Clinical significance of costimulatory molecules CD40/CD40L and CD134/CD134L in coronary heart disease: A case-control study.

The aim of the study was to evaluate the potential role of CD40/CD40 ligand (CD40L) and CD134/CD134 ligand (CD134L) in the development of coronary heart disease (CHD) via the performance of a case-control study.The research objects were 234 cases of CHD patients and 120 cases of well-matched normal controls. Following the separation of peripheral blood mononuclear cells (PBMCs), real-time quantitative PCR (qRT-PCR), Western blot, immunohistochemistry, and flow cytometry were applied for the detection of mRNA levels and expression levels of CD40/CD40L and CD134/CD134L; meanwhile, intercellular adhesion molecule-1 (ICAM-1) and Fas protein mRNA levels were detected using qRT-PCR.There was no statistical difference in the comparison of baseline characteristics between groups, indicating comparability between groups. qRT-PCR and Western blot analysis indicated that CD40/CD40L and CD134/CD134L mRNA and protein expression levels were all increased in the CHD group than those in the control group. Flow cytometry further confirmed the similar tendency. Meanwhile, ICAM-1 and Fas protein mRNA levels were elevated in the CHD group and positively correlated with the above parameters. Furthermore, CD40/CD40L expression rates were negatively correlated with gender and different types of CHD. Meanwhile, CD134/CD134L expressions were also higher in male patients, in patients with family history, previous history of hypertension, diabetes, and cerebrovascular diseases.CD40/CD40L and CD134/CD134L are increased and may have potential correlation with clinical pathological features of patients with CHD. Further in-depth exploration of costimulatory molecules for CHD guidance as well as intrinsic mechanisms are needed combined with in vivo and in vitro experiments.

Oncolytic Adenovirus and Tumor-Targeting Immune Modulatory Therapy Improve Autologous Cancer Vaccination.

Oncolytic viruses selectively lyse tumor cells, disrupt immunosuppression within the tumor, and reactivate antitumor immunity, but they have yet to live up to their therapeutic potential. Immune checkpoint modulation has been efficacious in a variety of cancer with an immunogenic microenvironment, but is associated with toxicity due to nonspecific T-cell activation. Therefore, combining these two strategies would likely result in both effective and specific cancer therapy. To test the hypothesis, we first constructed oncolytic adenovirus Delta-24-RGDOX expressing the immune costimulator OX40 ligand (OX40L). Like its predecessor Delta-24-RGD, Delta-24-RGDOX induced immunogenic cell death and recruit lymphocytes to the tumor site. Compared with Delta-24-RGD, Delta-24-RGDOX exhibited superior tumor-specific activation of lymphocytes and proliferation of CD8+ T cells specific to tumor-associated antigens, resulting in cancer-specific immunity. Delta-24-RGDOX mediated more potent antiglioma activity in immunocompetent C57BL/6 but not immunodeficient athymic mice, leading to specific immune memory against the tumor. To further overcome the immune suppression mediated by programmed death-ligand 1 (PD-L1) expression on cancer cells accompanied with virotherapy, intratumoral injection of Delta-24-RGDOX and an anti-PD-L1 antibody showed synergistic inhibition of gliomas and significantly increased survival in mice. Our data demonstrate that combining an oncolytic virus with tumor-targeting immune checkpoint modulators elicits potent in situ autologous cancer vaccination, resulting in an efficacious, tumor-specific, and long-lasting therapeutic effect. Cancer Res; 77(14); 3894-907. ©2017 AACR.

Epigenetic-mediated immune suppression of positive co-stimulatory molecules in chemoresistant ovarian cancer cells.

