Increased CD69 Expression Research Articles

Whole Blood Profiling of Bacillus Calmette-Guérin-Induced Trained Innate Immunity in Infants Identifies Epidermal Growth Factor, IL-6, Platelet-Derived Growth Factor-AB/BB, and Natural Killer Cell Activation.

Vaccination of infants with bacillus Calmette–Guérin (BCG) activates both the innate and adaptive arms of the immune response. The antimycobacterial effects of these responses most likely account for the ability of BCG to protect against childhood forms of tuberculosis (TB). There is also evidence for a heterologous protective effect of BCG vaccination against TB-unrelated mortality in low birth weight infants. A possible mechanism of action of this effect, the induction of trained innate immunity, has been demonstrated when cells from BCG-vaccinated adults are restimulated in vitro with non-related microbial stimuli. Our aim was to examine an extensive panel of secreted immune biomarkers to characterize the profile of trained innate immunity in infants. Stimulation of whole blood for 48 h was performed 4 months after BCG vaccination, or in control unvaccinated infants. Stimulants were lipopolysaccharide; Pam3Cys (P3C); heat-killed Candida albicans, Staphylococcus aureus, Escherichia coli, and a lysate of Mycobacterium tuberculosis. Culture supernatants were tested for secreted cytokines and chemokines by 42-plex bead array and monocytes and natural killer (NK) cells assessed for expression of activation markers by flow cytometry. BCG-vaccinated infants displayed increases in 11 cytokines and chemokines in response to different non-specific innate immunity stimuli: epidermal growth factor (EGF); eotaxin; IL-6; IL-7; IL-8; IL-10; IL-12p40; monocyte chemotactic protein-3; macrophage inflammatory protein-1α; soluble CD40 ligand and platelet-derived growth factor (PDGF)-AB/BB. Although each stimulant induced a distinct response profile, three analytes, EGF, IL-6, and PDGF-AB/BB, were commonly higher after stimulation with Pam3Cys, C. albicans, and S. aureus. Conversely, certain cytokines such as interferon gamma-inducible protein-10, IL-2, IL-13, IL-17, GM-CSF, and GRO were suppressed in BCG-vaccinated infants, while no increases in TNFα or IL-1β production were detected. We did not observe a concomitant, BCG-associated change in monocyte surface activation markers in response to non-specific stimuli, but we detected a significant increase in CD69 expression on NK cells in response to Pam3Cys. Pam3Cys-induced NK cell activation correlated with the magnitude of IL-12p40 and IL-10 responses to the same stimulant. This study reveals a novel cytokine/chemokine biomarker signature of BCG-induced trained innate immunity in infants and the involvement of NK cells in these responses.

Kidney triglyceride accumulation in the fasted mouse is dependent upon serum free fatty acids

Lipid accumulation is a pathological feature of every type of kidney injury. Despite this striking histological feature, physiological accumulation of lipids in the kidney is poorly understood. We studied whether the accumulation of lipids in the fasted kidney are derived from lipoproteins or NEFAs. With overnight fasting, kidneys accumulated triglyceride, but had reduced levels of ceramide and glycosphingolipid species. Fasting led to a nearly 5-fold increase in kidney uptake of plasma [14C]oleic acid. Increasing circulating NEFAs using a β adrenergic receptor agonist caused a 15-fold greater accumulation of lipid in the kidney, while mice with reduced NEFAs due to adipose tissue deficiency of adipose triglyceride lipase had reduced triglycerides. Cluster of differentiation (Cd)36 mRNA increased 2-fold, and angiopoietin-like 4 (Angptl4), an LPL inhibitor, increased 10-fold. Fasting-induced kidney lipid accumulation was not affected by inhibition of LPL with poloxamer 407 or by use of mice with induced genetic LPL deletion. Despite the increase in CD36 expression with fasting, genetic loss of CD36 did not alter fatty acid uptake or triglyceride accumulation. Our data demonstrate that fasting-induced triglyceride accumulation in the kidney correlates with the plasma concentrations of NEFAs, but is not due to uptake of lipoprotein lipids and does not involve the fatty acid transporter, CD36.

Abstract 622: Cd44 Plays an Important Role in Regulating Heart Failure Induced Lung Vascular Remodeling and Who Type-2 Pulmonary Hypertension

End-stage left ventricular failure or chronic heart failure (CHF) causes severe lung inflammation, vascular remodeling, WHO type-2 pulmonary hypertension, and right ventricular hypertrophy. However, the molecular mechanism of CHF-induced lung inflammation and remodeling is largely unknown. CD44 is a member of the hyaluronate receptor family of cell adhesion molecules, which has been shown to play a selective role in controlling macrophage and lymphocyte migration. Here we demonstrated that end-stage CHF causes a dramatic increase of CD44 expression in heart and lung in human and mice. Histological staining shows that CD44 is predominantly expressed in leukocytes such as macrophages. Flow cytometry analysis further demonstrates that CD44 is predominantly expressed in F4/80 positive macrophages, CD4+, and CD8+ T cells. CD44 expression is dramatically increased in activated T cell subsets. To further determine the physiological role of CD44 in CHF-induced lung remodeling and type-2 pulmonary hypertension, we studied the effect of CD44 blockade on type-2 pulmonary hypertension development in a group of mice with existing moderate left ventricular failure without apparent lung remodeling. Interestingly, we found that blockade CD44 with blocking antibodies (Abs) significantly attenuate the development of lung vascular and interstitial leukocyte infiltration, lung vascular remodeling, fibrosis, and increase of right ventricular hypertrophy. Blockade CD44 signaling also significantly attenuated further decline of left ventricular ejection fraction in mice with existing LV failure. In addition, we demonstrated that induction of T regulatory cells with IL-2 and IL-2 Abs complex significantly attenuated the infiltration of CD44 positive leukocytes in lung tissue, lung vascular remodeling, lung fibrosis, and right ventricular hypertrophy in mice with existing moderate left ventricular failure. Together, these data indicate an important role of CD44 in left ventricular failure-induced lung inflammation, and type-2 pulmonary hypertension, suggesting that inhibition of CD44 may attenuate heart failure progression and type-2 pulmonary hypertension.

