Characterisation of regulatory T cells in nasal associated lymphoid tissue in children: relationships with pneumococcal colonization

Regulatory T cells (Treg) diminish immune responses to microbial infection, which may contribute to preventing inflammation-related local tissue damage and autoimmunity but may also contribute to chronicity of infection. Nasopharyngeal carriage of pneumococcus is common in young children and can persist for long periods but it is unknown whether the presence of Treg in the nasopharynx contributes to this persistence. We have investigated the numbers and activities of Foxp3+Treg in adenoidal tissues and their association with pneumococcal carriage in children. Expression of Treg cell-related markers including Foxp3, CD25, CD39, CD127 and CLTA4 were analysed by flow-cytometry in adenoidal mononuclear cells (MNC) and PBMC from children. Unfractionated MNC or Treg-depleted MNC were stimulated with a pneumococcal whole cell antigen (WCA) and T cell proliferation measured. Cytokine production by MNC was measured using a cytometric bead array. Higher numbers of CD25(high)Foxp3(high) Treg expressing higher CD39 and CTLA4 were found in adenoidal MNC than in PBMC. Children with pneumococcus positive nasopharyngeal cultures had higher proportions of Treg and expressed higher levels of CD39 and CTLA-4 than those who were culture negative (-). WCA induced adenoidal Treg proliferation which produce IL10 but not IL17, and CD4 T cell proliferation in Treg-depleted MNC was greater in pneumococcal culture positive than negative children. Significant numbers of Treg with an effector/memory phenotype which possess a potent inhibitory effect, exist in adenoidal tissue. The association of pneumococcal carriage with an increased frequency of adenoidal Treg suggests that Treg in nasal-associated lymphoid tissue (NALT) may contribute to the persistence of pneumococcus in children. Further studies to determine what component and mechanisms are involved in the promotion of Treg in NALT may lead to novel therapeutic or vaccination strategy against upper respiratory infection.     

Dendritic cells and T lymphocyte interactions in patients with lymphoid malignancies

Dendritic cell (DC) vaccination is an attractive approach to the treatment of patients with lymphoid tumors. To evaluate its feasibility, we have tested the functional properties of DC and T-lymphocytes in patients with treated and untreated chronic lymphocytic leukemia (CLL) and follicular lymphoma (FL). Healthy volunteers were used both as controls and as a source of cells for allogeneic mixed leukocyte reaction (MLR). In these reactions, dendritic cells from both untreated and treated patients were comparable to dendritic cells from healthy volunteers. In all the untreated patients studied, autologous dendritic cells promoted the survival and proliferation of both CD4 and CD8 lymphocytes (though the proliferation response was much better in the CD4 subset), whereas only 3 out of 5 treated patients were able to mount this response with CD4 lymphocytes and 4 out of 5 with CD8 lymphocytes. In 3 out of 5 untreated patients, pulsing of DCs with tetanus toxoid promoted a better CD4 response than was achieved with unpulsed DCs, while none of 5 treated patients had an additional response after pulsing with tetanus toxoid. None of patients studied, either treated or untreated, had a better CD8 response to pulsed DCs than to unpulsed ones. During CD4 lymphocyte proliferation, more CD4(+)CD25(hi) lymphocytes were generated in both treated and untreated patients than in healthy controls. Poor proliferation of cytotoxic cells and preferential proliferation of CD4(+)CD25(hi) T-regulatory cells in response to self and/or foreign antigens might be one of the mechanisms responsible for immunosuppression and impaired tumor surveillance in patients with lymphoid malignancies.     

The detection of viral hepatitis markers in HIV-infected patients

The determination of markers of virus hepatitides B, C and D in 63 registered HIV-infected persons was made. The use of Russian and foreign EIA systems permitted the detection of markers of virus hepatitides 30.1% of HIV-infected persons, including 26.3% of children. Markers of hepatitis B virus were found to occur in children and adults with the same frequency. Out of 65 persons registered in the Center, 3 persons (4.6%) were drug addicts; of these, 2 were found to have antibodies to antigens of hepatitis viruses. Such persons constituted 3.8% of the total number of HIV-infected persons. Among 8 newly detected and registered HIV-infected adults, 2 were found to have antibodies to hepatitis B virus (of these, 1 used drugs intravenously).     