The immunological response against cancer is a critical balance between immune-activating and immune-suppressing mechanisms. Ovarian cancer creates a suppressive microenvironment to escape immune elimination; however, the molecular mechanisms are poorly understood, and it is unclear whether chemotherapeutic drugs exert an immunoreactive or immunosuppressive effect on the tumor microenvironment. 4-1BB ligand (4-1BBL/CD157) and OX-40 ligand (OX-40L/CD252) are important regulators of effector cytotoxic T-cells activity. This study demonstrates that expression of positive co-stimulatory molecules, OX-40L and 4-1BBL, is suppressed while expression of immunosuppressive molecule programmed death ligand-1 (PD-L1/CD274) is enhanced in chemoresistant cells compared to parental chemosensitive ovarian cancer cells. Here, the molecular mechanisms of silencing of OX-40L and 4-1BBL expression were investigated in chemoresistant A2780-AD ovarian cancer cells. The suppression of OX-40L and 4-1BBL are due to DNA hypermethylation and histone deacetylation, two important mechanisms that contribute to gene silencing during cancer progression. We identify important epigenetic regulators, histone deacetylase 1/3 (HDAC1/HDAC3) and DNA methyltransferase 1 (DNMT1), that exhibit aberrant association with OX-40L and 4-1BBL promoters in chemoresistant ovarian cancer cells. Knockdown of HDAC1 or DNMT1 expression, and pharmacological inhibition of DNMT or HDAC enzymatic activity, significantly increase OX-40L and 4-1BBL expression in chemoresistant cells. This study suggests that loss of histone acetylation and accumulation of DNA methylation correlates with suppressed expression of OX-40L and 4-1BBL in chemoresistant ovarian cancer cells. This study marks the first report of the regulation of these two molecules by histone deacetylation and DNA methylation in chemoresistant ovarian cancer cells.

Vaccination with Irradiated Autologous Tumor Cells Mixed with Irradiated GM-K562 Cells Stimulates Antitumor Immunity and T Lymphocyte Activation in Patients with Recurrent Malignant Glioma.

PURPOSE: Recurrent malignant glioma carries a dismal prognosis, and novel therapies are needed. We examined the feasibility and safety of vaccination with irradiated autologous glioma cells mixed with irradiated GM-K562 cells in patients undergoing craniotomy for recurrent malignant glioma. EXPERIMENTAL DESIGN: We initiated a phase I study examining the safety of 2 doses of GM-K562 cells mixed with autologous cells. Primary endpoints were feasibility and safety. Feasibility was defined as the ability for 60% of enrolled subjects to initiate vaccination. Dose-limiting toxicity was assessed via a 3+3 dose-escalation format, examining irradiated tumor cells mixed with 5 × 10(6) GM-K562 cells or 1 × 10(7) GM-K562 cells. Eligibility required a priori indication for resection of a recurrent high-grade glioma. We measured biological activity by measuring delayed type hypersensitivity (DTH) responses, humoral immunity against tumor-associated antigens, and T-lymphocyte activation. RESULTS: Eleven patients were enrolled. Sufficient numbers of autologous tumor cells were harvested in 10 patients, all of whom went on to receive vaccine. There were no dose-limiting toxicities. Vaccination strengthened DTH responses to irradiated autologous tumor cells in most patients, and vigorous humoral responses to tumor-associated angiogenic cytokines were seen as well. T-lymphocyte activation was seen with significantly increased expression of CTLA-4, PD-1, 4-1BB, and OX40 by CD4(+) cells and PD-1 and 4-1BB by CD8(+) cells. Activation was coupled with vaccine-associated increase in the frequency of regulatory CD4(+) T lymphocytes. CONCLUSIONS: Vaccination with irradiated autologous tumor cells mixed with GM-K562 cells is feasible, well tolerated, and active in patients with recurrent malignant glioma. Clin Cancer Res; 22(12); 2885-96. ©2016 AACR.

Human T-cell leukemia virus type 1 (HTLV-1) Tax1 oncoprotein but not HTLV-2 Tax2 induces the expression of OX40 ligand by interacting with p52/p100 and RelB.