Capturing the systemic immune signature of a norovirus infection: an n-of-1 case study within a clinical trial

Background: The infection of a participant with norovirus during the adaptive study of interleukin-2 dose on regulatory T cells in type 1 diabetes (DILT1D) allowed a detailed insight into the cellular and cytokine immune responses to this prevalent gastrointestinal pathogen.Methods: Serial blood, serum and peripheral blood mononuclear cell (PBMC) samples were collected pre-, and post-development of the infection. To differentiate between the immune response to norovirus and to control for the administration of a single dose of aldesleukin (recombinant interleukin-2, rIL-2) alone, samples from five non-infected participants administered similar doses were analysed in parallel.Results: Norovirus infection was self-limited and resolved within 24 hours, with the subsequent development of anti-norovirus antibodies. Serum pro- and anti-inflammatory cytokine levels, including IL-10, peaked during the symptomatic period of infection, coincident with increased frequencies of monocytes and neutrophils. At the same time, the frequency of regulatory CD4+T cell (Treg), effector T cell (Teff) CD4+and CD8+subsets were dynamically reduced, rebounding to baseline levels or above at the next sampling point 24 hours later. NK cells and NKT cells transiently increased CD69 expression and classical monocytes expressed increased levels of CD40, HLA-DR and SIGLEC-1, biomarkers of an interferon response. We also observed activation and mobilisation of Teffs, where increased frequencies of CD69+and Ki-67+effector memory Teffs were followed by the emergence of memory CD8+Teff expressing the mucosal tissue homing markers CD103 and β7 integrin. Treg responses were coincident with the innate cell, Teff and cytokine response. Key Treg molecules FOXP3, CTLA-4, and CD25 were upregulated following infection, alongside an increase in frequency of Tregs with the capacity to home to tissues.Conclusions: The results illustrate the innate, adaptive and counter-regulatory immune responses to norovirus infection. Low-dose IL-2 administration induces many of the Treg responses observed during infection.

Study of CD69 antigen expression and integrity of leukocyte cellular membrane in stored platelet concentrates following irradiation and treatment with Mirasol® PRT System.

Leukocytes in transfused blood components, particularly residual lymphocytes, have been shown to contribute to the occurrence of various adverse reactions. One of the most severe is transfusionassociated graft versus host disease (TA-GvHD) following transfusion of blood components contaminated with immunocompetent T lymphocytes. Irradiation is a routine method for protection against TA-GvHD. According to the literature, some pathogen reduction methods have also been proven effective for the inactivation of T lymphocytes, and so they may be considered as an alternative to irradiation. Comparison of CD69 antigen expression and the integrity of the leukocyte cellular membrane in stored platelet concentrates (PCs) following irradiation with the Gammacell 3000 Elan (Nordion Inc., Ottawa, Canada) and treatment with the Mirasol® Pathogen Reduction Technology (PRT) System (Terumo BCT, Lakewood, USA). The study included seven experiments. For each experiment we used 3 PCs, for Mirasol® PRT System treatment (M), for Gammacell 3000 Elan irradiation (R), and for the control (C). 7-amino-actinomycin D (7-AAD, Becton Dickinson, Franklin Lakes, USA) permeability was used to determine lymphocyte viability while CD69 antigen expression was the marker of lymphocyte activation. Analyses of 7-AAD and CD69 antigen expression were performed in a FACS Canto I flow cytometer (Becton Dickinson, USA). During 6 storage days, viable lymphocyte count decreased to 28% (p = 0.001) in the Mirasol® PRT System treated PCs and to 65% (p = 0.004) in the irradiated PCs. A statistically significant increase in CD69 expression in the irradiated PCs was observed; 1.3-fold on day 3 and 1.5-fold on day 6. In the Mirasol ® PRT System treated PCs, no statistically significant increase was observed. The in vitro results suggest that the Mirasol® PRT System is as effective as irradiation due to donor leukocyte inactivation capacity.

Effect of exogenous interferon-gamma (IFN-gamma) on peripheral blood immune markers as part of a phase I clinical trial of combined IFN-gamma with nivolumab (Nivo) in patients (pts) with select solid tumors.

97 Background: IFN-gamma is a known activator of PD-L1 expression and plays a key role in immune activation. We present initial correlative peripheral blood findings after the first 2 cohorts of pts enrolled in a phase I trial of combined IFN-gamma/Nivo in pts with various solid tumors. Methods: Pts with advanced solid tumors who had progressed after at least 1 prior therapy were recruited. An induction phase of IFN-gamma (50 or 75 mcg/m2 subq every other day for 1 week) preceded the combination of Nivo (3 mg/kg IV every 2 weeks) with continuation of IFN-gamma at same dose and schedule for 3 months. Pts with clinical benefit could remain on Nivo alone for up to 1 year. Peripheral blood was analyzed via flow cytometry at baseline, after IFN-gamma induction (prior to Nivo start), and after 6 weeks of combo treatment. Results: 13 pts have been accrued. Pre and post induction samples were collected on all pts. Nine pts had available on-treatment samples at time of data analysis. Comparing blood collections from baseline to post-IFN-gamma induction revealed a substantial expansion of the CD14high, CD16+ monocyte population (p=0.001) and a statistically significant increase in MHC class II expression on all monocyte populations (p≤ 0.002 for all types). Natural killer (NK) cells demonstrated greater numbers of cells per ml of blood (p=0.03) and increased NKp30 expression, an important receptor mediating tumor cell lysis (p= 0.005 for CD56dim; p= 0.03 for CD56bright). With the addition of Nivo, evidence for activation of CD56dim NK cells was detected as increased CD69 expression compared to post-induction (p=0.02). PD-1 expression on T-cells showed reduced expression in most comparators after initiation of Nivo (p=0.055 CD8+; p=0.008 CD4+). Conclusions: Early correlative peripheral blood data demonstrate expected systemic IFN-gamma effect as measured by monocyte activation and increased MHC II expression. Evidence of NK cell activation and proliferation was also observed. Decreased PD-1 expression on T-cells may reflect down-regulation in response to PD-1 blockade. Correlations with biopsy specimens and clinical response are planned. Clinical trial information: NCT02614456.