The development and function of memory regulatory T cells after acute viral infections

Leptospira interrogans is responsible for a zoonotic disease known to induce severe kidney dysfunction and inflammation. In this work, we demonstrate that L. interrogans induces NLRP3 inflammasome-dependent secretion of IL-1β through the alteration of potassium transport in bone marrow-derived macrophages. Lysosome destabilization also contributed to the IL-1β production upon stimulation with live, but not dead, bacteria. Using bone marrow-derived macrophages from various TLRs and nucleotide-binding oligomerization domain-deficient mice, we further determined that IL-1β production was dependent on TLR2 and TLR4, suggesting a participation of the leptospiral LPS to this process. Hypokaliemia in leptospirosis has been linked to the presence of glycolipoprotein, a cell wall component of L. interrogans that is known to inhibit the expression and functions of the Na/K-ATPase pump. We show in this study that glycolipoprotein activates the inflammasome and synergizes with leptospiral LPS to produce IL-1β, mimicking the effect of whole bacteria. These results were confirmed in vivo, as wild-type mice expressed more IL-1β in the kidney than TLR2/4-deficient mice 3 d postinfection with L. interrogans. Collectively, these findings provide the first characterization, to our knowledge, of bacteria-induced activation of the NLRP3 inflammasome through the downregulation of a specific host potassium transporter.     

Acquisition of pneumococci specific effector and regulatory Cd4+ T cells localising within human upper respiratory-tract mucosal lymphoid tissue

The upper respiratory tract mucosa is the location for commensal Streptococcus (S.) pneumoniae colonization and therefore represents a major site of contact between host and bacteria. The CD4(+) T cell response to pneumococcus is increasingly recognised as an important mediator of immunity that protects against invasive disease, with data suggesting a critical role for Th17 cells in mucosal clearance. By assessing CD4 T cell proliferative responses we demonstrate age-related sequestration of Th1 and Th17 CD4(+) T cells reactive to pneumococcal protein antigens within mucosal lymphoid tissue. CD25(hi) T cell depletion and utilisation of pneumococcal specific MHCII tetramers revealed the presence of antigen specific Tregs that utilised CTLA-4 and PDL-1 surface molecules to suppress these responses. The balance between mucosal effector and regulatory CD4(+) T cell immunity is likely to be critical to pneumococcal commensalism and the prevention of unwanted pathology associated with carriage. However, if dysregulated, such responses may render the host more susceptible to invasive pneumococcal infection and adversely affect the successful implementation of both polysaccharide-conjugate and novel protein-based pneumococcal vaccines.     

Depletion of regulatory T cells in HIV infection is associated with immune activation

Immune activation during chronic HIV infection is a strong clinical predictor of death and may mediate CD4(+) T cell depletion. Regulatory T cells (Tregs) are CD4(+)CD25(bright)CD62L(high) cells that actively down-regulate immune responses. We asked whether loss of Tregs during HIV infection mediates immune activation in a cross-sectional study of 81 HIV-positive Ugandan volunteers. We found that Treg number is strongly correlated with both CD4(+) and CD8(+) T cell activation. In multivariate modeling, this relationship between Treg depletion and CD4(+) T cell activation was stronger than any other clinical factor examined, including viral load and absolute CD4 count. Tregs appear to decline at different rates compared with other CD4(+) T cells, resulting in an increased regulator to helper ratio in many patients with advanced disease. We hypothesize that this skewing may contribute to T cell effector dysfunction. Our findings suggest Tregs are a major contributor to the immune activation observed during chronic HIV infection.     