Human T-cell leukemia virus type 1 (HTLV-1) is a causative retrovirus of adult T-cell leukemia and HTLV-1-associated myelopathy. Unlike HTLV-1, the same group of retrovirus HTLV-2 has not been found to be associated with these diseases. HTLV-1 and HTLV-2 encode transforming proteins Tax1 and Tax2, and a few distinct activities of Tax1 from those of Tax2 have been proposed to contribute to the HTLV-1-specific pathogenesis of disease. One significant difference of Tax1 from Tax2 is the activation of transcription factor NF-κB2/p100/p52. We found that Tax1 but not Tax2 induces the expression of OX40 ligand (OX40L) in a human T-cell line. To induce the OX40L expression, Tax1 but not Tax2 was observed to interact with NF-κB2/p100/p52 and RelB and the distinct interaction activity was mediated by the Tax1 amino acid region of 225-232. In addition, Tax1 but not Tax2 or Tax1/225-232 interacted with p65, p50, and c-Rel; however, the interactions were much less than those noted with NF-κB2/p100/p52 and RelB. OX40L is a T-cell costimulatory molecule of the tumor necrosis factor family, and its signal plays a critical role in establishing adaptive immunity by inducing the polarized differentiation of T-cells to cells such as T helper type 2 and T follicular helper cells. Therefore, the present findings suggest that Tax1 might alter the immune response to HTLV-1 and/or differentiation of HTLV-1-infected T-cells via OX40L induction, thereby acting as a factor mediating the distinct phenotypes and pathogenesis of HTLV-1 from that of HTLV-2.

Effects of OX40-OX40 ligand interaction on the levels of ROS and Cyclophilin A in C57BL/6J mice atherogenesis.

BACKGROUND: An increasing amount of evidence shows that the OX40-OX40L interaction serves an important function in atherosclerosis. However, the mechanism of the OX40 signaling pathway remains unclear. This study investigates the effect of OX40-OX40L interaction on the levels of intracellular reactive oxygen species (ROS) and the secretion of Cyclophilin A (CyPA) in C57BL/6J mice atherogenesis. METHODS: The atherosclerotic plaque model was established by placing a rapid perivascular carotid collar on C57BL/6J mice fed with a western-type diet. In vivo, the expressions of CyPA in mouse plaque and lymphocytes were detected by immunohistochemical and Western blot analyses, respectively. In vitro, the expression of CyPA protein in cultured lymphocytes of C57BL/6J mice was assessed by using Western blot analysis. The level of ROS was detected through flow cytometry. RESULTS: CyPA expression was significantly increased in the atherosclerotic lesions and lymphocytes from C57BL/6J mice. The ROS levels in OX40(+)-lymphocytes were increased in vitro and in vivo. After stimulating the OX40-OX40L interaction, the ROS and CyPA levels in lymphocytes were obviously increased in vitro, whereas anti-OX40L mAb significantly down-regulated the anti-OX40 mAb-induced ROS generation and inhibited CyPA secretion in lymphocytes. CONCLUSION: The OX40-OX40L interaction up-regulates intracellular levels of ROS in C57BL/6J mice and increases CyPA secretion in lymphocytes. Increased CyPA secretion may serve an important function in atherosclerotic plaque formation.

OX40 ligand: a potential costimulatory molecule in atopic asthma.

OBJECTIVE: We aimed to assess the percentage of peripheral blood B-lymphocytes expressing OX40 ligand (OX40L) in adult atopic and non-atopic asthmatic patients, and in healthy controls. METHODS: This case-control study included 15 atopic asthmatic patients, 15 non-atopic asthmatic patients, and 15 healthy controls. Atopic status was determined by skin prick test reaction to the most common locally-encountered allergens. For all subjects, pulmonary function tests and measurement of total serum immunoglobulin E (IgE) levels by ELISA were performed. In addition, the percentage of B-lymphocytes expressing OX40L was assessed by flow cytometry in all three groups. RESULTS: OX40L expression was significantly higher in atopic asthmatics than in non-atopic asthmatics and controls, but did not differ significantly between non-atopic asthmatics or controls. Among atopic asthmatics, OX40L expression correlated positively with total serum IgE levels, but not with age, disease duration, or values of forced expiratory volume in the first second. CONCLUSION: The over-expression of OX40L in atopic asthmatic patients appears to be linked to markers of the atopic status as total serum IgE, and signifies the vital role of OX40L in the atopic mechanism. Further large-scale studies are needed to investigate the role of OX40L in other atopic diseases and its relation to disease activity and severity.

The chronicity of tonsillitis is significantly correlated with an increase in an LTi cell portion.