Panobinostat Induces Upregulation of CD38 and Augments the Anti-Myeloma Efficacy of Daratumumab in Pre-Clinical Models

Background:Immunotherapy with monoclonal antibodies (mAbs) has recently entered the clinical arena in multiple myeloma, including Daratumumab that targets CD38 on malignant plasma cells. The efficacy of mAbs depends on antigen density and expression of accessory ligands on target cells to initiate cell- and complement-dependent effector mechanisms. Here, we investigate the use of the histone deacetylase inhibitor (HDACi) Panobinostat to modulate target antigen expression and ligand profile on myeloma in favor of potent mAb-mediated recognition and destruction. We show that Panobinostat augments CD38 expression specifically on myeloma cells and demonstrate powerful synergy with anti-CD38 mAb Daratumumab in pre-clinical models.Methods:The myeloma cell line MM1.S and primary myeloma cells were treated with titrated doses of Panobinostat (0, 10, 25 nM) and expression of CD38 and a panel of additional target molecules including B-cell maturation antigen (BCMA) and SLAMF7, as well as accessory ligands analyzed by flow cytometry at 24, 48 and 72 hours. Antibody-dependent cellular cytotoxicity (ADCC) against Panobinostat treated and untreated myeloma cells was analyzed at 4 and 20 hours after addition of PBMC at an effector to target ratio of 25:1 in the presence of Daratumumab (1, 10, 50 ug/mL) or an isotype control antibody.Results:We first treated the myeloma cell line MM1.S with Panobinostat and analyzed its direct cytotoxic anti-myeloma effect. Consistent with previous work, the percentage of live MM1.S myeloma cells had decreased to 85% and 50% after 48 hours of exposure to 10 and 25 nM respectively. We analyzed expression of CD38 on residual live, i.e. 7-AAD negative MM1.S cells by flow cytometry and observed a 1.5 (10 nM) and 2-fold (25 nM) increase of CD38 expression by mean fluorescence intensity (MFI) compared to baseline levels and untreated control cells. The increase in CD38 expression was already detectable after 24 hours and plateaued between 48 and 72 hours. We confirmed our observation in primary myeloma cells from multiple donors (n=4) and detected an even stronger increase to 2 (10 nM) and 4-fold (25 nM) higher CD38 expression compared to untreated cells at 48 hours. Interestingly, expression of BCMA and SLAMF7 was not increased after Panobinostat treatment at all tested concentrations and time points in both MM1.S and primary myeloma. We confirmed that Panobinostat-induced upregulation of CD38 specifically occurred in myeloma, and neither observed this phenomenon in a panel of leukemia and lymphoma cell lines including Raji (Burkitt) and JeKo-1 (mantle cell), nor on resting/activated primary CD8+ and CD4+ T cells that we isolated from peripheral blood of several donors (n=3).Next, we were interested in determining whether the increase in CD38 expression enabled superior anti-myeloma activity of the anti-CD38 mAb Daratumumab. Panobinostat pre-treatment was done for 48 hours at 10 nM as this is a clinically achievable serum level with currently approved regimens. Indeed, significantly higher ADCC was mediated by Daratumumab at all tested concentrations (1, 10 and 50 ug/mL) against MM1.S that we had exposed to Panobinostat. At 4 hours, ADCC was 45% and 25% in Panobinostat-treated and untreated MM1.S respectively, and at 20 hours, near-complete, >90% ADCC of Panobinostat-pre-treated MM1.S had occurred, whereas only 65% of MM1.S were eliminated by Daratumumab without Panobinostat pre-treatment. These data were confirmed in multiple experiments with MM1.S and PBMC from different donors, and with primary myeloma cells. Experiments to evaluate synergy of Panobinostat and Daratumumab therapy in a xenograft model (NSG/MM1.S) are ongoing.Conclusions:Our data demonstrate that the HDACi Panobinostat induces upregulation of CD38 on myeloma and a subsequent dramatic increase of Daratumumab-mediated ADCC in pre-clinical models. These data suggest that Panobinostat could be used synergistically with Daratumumab in a clinical setting to increase response rates and extend duration of responses to Daratumumab. Panobinostat has a known ability to modulate the transcriptional profile of myeloma cells and our data demonstrate for the first time that this ability can be utilized to augment the therapeutic index of antibody-based immunotherapy in multiple myeloma. DisclosuresPallaud:Novartis: Employment. Lehmann:Novartis: Employment. Hudecek:Novartis: Research Funding.

Water-soluble egg membrane enhances the immunoactivating properties of an Aloe vera-based extract of Nerium oleander leaves.

ObjectiveTo evaluate a blend of two natural ingredients on immune parameters relevant for their current topical use and potential support of microcirculation in skin tissue.Materials and methodsA blend (BL) of Aloe vera-based Nerium oleander extract (NAE-8i, oleandrin-free) and hydrolyzed water-soluble egg membrane (WSEM) was applied to human whole-blood cultures for 24 hours, with each separate ingredient serving as a control. Immune-cell subsets were analyzed for expression levels of the activation markers CD69 and CD25. Culture supernatants were analyzed for cytokines, chemokines, and immunoregulating peptides.ResultsBL increased CD69 expression on lymphocytes, monocytes, and CD3–CD56+ natural killer cells, and CD25 expression on natural killer cells. The number of CD69+CD25+ lymphocytes increased in cultures treated with BL and the separate ingredients. BL triggered production of multiple cytokines and chemokines, where CC chemokines MIP1α and MIP3α, as well as cytokines involved in wound healing – Groα, Groβ, ENA78, and fractalkine – reached levels manyfold above treatment with either NAE-8i or WSEM alone.ConclusionData on BL showed that WSEM strongly enhanced NAE-8i’s effects on immunoactivation in vitro. This has potential relevance for support of immunity in skin tissue, including antibacterial and antiviral defense mechanisms, wrinkle reduction, and wound care.