Foxp3+ regulatory T cells control persistence of viral CNS infection

We earlier established a model of a persistent viral CNS infection using two week old immunologically normal (genetically unmodified) mice and recombinant measles virus (MV). Using this model infection we investigated the role of regulatory T cells (Tregs) as regulators of the immune response in the brain, and assessed whether the persistent CNS infection can be modulated by manipulation of Tregs in the periphery. CD4(+) CD25(+) Foxp3(+) Tregs were expanded or depleted during the persistent phase of the CNS infection, and the consequences for the virus-specific immune response and the extent of persistent infection were analyzed. Virus-specific CD8(+) T cells predominantly recognising the H-2D(b)-presented viral hemagglutinin epitope MV-H(22-30) (RIVINREHL) were quantified in the brain by pentamer staining. Expansion of Tregs after intraperitoneal (i.p.) application of the superagonistic anti-CD28 antibody D665 inducing transient immunosuppression caused increased virus replication and spread in the CNS. In contrast, depletion of Tregs using diphtheria toxin (DT) in DEREG (depletion of regulatory T cells)-mice induced an increase of virus-specific CD8(+) effector T cells in the brain and caused a reduction of the persistent infection. These data indicate that manipulation of Tregs in the periphery can be utilized to regulate virus persistence in the CNS.     

21例侵袭性肺曲霉病患者Th以及Treg细胞的检测

目的：分析侵袭性肺曲霉病患者辅助性T细胞（Th）以及调节性T细胞（Treg）在外周血中单个核细胞中的表达情况及其临床相关性,探讨Th和Treg细胞介导的免疫反应在侵袭性肺曲霉病中的作用。方法分离21例侵袭性肺曲霉病患者及19例健康人外周血的单个核细胞,采用流式细胞术分析Th1、Th2、Th17、Treg细胞群的表达情况,Real-timePCR方法检测相关转录因子T-bet、GATA-3、RORγt以及Foxp3的表达,ELISA法检测血清中相关细胞因子IFN-γ、IL-4、IL-17以及TGF-β的表达。结果与健康人对照组相比,侵袭性肺曲霉病患者Th1细胞以及Treg细胞占CD4＋T细胞的比例较之对照组明显降低;Th1、Th17、Treg细胞相关转录因子T-bet、RORγt、Foxp3以及相关细胞因子IFN-γ、IL-17A、TGF-β与对照组相比表达明显降低。结论IPA患者的Th1、Th17以及Treg细胞所介导的免疫反应受抑制。     

Novel elvitegravir nanoformulation approach to suppress the viral load in HIV-infected macrophages

PurposeMonocytes serve as sanctuary sites for HIV-1 from which virus is difficult to be eliminated. Therefore, an effective viral suppression in monocytes is critical for effective antiretroviral therapy (ART). This study focuses on a new strategy using nanoformulation to optimize the efficacy of ART drugs in HIV-infected monocytes.MethodsPoly(lactic-co-glycolic acid) (PLGA)-based elvitegravir nanoparticles (PLGA-EVG) were prepared by nano-precipitation technique. The physicochemical properties of PLGA-EVG were characterized using transmission electron microscopy, dynamic light scattering, and Fourier-transform infrared spectroscopy. Cellular uptake study was performed by fluorescence microscopy and flow cytometry. All in vitro experiments were performed by using HIV-infected monocytic cell lines U1 and HIV-infected primary macrophages. Elvitegravir quantification was performed using LC-MS/MS. HIV viral replication was assessed by using p24 ELISA.ResultsWe developed a PLGA-EVG nanoparticle formulation with particle size of ~ 47 nm from transmission electron microscopy and zeta potential of ~ 6.74 mV from dynamic light scattering. These nanoparticles demonstrated a time- and concentration-dependent uptakes in monocytes. PLGA-EVG formulation showed a ~ 2 times higher intracellular internalization of EVG than control group (EVG alone). PLGA-EVG nanoparticles also demonstrated superior viral suppression over control for a prolonged period of time.ConclusionsPLGA-based EVG nanoformulation increased the intracellular uptake of EVG, as well as enhanced viral suppression in HIV-infected macrophages, suggesting its potential for improved HIV treatment in monocytic cells.     