The current study explored the relationship between lymphoid tissue inducer (LTi) cells and patients' clinical and immunological status. LTi cells are critical for lymphoid tissue development and maintenance of CD4 T cell-dependent immune responses. The percentage of CD117+CD3-CD56-CD127+ RORγ+ LTi cells isolated from human tonsils was determined and correlated with changes in other immune subsets and clinical factors. We found that the portion of LTi and CD4 T cells was significantly increased in chronic tonsillitis compared to non-inflamed tonsils. Additionally, the expression of OX40 by memory CD4 T cells and OX40 ligand (OX40L) and interleukin (IL)-22 by LTi cells was higher in chronically inflamed tonsils. The treatment for tonsillitis with ibuprofen did not alter LTi cell viability and the expression of OX40L and IL-22. These results demonstrate that during chronic inflammation, LTi cells are increased and express higher levels of OX40L and IL-22, and this is correlated with an increase in memory CD4 T cells.

OX40-OX40L expression in idiopathic inflammatory myopathies.

OBJECTIVE: To examine whether both OX40 and its ligand OX40L are expressed in idiopathic inflammatory myopathies and to investigate the types of inflammatory cells expressing OX40L. STUDY DESIGN: Immunohistochemistry was performed in limb muscle specimens from dermatomyositis, polymyositis and inclusion body myositis patients to analyze the expression of OX40 and its ligand OX40L. Double immunofluorescence labeling was performed to clarify the phenotype of inflammatory cells expressing OX40L. RESULTS: OX40 and OX40L expressing cells were observed in all subsets of inflammatory myopathies following a similar pattern of distribution mainly in the perimysium. In polymyositis and inclusion body myositis inflammatory cells expressing the receptors invaded non-necrotic muscle fibers. OX40L expression was also found in endothelial blood cells in all dermatomyositis and some polymyositis specimens. In all subsets of inflammatory myopathies OX40L was expressed by T cells (CD4+ and CD8+), macrophages (CD68+), B cells (CD20+) and myeloid dendritic cells (BDCA1+). Plasmacytoid dendritic cells (BDCA2+) expressing OX40L were found only in dermatomyositis and polymyositis. CONCLUSION: The simultaneous expression of both OX40 and its ligand OX40L in idiopathic inflammatory myopathies suggests that they might participate in disease pathogenesis. Expression of OX40L by different types of cells within the inflamed muscle implies that OX40-OX40L interaction may contribute in disease mechanisms through different pathways.

Highly active antiretroviral therapy in patients infected with human immunodeficiency virus increases CD40 ligand expression and IL-12 production in cells ex vivo.

Highly active anti-retroviral therapy (HAART) restores CD4(+) T-cell numbers in the periphery; however, its efficacy in restoring functional immunity is not fully elucidated. Here we evaluated longitudinal changes in the expression of several key markers of T-cell activation, namely CD40 ligand (CD154), OX40 (CD134), or CD69, after anti-CD3/CD28 activation, as well as levels of IL-12 production after Staphylococcus aureus Cowan stimulation in 28 HIV-infected adult patients. Patients were followed up to 12 mo post-HAART initiation. Viral burdens and CD4 cell counts were measured at the same time points. A control group of 15 HIV-uninfected adult subjects was included for comparison. Significant increases in CD40L and OX40 expression, but not of CD69 expression, were observed over time in the overall patient population, and more particularly in patients with baseline CD4 counts lower than or equal to 200 cells/µL, or those with baseline viral loads lower than or equal to 10(5) RNA copies/mL. Similar increases were seen for IL-12 production. Viral loads were inversely associated with CD40L expression or IL-12 production in a mixed linear model analysis, while CD4 counts were directly associated. CD40L expression and IL-12 production were significantly correlated. In conclusion, HAART-mediated control of viral replication led to partial restoration of CD40L upregulation/expression, and to increased IL-12 production, but the magnitude of the response depended on the baseline characteristics of the treated patients.

Maternal Foxp3 expressing CD4+ CD25+ and CD4+ CD25- regulatory T-cell populations are enriched in human early normal pregnancy decidua: a phenotypic study of paired decidual and peripheral blood samples.