Recombinant human lactoferrin modulates human PBMC derived macrophage responses to BCG and LPS

Lactoferrin, an iron-binding glycoprotein found in mammalian mucosal secretions and granules of neutrophils, possesses several immune modulatory properties. Published reports indicate that lactoferrin enhances the efficacy of the tuberculosis vaccine, BCG (Bacillus Calmette Guerin), both by increasing macrophage and dendritic cell ability to stimulate receptive T cells and by modulating the inflammatory response. This report is the first to demonstrate the effects of a recombinant human lactoferrin (10 μg/mL) on human PBMC derived CD14+ and CD16+ macrophages stimulated with a strong (LPS, 10 ng/mL) or weaker (BCG, MOI 1:1) stimulator of inflammation. After 3 days culture, LPS and human lactoferrin treated CD14+ cells significantly increased production of IL-10, IL-6, and MCP-1 compared to the LPS only group. In contrast, similarly treated CD16+ macrophages increased production of IL-12p40 and IL-10 and decreased TNF-α. Limited changes were observed in BCG stimulated CD14+ and CD16+ macrophages with and without lactoferrin. Analysis of surface expression of antigen presentation and co-stimulatory molecules demonstrated that CD14+ macrophages, when stimulated with BCG or LPS and cultured with lactoferrin, increased expression of CD86. CD16+ macrophages treated with lactoferrin showed a similar trend of increase in CD86 expression, but only when stimulated with BCG.

Increased CD69 Expression on Peripheral Eosinophils from Patients with Food Protein-Induced Enterocolitis Syndrome

Background: Food protein-induced enterocolitis syndrome (FPIES) is an uncommon, non-IgE-mediated food allergy. We recently described a significant increase in fecal eosinophil-derived neurotoxin (EDN) after ingestion of the causative food. However, little is known about the activation status of circulating eosinophils in patients with an acute FPIES reaction. Methods: Surface CD69 expression was assessed by flow cytometry on peripheral eosinophils from 5 patients with FPIES before and after ingestion of the causative food. Fecal EDN was measured by enzyme-linked immunosorbent assay. Results: No eosinophil activation was observed before ingestion; however, a significant increase in CD69 expression on eosinophils after an acute FIPES reaction was demonstrated in all of the patients. There was no significant change in absolute eosinophil counts in the peripheral blood. The levels of fecal EDN increased on the day after ingestion of the causative food in all patients. Conclusion: These results suggest that circulating eosinophils as well as eosinophils in the intestinal mucosal tissue are activated in acute FPIES reactions and might be associated with systemic immune events in FPIES.

Fuzheng Qingjie Granules Inhibit Growth of Hepatoma Cells via Inducing Mitochondria-Mediated Apoptosis and Enhancing Immune Function.

Fuzheng Qingjie (FZQJ) granules, a compound Chinese medicine, have been used as an adjuvant therapy for alimentary tract cancers. However, the underlying anticancer mechanisms are still not well understood. In the present study, HepG2 cells were treated with FZQJ-containing serum. Cell proliferation was evaluated using MTT assay. Apoptosis was analyzed using a flow cytometer. Cell ultrastructure was observed under a transmission electron microscope. The mitochondrial membrane potential (Δψ) was examined with JC-1 dye. In H22 tumor–bearing mice, CD4+ T cells, CD8+ T cells, CD3+ T cells, and natural killer (NK) cells in peripheral blood were evaluated cytometrically. Interleukin (IL)-2 and tumor necrosis factor (TNF)-α levels were measured using radioimmunoassay.The mRNA levels of Bax and Bcl-2 were examined by reverse transcription–polymerase chain reaction. The protein levels of Bax, Bcl-2, cytochrome C, caspase 3 and 9, PARP, and CD69 were examined by Western blotting. The apoptotic cells in tissues were observed using TUNEL method. Alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN), and creatinine (CRE) were detected by an automatic biochemical analyzer. The results showed that FZQJ-containing serum remarkably inhibited proliferation of HepG2 cells in dose- and time-dependent manners, induced HepG2 cell apoptosis and caused a decrease of Δψ. Analysis of tumor tissue showed that FZQJ-induced apoptosis was accompanied by downregulation of Bcl-2 and upregulation of Bax, release of cytochrome c, activation of caspase 3 and 9, and cleavage of PARP. In addition, FZQJ increased the percentages of CD4+ T and NK cells, the ratio of CD4+/CD8+ T cells as well as the levels of serum TNF-α. FZQJ also increased CD69 expression in tumor tissue. No hepatorenal toxicity was observed in H22 tumor–bearing mice. These results indicated that FZQJ could inhibit the growth of hepatoma cells via regulating immune function and inducing mitochondria mediated apoptosis.

