphorylating Ser9 and explored its effect on breast cancer and NK cells. The expression of GSK-3β, natural killer group 2 member D(NKG2D) ligands, eIF2B was quantified by PCR and Western blot. We measured intracellular reactive oxygen species(ROS) and mitochondrial ROS using DCFH-DA and MitoSOX^(TM) probe,respectively, and conducted quantitative analysis of cellular respiration on 4T1 cells with mitochondrial respiratory chain complex Ⅰ/Ⅲ kits.Results: Our investigation revealed that TWS119 downregulated NKG2D ligands(H60 a and Rae1), suppressed the cytotoxicity of NK cells, and promoted the migration of 4T1 murine breast cancer cells. Nevertheless, LY290042, which attenuates p-GSK-3β formation by inhibiting the PI3K/Akt pathway, reversed these effects. We also found that higher expression of p Ser9-GSK-3β induced higher levels of ROS, and observed that abnormality of mitochondrial respiratory chain complex Ⅰ/Ⅲ function induced the dysfunction of GSK-3β-induced electron transport chain, naturally disturbing the ROS level. In addition, the expression of NOX3 and NOX4 was significantly up-regulated, which affected the generation of ROS and associated with the metastasis of breast cancer. Furthermore, we found that the expression of pSer535-eIF2B promoted the expression of NKG2D ligands(Mult-1 and Rae1) following by expression of pSer9-GSK-3β and generation of ROS.Conclusions: The PI3K/Akt/GSK-3β/ROS/eIF2B pathway could regulate NK cell activity and sensitivity of tumor cells to NK cells,which resulted in breast cancer growth and lung metastasis. Thus, GSK-3β is a promising target of anti-tumor therapy.

Participation of CD45,NKR-P1A and ANK61 antigen in rat hepatic NK cell(pit cell)-mediated target cell cytotoxicity

AIM Several triggering receptors have beendescribed to be involved in natural killer（NK）cell-mediated target cytotoxicity.In these studies,NKcells derived from blood or spleen were used.Pitcells are liver-specific NK cells that possess ahigher level of natural cytotoxicity and a differentmorphology when compared to blood NK cells.The aim of this study was to characterize the roleof the NK-triggering molecules NKR-P1A,ANK61antigen,and CD45 in pit cell-mediated killing oftarget cells.METHODS 51Cr-release and DNA fragmentationwere used to quantify target cell lysis andapoptosis,respectively.RESULTS Flow cytometric analysis showed thatpit cells expressed CD45,NKR-P1A,and ANK61antigen.Treatment of pit cells with monoclonalantibody（mAb）to CD45（ANK74）not onlyinhibited CC531s or YAC-1 target lysis but alsoapoptosis induced by pit cells.The mAbs to NKR-P1A（3.2.3）and ANK61 antigen（ANK61）had no effect on pit cell-mediated CC531s or YAC-1 targetcytolysis or apoptosis,while they did increase theFcγ receptor positive（FcγR+）P815 cytolysis andapoptosis.This enhanced cytotoxicity could beinhibited by 3,4-dichloroisocoumarin,an inhibitorof granzymes.CONCLUSION These results indicate that CD45participates in pit cell-mediated CC531s and YAC-1target cytolysis and apoptosis.NKR-P1A andANK61 antigen on pit cells function as activationstructures against FcγR+ P815 cells,which wasmediated by the perforin/granzyme pathway.

The Association between Expression of NK Cells and Prognosis of Patients with HBV Acute-on-Chronic Liver Failure in Advanced Phase

Acute-on-chronic liver failure (Acute-on-chronic liver failure, ACLF) is acute liver function decompensation on the basis of chronic liver disease. The progression of ACLF develops from advanced phase, plateau phase to remission phase. The pathophysiological basis of ACLF in different phases is various. In advanced phase, immune imbalance and systemic inflammatory reaction plays key roles. In this study, we try to assess the association between expression of NK cells and its receptors and prognosis of patients with ACLF in advanced phase. A total of 35 inpatients with HBV acute-on-chronic liver failure in advanced phase were recruited. They were divided into case group (n = 18) and control group (n = 17) according to whether the patients was dead in the 12 weeks. PBMC were detected for the frequency and expression of NK cell receptors by flow cytometric analysis. Our results demonstrated that patients who died had lower expression of NK cells and inhibitory receptor KIR3DL1, higher levels of FASL. During 12-week follow-up in those case alive, we found that NK cells increased, while expression of FASL decreased. High short-term mortality of ALCF was associated with NK cell, especially related to KIR3DL1 and FASL (PNK = 0.036, PKIR3DL1 = 0.0265, PFasL = 0.0008).

Increased Activity of NK Cells and Plasmacytoid Dendritic Cells in HIV-Exposed Seronegative (ESN) Individuals

The mechanisms involved in resistance to HIV-1 infection, especially the role of innate immune response, have not been thoroughly explored in individuals who are repeatedly exposed to HIV-1, but do not get the infection, termed as Exposed sero-negative or ESN. Frequency and activation state of natural killer (NK) cells and plasmacytoid dendritic cells (pDC) in ESNs from North India were compared with those in recently infected HIV positives (RHIV), chronically infected HIV positives (HIV+) and healthy controls (HC). The activation state of NK cells in terms of cytokine response (IFNγ & TNFα) was significantly higher in ESNs compared to the healthy controls, recently infected HIV+ and chronically infected HIV+. Although the number of circulating pDC in different study groups was not significantly different, yet these cells seem to have significantly higher activation state in terms of IFNα production (ex-vivo in response to CpG ODN) in ESNs when compared with other groups. Increased activation status of NK cells and pDC in Exposed but Seronegative individuals indicates their continuous stimulation with HIV antigens due to regular exposure with infected partners and which might be imparting resistance to viral infection in these individuals.

Elevated Birth Rates in CD62L (L-Selectin)-Deficient BALB/c Mice: Potential Involvement of NK Cells

Background: L-selectin (CD62L) is a cell surface adhesion molecule recently shown to play a critical role in determining endometrial receptivity and implantation in humans. By contrast, the L-selectin ligand is missing from the rodent endometrium. Interestingly, CD62L (L-selectin)-deficient BALB/c mice delivered significantly higher numbers of viable offspring than wild type controls via mechanisms yet to be defined. Methods: Nulliparous CD62L-deficient (8-10-week-old, n = 25) or wild type (n = 18) females were mated with 43 age-matched males. Animals were sacrificed at gestational day (GD) 9.5. Tissue samples were analyzed by immunostaining and flow cytometry. Results: Mating wild type and CD62L-deficient BALB/c mice revealed that the increased birth rate was due to the CD62L deficiency in females. Flow cytometric analysis demonstrated significant differences in the number of natural killer (NK) cells present in the uterus of pregnant CD62L- deficient mice compared to controls. Immunohistochemistry confirmed NK cell accumulation at the fetal-maternal interface. Discussion: Uterine NK cells have been shown to peak at GD 8-10 at the fetal-maternal interface. NK cells might regulate mouse fertility rates by facilitating development of the maternal spiral arteries, thereby stimulating the formation of larger vessels that facilitate intrauterine survival, however, their role is not obligate to spiral artery development. Conclusions: Diminished CD62L expression modified immune cell trafficking into the uterus of pregnant mice generating a microenvironment primarily dominated by NK cells resulting in improved embryonic survival rates.