PROBLEM: Regulatory T cells (Treg cells), a small subset of CD4(+) T cells maintaining tolerance by immunosuppression, are proposed contributors to the survival of the fetal semiallograft. We investigated Treg cells in paired decidual and peripheral blood (PB) samples from healthy women in early pregnancy and PB samples from non-pregnant women. METHOD OF STUDY: Distribution, location, cytokine mRNA, and phenotype were assessed in CD4(+) CD25(+) Treg cells from paired samples using immunohistochemistry, immunofluorescence, flow cytometry, and real-time quantitative RT-PCR. RESULTS: The presence and in situ distribution of CD4(+) Foxp3(+) Treg cells in decidua are hereby demonstrated for the first time. Three Foxp3(+) cell populations, CD4(+) CD25(++) Foxp3(+), CD4(+) CD25(+) Foxp3(+), and CD4(+) CD25(-) Foxp3(+), were enriched locally in decidua. In contrast, no statistically significant difference in numbers of circulating Treg cells between pregnant and non-pregnant women was found. The Foxp3(+) cells expressed the surface molecules CD45RO, CTLA-4, CD103, Neuropilin-1, LAG-3, CD62L, and TGFß1 mRNA consistent with Treg phenotype. The population of CD4(+) CD25(-) Foxp3(+) cells, not described in human decidua before, was enriched 10-fold compared with PB in paired samples. Their cytokine expression was often similar to Th3 profile, and the Foxp3 mRNA expression level in CD4(+) CD25(-) cells was stable and comparable to that of CD4(+) CD25(+) Treg cells implying that the majority of CD4(+) CD25(-) Foxp3(+) cells might be naïve Treg cells. CONCLUSION: (i) There is a local enrichment of Treg cells in decidua (ii) The exclusive accumulation of decidual CD4(+) CD25(-) Foxp3(+) cells suggests an additional reservoir of Foxp3(+) naïve Treg cells that can be converted to 'classical' Treg cells in uterus.

Campylobacter jejuni lipooligosaccharides modulate dendritic cell-mediated T cell polarization in a sialic acid linkage-dependent manner.

Carbohydrate mimicry between Campylobacter jejuni lipooligosaccharides (LOS) and host neural gangliosides plays a crucial role in the pathogenesis of Guillain-Barré syndrome (GBS). Campylobacter jejuni LOS may mimic various gangliosides, which affects the immunogenicity and the type of neurological deficits in GBS patients. Previous studies have shown the interaction of LOS with sialic acid-specific siglec receptors, although the functional consequences remain unknown. Cells that express high levels of siglecs include dendritic cells (DCs), which are crucial for initiation and differentiation of immune responses. We confirm that α2,3-sialylated GD1a/GM1a mimic and α2,8-sialylated GD1c mimic LOS structures interact with recombinant Sn and siglec-7, respectively. Although the linkage of the terminal sialic acid of LOS did not regulate expression of DC maturation markers, it displayed clear opposite expression levels of interleukin-12 (IL-12) and OX40L, molecules involved in DC-mediated Th cell differentiation. Accordingly, targeting DC-expressed siglec-7 with α2,8-linked sialylated LOS resulted in Th1 responses, whereas Th2 responses were induced by targeting with LOS containing α2,3-linked sialic acid. Thus, our data demonstrate for the first time that depending on the sialylated composition of Campylobacter jejuni LOS, specific Th differentiation programs are initiated, possibly through targeting of distinct DC-expressed siglecs.

HDAC11 plays an essential role in regulating OX40 ligand expression in Hodgkin lymphoma.