Impact of oral meloxicam and long-distance transport on cell-mediated and humoral immune responses in feedlot steers receiving modified live BVDV booster vaccination on arrival

The objective of this study was to investigate the impact of oral meloxicam (MEL) and long-distance transportation on cell-mediated immunity (CMI) in preconditioned steers receiving a booster vaccination on arrival. We hypothesized that steers treated with MEL at 1mg/kg body weight, 6h before night-time transport, would be less immunocompromised on arrival (day 0) and after 7days, and that CMI following vaccination with a modified live bovine viral diarrhea virus (BVDV) recall antigen would be increased. Brahman crossbreed steers, 13–17 months of age (n=87), were randomly assigned to one of four treatment groups: MEL, transported (MTR) (n=22), MEL, non-transported (MNT) (n=22), lactose placebo, transported (CTR) (n=21), and lactose placebo, non-transported (CNT) (n=22). MTR and CTR steers were transported for approximately 16h non-stop on a truck from Mississippi to Iowa (approximately 1300km), whereas steers in the MNT and CNT groups remained in Mississippi as non-transported controls. Body weight was measured and jugular blood was collected at −1, 0, and 7days from all steers at the same time, regardless of location. Multi-parameter flow cytometry (MP-FCM) was used to identify T-cell subsets and detect the expression of three activation markers (CD25 [interleukin (IL)-2 receptor], intracellular interferon-gamma [IFNγ], and IL-4) after in vitro stimulation with BVDV recall antigen. Plasma cortisol concentration was measured on day −1, 0, and 7 as a marker of transport-associated stress. Serum antibody titer to BVDV was assessed on day −1 and day 7 post-booster vaccination. Whole-blood samples were analyzed using MP-FCM on days 0 and 7. Results were log transformed and analyzed using repeated measures of analysis of variance. Compared with non-transported controls, transport led to an increase in BVDV-induced expression of CD25, IFNγ, and IL-4 in CD4+, CD8+, and γδ+ T-cell subsets (P<0.05). MEL treatment mitigated the transportation-associated increase in CD25 expression by peripheral blood mononuclear cells (PBMCs), CD4+, and γδ+ T cells. CMI outputs for the MTR group were less than those of the CTR group (P<0.05); however, the MTR and NT groups did not differ (P>0.10). A treatment*transport interaction was noted for the increase in IL-4 expression by CD8+ T cells after transport, with a significant difference between the CTR and MTR groups at day 7. In conclusion, the use of oral MEL prior to transport appears to have inhibitory or homeostatic effects, but further research is needed to validate the effect of MEL treatment on specific T-cell subsets in transported cattle.

CD40 Negatively Regulates ATP-TLR4-Activated Inflammasome in Microglia.

During acute brain injury and/or sterile inflammation, release of danger-associated molecular patterns (DAMPs) activates pattern recognition receptors (PRRs). Microglial toll-like receptor (TLR)-4 activated by DAMPs potentiates neuroinflammation through inflammasome-induced IL-1β and pathogenic Th17 polarization which critically influences brain injury. TLR4 activation accompanies increased CD40, a cognate costimulatory molecule, involved in microglia-mediated immune responses in the brain. During brain injury, excessive release of extracellular ATP (DAMPs) is involved in promoting the damage. However, the regulatory role of CD40 in microglia during ATP-TLR4-mediated inflammasome activation has never been explored. We report that CD40, in the absence of ATP, synergizes TLR4-induced proinflammatory cytokines but not IL-1β, suggesting that the response is independent of inflammasome. The presence of ATP during TLR4 activation leads to NLRP3 inflammasome activation and caspase-1-mediated IL-1β secretion which was inhibited during CD40 activation, accompanied with inhibition of ERK1/2 and reactive oxygen species (ROS), and elevation in p38 MAPK phosphorylation. Experiments using selective inhibitors prove indispensability of ERK 1/2 and ROS for inflammasome activation. The ATP-TLR4-primed macrophages polarize the immune response toward pathogenic Th17 cells, whereas CD40 activation mediates Th1 response. Exogenous supplementation of IFN-γ (a Th1 cytokine and CD40 inducer) results in decreased IL-1β, suggesting possible feedback loop mechanism of inflammasome inhibition, whereby IFN-γ-mediated increase in CD40 expression and activation suppress neurotoxic inflammasome activation required for Th17 response. Collectively, the findings indicate that CD40 is a novel negative regulator of ATP-TLR4-mediated inflammasome activation in microglia, thus providing a checkpoint to regulate excessive inflammasome activation and Th17 response during DAMP-mediated brain injury.

Immunopotentiation of Different Adjuvants on Humoral and Cellular Immune Responses Induced by HA1-2 Subunit Vaccines of H7N9 Influenza in Mice.

In spring 2013, human infections with a novel avian influenza A (H7N9) virus were reported in China. The number of cases has increased with over 200 mortalities reported to date. However, there is currently no vaccine available for the H7 subtype of influenza A virus. Virus-specific cellular immune responses play a critical role in virus clearance during influenza infection. In this study, we undertook a side-by-side evaluation of two different adjuvants, Salmonella typhimurium flagellin (fliC) and polyethyleneimine (PEI), through intraperitoneal administration to assess their effects on the immunogenicity of the recombinant HA1-2 subunit vaccine of H7N9 influenza. The fusion protein HA1-2-fliC and HA1-2 combined with PEI could induce significantly higher HA1-2-specific IgG and hemagglutination inhibition titers than HA1-2 alone at 12 days post-boost, with superior HA1-2 specific IgG titers in the HA1-2-fliC group compared with the PEI adjuvanted group. The PEI adjuvanted vaccine induced higher IgG1/IgG2a ratio and significantly increased numbers of IFN-γ- and IL-4-producing cells than HA1-2 alone, suggesting a mixed Th1/Th2-type cellular immune response with a Th2 bias. Meanwhile, the HA1-2-fliC induced higher IgG2a and IgG1 levels, which is indicative of a mixed Th1/Th2-type profile. Consistent with this, significant levels, and equal numbers, of IFN-γ- and IL-4-producing cells were detected after HA1-2-fliC vaccination. Moreover, the marked increase in CD69 expression and the proliferative index with the HA1-2-fliC and PEI adjuvanted vaccines indicated that both adjuvanted vaccine candidates effectively induced antigen-specific cellular immune responses. Taken together, our findings indicate that the two adjuvanted vaccine candidates elicit effective and HA1-2-specific humoral and cellular immune responses, offering significant promise for the development of a successful recombinant HA1-2 subunit vaccine for H7N9 influenza.