Transplantation survival is maintained by granzyme B+ regulatory cells and adaptive regulatory T cells

Granzyme B (GZB) has been implicated as an effector mechanism in regulatory T cells (T(reg)) suppression. In a model of T(reg)-dependent graft tolerance, it is shown that GZB- deficient mice are unable to establish long-term tolerance. Moreover, mice overexpressing the inhibitor of GZB, serine protease inhibitor 6, are also resistant to tolerization to alloantigen. Graft survival was shorter in bone marrow-mixed chimeras reconstituted with GZB-deficient T(reg) as compared with wild-type T(reg). Whereas there was no difference in graft survival in mixed chimeras reconstituted with wild-type, perforin-deficient, or Fas ligand-deficient T(reg). Finally, data also show that if alloreactive effectors cannot express FoxP3 and be induced to convert in the presence of competent T(reg), then graft tolerance is lost. Our data are the first in vivo data to implicate GZB expression by T(reg) in sustaining long-lived graft survival.     

GRAIL is up-regulated in CD4+ CD25+ T regulatory cells and is sufficient for conversion of T cells to a regulatory phenotype

GRAIL (gene related to anergy in lymphocytes) is an ubiquitin-protein isopeptide ligase (E3) ubiquitin ligase necessary for the induction of CD4(+) T cell anergy in vivo. We have extended our previous studies to characterize the expression pattern of GRAIL in other murine CD4(+) T cell types with a described anergic phenotype. These studies revealed that GRAIL expression is increased in naturally occurring (thymically derived) CD4(+) CD25(+) T regulatory cells (mRNA levels 10-fold higher than naive CD25(-) T cells). Further investigation demonstrated that CD25(+) Foxp3(+) antigen-specific T cells were induced after a "tolerizing-administration" of antigen and that GRAIL expression correlated with the CD25(+) Foxp3(+) antigen-specific subset. Lastly, using retroviral transduction, we demonstrated that forced expression of GRAIL in a T cell line was sufficient for conversion of these cells to a regulatory phenotype in the absence of detectable Foxp3. These data demonstrate that GRAIL is differentially expressed in naturally occurring and peripherally induced CD25(+) T regulatory cells and that the expression of GRAIL is linked to their functional regulatory activity.     

Cell surface markers of regulatory T cells are not associated with increased forkhead box p3 expression in blood CD4+ T cells from HIV-infected patients responding to antiretroviral therapy

Regulatory T (Treg) cells may attenuate host immune responses to pathogens, including HIV and opportunistic pathogens in HIV-infected patients. Treated and untreated progressive HIV disease represent a range of immunological scenarios with potentially different roles for Treg cells. A cell surface marker to determine Treg cell numbers would assist in identifying situations where Treg cells are important. Here we show that levels of Foxp3 mRNA are increased in CD4+ T cells from HIV-infected patients responding to antiretroviral therapy. However, the proportion of peripheral blood CD4+ and CD8+ T cells expressing CD25, neuropilin-1, glucocorticoid-induced TNF receptor and lymphocyte activation gene-3 did not differ as a result of treated or untreated HIV infection when compared with HIV-seronegative controls. Hence, none of the putative Treg cell surface markers identified T-cell populations in peripheral blood that mirrored the effects of HIV infection and antiretroviral therapy on Foxp3 expression.     