In Hodgkin lymphoma (HL), the malignant cells are surrounded by a large number of reactive infiltrating inflammatory cells, including OX40-expressing T cells and interleukin 10 (IL-10)-producing regulatory T (T-reg) cells. These T-reg cells can suppress the immune response and thus contribute to the maintenance of immune tolerance and to insufficient antitumor response. The engagement of OX40L with the OX40 receptor is essential for the generation of antigen-specific memory T cells and for the induction of host antitumor immunity. In the present study, we investigated whether histone deacetylase inhibitors (HDACis) may induce a favorable antitumor immune response by regulating the expression of OX40L in HL. We found that HDACis up-regulated OX40L surface expression in HL cell lines in a dose-dependent manner. Small interfering RNAs (siRNAs) that selectively inhibited HDAC11 expression, significantly up-regulated OX40L and induced apoptosis in HL cell lines, and silencing HDAC11 transcripts increased the production of tumor necrosis-α (TNF-α) and IL-17 in the supernatants of HL cells. Furthermore, HDACI-induced OX40L inhibited the generation of IL-10-producing type 1 T-reg cells. These results demonstrate for the first time that HDAC11 plays an essential role in regulating OX40L expression. Pharmacologic inhibition of HDAC11 may produce a favorable antitumor immune response in patients with HL.

Positive correlation between pregnancy-associated plasma protein-A level and OX40 ligand expression in patients with acute coronary syndromes.

OBJECTIVE: Increasing evidence show that serum pregnancy-associated plasma protein-A (PAPP-A) and OX40 ligand (OX40L) expression have been implicated in acute coronary syndromes (ACS). We investigated the relationship between PAPP-A level and OX40L in serum and membrane-bound OX40L in patients with ACS. METHODS: The present study included normal controls (n=30), patients with stable angina (SA) (n=60) and patients with ACS, including unstable angina (UA) (n=50) and acute myocardial infarction (AMI) (n=30). Serum concentrations of PAPP-A and soluble OX40L (sOX40L) were determined with Elisa, whereas the expression of OX40L on monocytes were analyzed with flow cytometry. RESULTS: The expression of OX40L in peripheral monocytes in patients with UA [25.6±5.5 mean fluorescence intensity (MFI)] and AMI (29.4±6.3MFI) were significantly higher than those in patients with SA (10.6±2.8MFI) and controls (11.1±3.5MFI). Both sOX40L and PAPP-A in patients with UA (15.7±4.9ng/mL, 25.4±6.8µg/mL, respectively) and AMI (17.1±5.3ng/mL, 26.3±5.6µg/mL, respectively) were significantly higher than those in patients with SA (3.4±1.4ng/mL, 9.6±2.1µg/mL, respectively) and controls (3.9±1.3ng/mL, 8.5±2.8µg/mL, respectively) (P<0.001). Interestingly, a positive correlation was found between sOX40L, membrane-bound OX40L and serum PAPP-A levels (r(1)=0.54, r(2)=0.51; P<0.0001). Both serum and membrane-bound OX40L and PAPP-A levels significantly correlated with complex coronary stenosis (r(1)=0.56, r(2)=0.55, r(3)=0.40; P<0.001). CONCLUSION: PAPP-A level was significantly related to soluble and membrane-bound OX40L in patients with ACS. Enhanced level of serum PAPP-A and sOX40L might represent a prognostic marker for coronary disease activity.

Innate signals from Nod2 block respiratory tolerance and program T(H)2-driven allergic inflammation.

BACKGROUND: Airway tolerance is critical for protecting the lung from inflammatory disease driven by allergens. However, factors that disrupt tolerance processes and then lead to susceptibility to developing allergic asthma remain elusive. OBJECTIVE: To investigate whether recognition of bacterial microbial-associated molecular patterns in the lung may result in susceptibility to developing allergic reactions, and to understand the molecular mechanisms by which such triggers block natural tolerance. METHODS: Ligands of intracellular microbial-associated molecular pattern recognition receptors-the nucleotide-binding oligomerization domain (Nod)-like receptors, Nod1 and Nod2-were given intranasally with antigen, and their ability to modulate airway tolerance was analyzed. RESULTS: Intranasal Nod2 ligand rapidly induced lung expression of the innate cytokines thymic stromal lymphopoietin and IL-25, and thymic stromal lymphopoietin promoted expression of OX40 ligand, a T-cell-costimulatory ligand, on lung CD11c(+)CD11b(+) cells and B220(+) cells. Together these 3 molecules blocked the generation of antigen-specific CD4(+)forkhead box protein 3(+) adaptive regulatory T cells and concomitantly drove IL-4-producing CD4 T cells. By altering the regulatory T/T(H)2-cell balance, tolerance was blocked, and sensing of Nod2 ligand resulted in subsequent susceptibility to developing eosinophil-dominated airway inflammation. CONCLUSION: We show that a Nod-like receptor is a novel, previously unrecognized, pathway that adversely links innate and adaptive immunity and leads to allergic disease and asthmatic lung inflammation.