All-Trans Retinoic Acid and Interferon-Alpha Increase CD38 Expression on Adult T-Cell Leukemia Cells and Sensitize Them to T Cells Bearing Anti-CD38 Chimeric Antigen Receptors

The survival of patients with adult T-cell leukemia (ATL) has been improved by the introduction of anti-CCR4 monoclonal antibody and the expanding use of allogeneic hematopoietic stem cell transplantation. However, not all patients benefit from these treatment modalities, warranting development of a novel therapeutic strategy. CD38, a cell surface ectoenzyme that functions as cyclic ADP ribose hydrolase, is an attractive target of chimeric antigen receptor (CAR) therapy for lymphoid neoplasms because it is widely expressed on the cells of B- or T-lymphoid malignancies. We have previously demonstrated the prominent cytotoxicity of T cells engineered to express an anti-CD38-CAR against B-lymphoma cells and myeloma cells expressing CD38. To expand the applicability of anti-CD38-CAR against ATL cells that usually express undetectable or low levels of CD38, notably, we were successfully able to induce cell surface CD38 expression in HTLV-1-infected cell lines with all-trans retinoic acid (ATRA) (Yoshida T, et al. 2013 ASH Meeting). In ATL cells freshly isolated obtained from the patients, we were able to induce CD38 with ATRA in 60-80% of the cells; the remaining cells survived under the anti-CD38-CAR treatment. We hereby report our attempts in improving the efficacy of anti-CD38-CAR T cells against ATL cells from the patients through the expression of CD38 enhanced with the entry of agents, which are clinically used. Firstly, we investigated whether ATL cells from patients could be transduced with anti-CD38-CAR and what is the efficiency of transduction into T cells in our settings. ATL cells (CD4+ CD25+ GFP+) transduced with retroviral vector were little detected. CD4- CD25- GFP+ T cells alone were detected in our transduction methods. Transduction efficiency was over 40%. To increase the expression of CD38 on ATL cells, we took notice of the CD38 gene upstream region that contains binding sites for interferon regulatory factor-1 (IRF-1) and peroxisome proliferator-activated receptor (PPAR). We thus investigated whether IFN-α, IFN-γ or troglitazone, which is a PPAR-α and -γ agonist, could enhance CD38 expression in ATL cell lines (MT-4, Su9T, ED, and S1T cells), which are negative for CD38. IFN-α and IFN-γ efficiently enhanced CD38 expression in MT-4 cells in a dose-dependent manner but not in Su9T, ED, and S1T cells. As little as 2.5U/ml of IFN-α induced CD38 expression in MT-4 cells for 18 hours in vitr o (>95% at positivity of CD38). 10-25% increase in CD38 expression was observed in ED cells with 125-250 pM troglitazone after 18 hours of treatment, but not in MT-4, Su9T, and S1T cells. Prolonged exposure to troglitazone was toxic to cells. Combined treatment with 10nM ATRA and IFN-α, which induced higher expression of CD38 than IFN-γ, synergistically enhanced CD38 expression of ATL cells from the patients (>90%at positivity of CD38). We next co-cultured ATL cells form three patients with T cells transduced with mock or anti-CD38-CAR in the presence of both ATRA and IFN-α at effector (E): target (T) ratio of 1: 2 for 3 days. The treatment eradicated more than 95% of these ATL cells, demonstrating that ATL cells can be eliminated by T cells harboring anti-CD38-CAR in the presence of ATRA and IFN-α, which is actively used for ATL patients. CD38 targeting therapy is a feasible method, because an anti-CD38 antibody, daratuzumab, has been used to treat plasma cell myeloma. The safety regarding the clinical use of T cells bearing anti-CD38-CAR still needs to be established. As CAR therapy reportedly causes cytokine storm and can potentially be lethal, we envision an inducible immunotherapy with CAR to be a preferred modality with increased efficacy and safety. Our results provide a rationale for a novel therapeutic strategy involving T cells carrying anti-CD38-CAR in combination with ATRA and IFN-α for patients with ATL. DisclosuresNo relevant conflicts of interest to declare.

Anti-Human T-Lymphocyte Immunoglobulin (ATG)-Induced T Regulatory Cells and Their Soluble Factors Suppress T Cell Proliferation: Potential Role in Allogeneic Stem Cell Transplantation