哮喘患者外周血Treg和Th1/Th2的变化及其与哮喘病情的关系

目的：探讨哮喘患者外周血调节性T细胞（Treg）以及辅助性T细胞（Th1/Th2）的比例的变化,探讨其在哮喘的临床治疗中的作用。方法：80例哮喘患者（哮喘组）按临床表现分为急性发作期组（54例）和缓解期组（26例）,同时选择50例健康体检者。应用流式细胞仪检测上述各组外周血CD4＋CD25＋Foxp3＋Treg、CD4＋IFN-γ＋Th1和CD4＋IL-4＋Th2细胞水平,并进行统计学分析。结果：哮喘组CD4＋CD25＋Foxp3＋Treg水平亦明显低于正常对照组（P〈0.05。其中急性发作期组Treg水平明显低于缓解期组和正常对照组（P〈0.05）。而哮喘组Th1/Th2比值显著低于对照组（P〈0.05）,且在哮喘急性发作组中Th1/Th2比值显著低于缓解期组和正常对照组（P〈0.05）。结论：提示Treg和Th在哮喘的发生和发展中起着重要的作用。     

哮喘患者外周血Treg和Th1/Th2的变化及其与哮喘病情的关系

目的:探讨哮喘患者外周血调节性T细胞(Treg)以及辅助性T细胞(Th1/Th2)的比例的变化,探讨其在哮喘的临床治疗中的作用。方法:80例哮喘患者(哮喘组)按临床表现分为急性发作期组(54例)和缓解期组(26例),同时选择50例健康体检者。应用流式细胞仪检测上述各组外周血CD4+CD25+Foxp3+Treg、CD4+IFN-γ+Th1和CD4+IL-4+Th2细胞水平,并进行统计学分析。结果:哮喘组CD4+CD25+Foxp3+Treg水平亦明显低于正常对照组(P<0.05。其中急性发作期组Treg水平明显低于缓解期组和正常对照组(P<0.05)。而哮喘组Th1/Th2比值显著低于对照组(P<0.05),且在哮喘急性发作组中Th1/Th2比值显著低于缓解期组和正常对照组(P<0.05)。结论:提示Treg和Th在哮喘的发生和发展中起着重要的作用。     

The osteopontin level in liver, adipose tissue and serum is correlated with fibrosis in patients with alcoholic liver disease

Background

Osteopontin (OPN) plays an important role in the progression of chronic liver diseases. We aimed to quantify the liver, adipose tissue and serum levels of OPN in heavy alcohol drinkers and to compare them with the histological severity of hepatic inflammation and fibrosis.

Methodology/Principal Findings

OPN was evaluated in the serum of a retrospective and prospective group of 109 and 95 heavy alcohol drinkers, respectively, in the liver of 34 patients from the retrospective group, and in the liver and adipose tissue from an additional group of 38 heavy alcohol drinkers. Serum levels of OPN increased slightly with hepatic inflammation and progressively with the severity of hepatic fibrosis. Hepatic OPN expression correlated with hepatic inflammation, fibrosis, TGFβ expression, neutrophils accumulation and with the serum OPN level. Interestingly, adipose tissue OPN expression also correlated with hepatic fibrosis even after 7 days of alcohol abstinence. The elevated serum OPN level was an independent risk factor in estimating significant (F≥2) fibrosis in a model combining alkaline phosphatase, albumin, hemoglobin, OPN and FibroMeter® levels. OPN had an area under the receiving operator curve that estimated significant fibrosis of 0.89 and 0.88 in the retrospective and prospective groups, respectively. OPN, Hyaluronate (AUROC: 0.88), total Cytokeratin 18 (AUROC: 0.83) and FibroMeter® (AUROC: 0.90) estimated significance to the same extent in the retrospective group. Finally, the serum OPN levels also correlated with hepatic fibrosis and estimated significant (F≥2) fibrosis in 86 patients with chronic hepatitis C, which suggested that its elevated level could be a general response to chronic liver injury.

Conclusion/Significance

OPN increased in the liver, adipose tissue and serum with liver fibrosis in alcoholic patients. Further, OPN is a new relevant biomarker for significant liver fibrosis. OPN could thus be an important actor in the pathogenesis of this chronic liver disease.