Diesel exhaust particle-treated human bronchial epithelial cells upregulate Jagged-1 and OX40 ligand in myeloid dendritic cells via thymic stromal lymphopoietin.

Ambient particulate matter, including diesel exhaust particles (DEP), promotes the development of allergic disorders. DEP increase oxidative stress and influence human bronchial epithelial cell (HBEC)-dendritic cell interactions via cytokines, including thymic stromal lymphopoietin (TSLP). Upregulation of TSLP results in Th2 responses. Using primary culture HBEC and human myeloid dendritic cell (mDC) cocultures, we show in this study that DEP upregulation of Th2 responses occurred via HBEC-dependent mechanisms that resulted from oxidative stress. Moreover, DEP-treated HBEC and ambient particulate matter-treated HBEC upregulated OX40 ligand (OX40L) and the Notch ligand Jagged-1 mRNA and expression on mDC. Upregulation of OX40L as well as Jagged-1 on mDC required HBEC and did not occur in the presence of N-acetylcysteine. Furthermore, OX40L and Jagged-1 upregulation was inhibited when HBEC expression of TSLP was silenced. Thus, DEP treatment of HBEC targeted two distinct pathways in mDC that were downstream of TSLP expression. Upregulation of OX40L and Jagged-1 by mDC resulted in mDC-driven Th2 responses. These studies expand our understanding of the mechanism by which ambient pollutants alter mucosal immunity and promote disorders such as asthma.

T-cell polarization depends on concentration of the danger signal used to activate dendritic cells.

Although several studies have focused on allergic sensitization by dendritic cells, to date it is still open under which conditions these antigen-presenting cells are able to induce an allergic immune response. Our study reveals that BMDCs pulsed with LPS-free ovalbumine did not induce allergic disease. However, when BMDCs were activated with low-dose LPS during pulsing with allergen, these cells expressed an inflammatory set of cytokines and co-stimulatory molecules like CD86 and OX40L. Moreover, activated cells were able to prime mice for massive eosinophilic inflammation of the lung, airway hyper-reactivity, IgE production and production of Th2 cytokines by lymphocytes. Blocking experiments showed that expression of OX40L is not involved in induction of Th2 response. Interestingly, BMDCs that were activated with high dose of LPS lose their Th2-sensitizing capacity. Instead these cells induce a Th17 type immune response. We conclude that presentation of allergen by dendritic cells generated with GMCSF is not sufficient to lead to induction of allergic immune response. Further activation of BMDCs is required to prime mice for allergic immune response. In this study, we show that LPS is a suitable stimulus. However, when cells were activated with high dose LPS they tended to induce a Th17 response.

Expression and function of the inducible costimulator ligand B7-H2 in human airway smooth muscle cells.

BACKGROUND: B7-H2 is a ligand for the inducible costimulator (ICOS). The aim of this study was to examine the expression and function of B7-H2 in human airway smooth muscle (ASM) cells and compare them with those of CD40 or OX40 ligand (OX40L). METHODS: Expression of B7-H2, CD40 and OX40L in ASM cells and their respective counterparts in T cells was analyzed by RT-PCR or flow cytometry. The modulating effect of polyinosinic-polycytidylic acid (poly I:C) on expression of B7-H2, CD40 and OX40L was also examined. The function of these three molecules was evaluated by virtue of adhesion of anti-CD3-activated T cells, IL-6 and IL-8 production and DNA synthesis. RESULTS: ASM cells constitutively expressed B7-H2, CD40 and OX40L that mediated adhesion of activated T cells expressing ICOS, CD40L and OX40. ASM cells responded to poly I:C with upregulated expression of B7-H2, CD40 and OX40L and displayed enhanced adhesion of activated T cells. Functional analysis performed on untreated ASM cells showed that engagement of B7-H2 with ICOS-Ig clearly induced DNA synthesis, whereas that of CD40 or OX40L with trimeric CD40L or OX40-Ig greatly increased IL-6 and IL-8 production. These responses were enhanced in poly I:C-treated ASM cells. CONCLUSIONS: The data demonstrate that ASM cells express functionally active B7-H2, CD40 and OX40L and suggest that B7-H2-dependent signaling may play an active role in a proliferative response rather than in cytokine and chemokine production. In addition, the modulation of B7-H2, CD40 and OX40L expression and function by poly I:C may have important implications for the function of virus-infected ASM cells.