Polyclonal anti-human T-lymphocyte immunoglobulin(ATG) have been recently shown, in two randomized studies, to significantly reduce the incidence of graft versus host disease (GVHD) post allogeneic stem cell transplantation (HSCT) from both sibling and unrelated donors. Induction of regulatory T cells is suggested as one of the possible mechanisms involved. The aim of our current study was to further characterize the T cell populations induced by ATG treatment and to delineate the mechanisms involved in ATG-induced tolerance in patients receiving intravenous ATG (ATG-Fresenius ® S, Neovii Biotech) as part of their pre HSCT conditioning.Phenotypic characterization of regulatory cells markers revealedthattwo days culture of peripheral blood mononuclear cells (PBMCs) with ATG-F (30-120 µg/ml) resulted in significant increase in CD25 expression on CD4+ T cells. The percentages of cells expressing CTLA4, GITR, CD95 and FoxP3 was also significantly elevated on CD4+ cells compared to rabbit IgG-treated PBMCs. In addition, expression of CD127 and VLA-4 molecules was significantly decreased on CD4+CD25+ cells upon ATG-F treatment (p<0.01).Next, tolerance ability of ATG-F-induced cells was examined. Addition of ATG-F-treated cells to autologous PBMCs stimulated with antiCD3/antiCD28 antibodies resulted in significant (50-75%) inhibition of cell proliferation (p<0.001), measured by CFSE and Ki67 staining. Moreover, CD69 cell expression and interferon-γ (IFNγ) proinflammatory cytokine secretion were reduced by 50-60% and 65-90%, respectively, in the presence of ATG-F-activated Treg cells (p<0.01).Importantly, addition of cyclosporine A to the induction culture with ATG-F interfered with the ATG-induced regulatory phenotype acquisition, suggesting the involvement of interleukin-2 in ATG-mediated activity.In order to purify the tolerizing population, sorting of CD4+CD25+CD127-low cells (considered as viable regulatory T cells) from ATG-F-treated culture was performed. Sorted cells demonstrated greater suppressive potency than bulked pre-sorted cell population when added to autologous stimulated PBMCs. Of note, Treg-depleted fraction was still able to suppress the proliferation, albeit less efficiently then sorted Treg cells, suggesting that ATG-F is capable to induce multiple immune suppressive cell populations that should be further defined.To explore the possible involvement of soluble factor(s)-mediated mechanisms, in addition to the involvement of cell to cell contact mechanism, conditioned medium (CM) produced by ATG-F-primed cells was applied on stimulated autologous PBMCs. Addition of CM produced by ATG-F-treated cells, but not IgG-treated cells, resulted in significant suppression (30-65%, p<0.01) of T cell proliferation and activation, indicating the presence of soluble factors secreted by ATG-F-primed suppressive cells. Indeed, significant dose- and time-dependent induction of TGFβ secretion was observed in ATG-treated cells. To this end, addition of TGFβ receptor kinase inhibitor SB-431542 interfered with suppressive activity of ATG-F-primed cells, enabling partial rescue of proliferation and IFNγ secretion in response to antiCD3/antiCD28 activation. Similar results were obtained with anti-TGFβ neutralizing antibodies.Finally, characterization of phenotype and frequencies of regulatory immune populations in peripheral blood of 26 patients undergoing allogeneic transplantation with conditioning regimen including ATG-F (15mg/kg) was performed. Consistent with our ex vivo results, transient increase in percent of circulating CD4+CD25+CD127-low cells was detected in the ATG-F treated patients on days 14, 21 and 28 after HSCT. Furthermore, elevated levels of TGFβ were detected in the patients' plasma at day 28 and remaining high at day 60 post HSCT.Our results demonstratethat in vitro treatment with ATG-F is capableto induce functional Treg cells. Suppressive ability of ATG-F-induced cells was both contact and soluble-factors dependent and was partially promoted by TGFβ. Patients undergoing allogeneic HSCT with ATG-F-including conditioning demonstrated increased frequencies of circulating Treg cells and elevated plasma levels of TGFβ. Altogether, our data further support the use of ATG-F, a potent inducer of Treg cells, for prevention of GVHD post HSCT and potentially other therapeutic applications. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

T cells from patients with Candida sepsis display a suppressive immunophenotype

BackgroundDespite appropriate therapy, Candida bloodstream infections are associated with a mortality rate of approximately 40 %. In animal models, impaired immunity due to T cell exhaustion has been implicated in fungal sepsis mortality. The purpose of this study was to determine potential mechanisms of fungal-induced immunosuppression via immunophenotyping of circulating T lymphocytes from patients with microbiologically documented Candida bloodstream infections.MethodsPatients with blood cultures positive for any Candida species were studied. Non-septic critically ill patients with no evidence of bacterial or fungal infection were controls. T cells were analyzed via flow cytometry for cellular activation and for expression of positive and negative co-stimulatory molecules. Both the percentages of cells expressing particular immunophenotypic markers as well as the geometric mean fluorescence intensity (GMFI), a measure of expression of the number of receptors or ligands per cell, were quantitated.ResultsTwenty-seven patients with Candida bloodstream infections and 16 control patients were studied. Compared to control patients, CD8 T cells from patients with Candidemia had evidence of cellular activation as indicated by increased CD69 expression while CD4 T cells had decreased expression of the major positive co-stimulatory molecule CD28. CD4 and CD8 T cells from patients with Candidemia expressed markers typical of T cell exhaustion as indicated by either increased percentages of or increased MFI for programmed cell death 1 (PD-1) or its ligand (PD-L1).ConclusionsCirculating immune effector cells from patients with Candidemia display an immunophenotype consistent with immunosuppression as evidenced by T cell exhaustion and concomitant downregulation of positive co-stimulatory molecules. These findings may help explain why patients with fungal sepsis have a high mortality despite appropriate antifungal therapy. Development of immunoadjuvants that reverse T cell exhaustion and boost host immunity may offer one way to improve outcome in this highly lethal disorder.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1182-z) contains supplementary material, which is available to authorized users.

Immunomodulatory Effects of Four Leishmania infantum Potentially Excreted/Secreted Proteins on Human Dendritic Cells Differentiation and Maturation

Leishmania parasites and some molecules they secrete are known to modulate innate immune responses through effects on dendritic cells (DCs) and macrophages. Here, we characterized four Leishmania infantum potentially excreted/secreted recombinant proteins (LipESP) identified in our laboratory: Elongation Factor 1 alpha (LiEF-1α), a proteasome regulatory ATPase (LiAAA-ATPase) and two novel proteins with unknown functions, which we termed LiP15 and LiP23, by investigating their effect on in vitro differentiation and maturation of human DCs and on cytokine production by DCs and monocytes. During DCs differentiation, LipESP led to a significant decrease in CD1a. LiP23 and LiEF-1α, induced a decrease of HLA-DR and an increase of CD86 surface expression, respectively. During maturation, an up-regulation of HLA-DR and CD80 was found in response to LiP15, LiP23 and LiAAA-ATPase, while an increase of CD40 expression was only observed in response to LiP15. All LipESP induced an over-expression of CD86 with significant differences between proteins. These proteins also induced significant IL-12p70 levels in immature DCs but not in monocytes. The LipESP-induced IL-12p70 production was significantly enhanced by a co-treatment with IFN-γ in both cell populations. TNF-α and IL-10 were induced in DCs and monocytes with higher levels observed for LiP15 and LiAAA-ATPase. However, LPS-induced cytokine production during DC maturation or in monocyte cultures was significantly down regulated by LipESP co-treatment. Our findings suggest that LipESP strongly interfere with DCs differentiation suggesting a possible involvement in mechanisms established by the parasite for its survival. These proteins also induce DCs maturation by up-regulating several costimulatory molecules and by inducing the production of proinflammatory cytokines, which is a prerequisite for T cell activation. However, the reduced ability of LipESP-stimulated DCs and monocytes to respond to lipopolysaccharide (LPS) that can be observed during human leishmaniasis, suggests that under certain circumstances LipESP may play a role in disease progression.