Upregulation of OX40-OX40 ligand system on T lymphocytes in patients with acute coronary syndromes.

OBJECTIVE: To investigate whether upregulation of OX40-OX40 ligand (OX40L) system is related to stability of coronary atherosclerotic plaque in patients with coronary heart diseases. METHODS: Thirty normal controls and 250 patients, including 80 with stable angina (SA), 110 with unstable angina (UA), and 60 with acute myocardial infarction (AMI), were enrolled in our study. The expression of OX40 and OX40L in peripheral CD4 T lymphocytes were analyzed by flow cytometry. Serum soluble OX40L (sOX40L) and C-reactive protein levels were measured by commercially available enzyme-linked immunosorbent assay kit. RESULTS: The expression of OX40 and OX40L in peripheral CD4 T lymphocytes in patients with UA [26.7 +/- 3.4 and 45.5 +/- 8.1 mean fluorescence intensity (MFI)] and AMI (27.4 +/- 4.6 and 55.7 +/- 9.4 MFI) were significantly higher than those in patients with SA (6.5 +/- 1.4 and 12.4 +/- 3.2 MFI) and controls (7.3 +/- 1.5 and 11.9 +/- 6.1 MFI). sOX40L in patients with UA (38.7 +/- 6.9 ng/mL) and AMI (39.5 +/- 7.3 ng/mL) were significantly higher than those in patients with SA (8.4 +/- 1.4 ng/mL) (P < 0.01) and controls (8.9 +/- 2.3 ng/mL) (P < 0.01). C-reactive protein level in serum in patients with UA (14.6 +/- 3.3 ng/mL) and AMI (15.0 +/- 4.3 ng/mL) were also higher than those in patients with SA (1.4 +/- 0.4 ng/mL) and controls (1.3 +/- 0.3 ng/mL). It was interesting that there was a peak level of sOX40L at 12 hours after AMI in patients with AMI. A positive correlation was found between sOX40L and serum C-reactive protein levels (r = 0.71; P < 0.0001). CONCLUSIONS: Patients with acute coronary syndromes showed increased coexpression of OX40 system, which may create a proinflammatory and prothrombotic milieu for aggravating the development of atherosclerosis and instability of atherosclerotic plaques, and sOX40L is a potential marker for predicting the severity of coronary heart diseases.

Decreased 4-1BB expression on HIV-specific CD4+ T cells is associated with sustained viral replication and reduced IL-2 production.

CD4+ T cell dysfunction in subjects with chronic HIV infection is in part due to an imbalance of costimulatory and coinhibitory receptors. We report that virus-specific CD4+ T cells expressing 4-1BB (CD137) or OX40 (CD134) produced more IL-2 than cells lacking these costimulatory receptors (P<0.05) and that 4-1BB was expressed at a lower level on HIV- than CMV-specific IFN-gamma and IL-2 producing CD4+ T cells (P<0.0001 and P<0.01, respectively). Suppression of viral replication with antiretroviral therapy was associated with increased 4-1BB expression on HIV- and CMV-specific IL-2 producing CD4+ T cells (P<0.05 and P<0.01, respectively) and the percentage of IL-2 producing HIV-specific CD4+ T cells that expressed 4-1BB was inversely correlated with HIV plasma viral load (r=-0.75, P=0.007). These findings indicate that the loss of 4-1BB on HIV-specific CD4+ T cells is associated with viral replication and that it may contribute to reduced IL-2 production observed during chronic infection.