Adenosine regulates radiation therapy-induced anti-tumor immunity

Radiation therapy (RT) induces immunogenic cell death and dose-dependent release of ATP in the tumor microenvironment (TME), triggering maturation and activation of tumor-resident dendritic cells (DCs). However, extracellular ATP is rapidly catabolized to adenosine by ectonucleotidases CD39 and CD73, which are expressed by tumor cells and immune cells in the TME. Adenosine has pleiotropic immunosuppressive effects and inhibits activation of DC and effector T cells, while promoting regulatory T cells (Tregs). Here, we tested the hypothesis that conversion of ATP to adenosine hinders generation of effective anti-tumor immunity by high dose RT, reducing its synergy with anti-CTLA-4 antibody. BALB/c mice were inoculated s.c. with 1 x 105 TSA carcinoma cells on day 0 and assigned to treatment with: (1) control mAb; (2) anti-CD73 (TY/23); (3) TY/23+anti-CTLA-4 (9H10); (4) RT; (5) RT+TY/23; (6) RT+9H10; (6) RT+TY/23+9H10. TY/23 (200 µg) was administered i.p. every 4 days starting on day 11. RT was given locally as single 20 Gy dose on day 12. 9H10 (200 µg) was given i.p. on days 11, 14 and 17. On day 18, some tumors were harvested for flow cytometry analysis of DC and T cells. Mice were monitored for tumor growth/regression. In irradiated tumors, CD73-blockade reduced the percentage of Tregs within the tumor-infiltrating CD4+ T cell population (7.9±2.5% in RT+TY/23 vs 20±0.8% in RT, p < 0.01) while increasing CD8+T cells (38.3±0.1% in RT+TY/23 vs 17.3±4% in RT, p < 0.05). Among intratumoral DCs (CD11c+MHCII+), the CD8a+ DC subpopulation was increased after CD73-blockade (37.9±15.7% in TY/23+RT vs 11.3±4.9% in RT, p < 0.01). Importantly, in irradiated mice, TY/23-administration enhanced activation of DCs and effector T cells, shown by increased CD40 expression on CD8a+ DCs (MFI: 218±1 in RT+TY/23 vs 54±41 in RT, p < 0.05) and increased CD69 expression on CD8+ T cells (MFI: 513±126 in RT+TY/23 vs 148±59 in RT, p < 0.01). TY/23 and 9H10 given alone or in combination had no effect on tumor growth. However, each antibody potentiated tumor inhibition obtained with RT (p=0.08 for RT+TY/23 and p < 0.05 for RT+9H10 vs RT). Moreover, blockade of both CD73 and CTLA-4 in combination with RT further improved tumor control resulting in complete tumor regression in 2/5 mice (p < 0.01 for RT+TY/23+9H10 vs RT). Our findings indicate that adenosine regulates the ability of RT to induce anti-tumor immunity, affecting both DC maturation and T cell activation. Data suggest that CD73-blockade is a promising strategy to improve synergy of RT and immunotherapy.

Abstract A21: Adenosine is a rheostat for radiation therapy-induced immune activation

Abstract Background: Administration of anti-CTLA-4 antibodies has shown clinical benefit in a small percentage of cancer patients. However, most patients are unresponsive to anti-CTLA-4 antibody treatment, due to immunosuppressive mechanisms and/or the absence of sufficient spontaneous anti-tumor T cells that can be activated by CTLA-4 blockade. We have previously shown that radiotherapy (RT) induces immunogenic tumor cell death and priming of anti-tumor T cells making tumors susceptible to anti-CTLA-4 treatment. RT also triggers the release of ATP in the tumor microenvironment, which has proinflammatory effects. However, ATP is rapidly converted into adenosine, a pleiotropic immunosuppressive mediator, by ectonucleotidases CD39 and CD73 expressed on cancer cells and tumor stromal cells. We hypothesized that adenosine generation in the tumor microenvironment acts as a rheostat modulating RT ability to prime effective anti-tumor immunity. To test this hypothesis we used a mouse tumor model where we have previously characterized two RT regimens that were efficient (8Gy x 3) or inefficient (20 Gy) in inducing anti-tumor immunity in combination with anti-CTLA-4 antibodies. Method: BALB/c mice were inoculated s.c. with 1 x 105 TSA cells, a poorly immunogenic breast cancer cell line on day 0. Anti-CD73 mAb TY/23 (200 µg) was administered i.p. every 4 days starting on day 11. RT was given locally to the tumor as a single 20 Gy dose on day 12 or in three doses of 8 Gy each given on day 12, 13 and 14. At day 19, tumors were harvested and infiltrating immune cells were isolated for analysis of DC and T cell phenotype by flow cytometry. In another experiment, mice were randomly assigned (n=5/group) to be treated with: (1) Isotype control mAb (2) TY/23 (3) TY/23 + anti-CTLA-4 mAb 9H10 (4) RT 20 Gy (5) RT 20 Gy + TY/23 (6) RT 20 Gy + 9H10 (6) RT 20 Gy + TY/23+ 9H10. RT was given on day 12 and mAbs were administered i.p. on day 11, 14, 17 and 20 after tumor inoculation. Mice were monitored for tumor growth. Results: In tumors that had received 8GyX3 RT there was a four-fold increase in CD70 expression (MFI 436 ± 72 in 8GyX3 vs. 110 ± 30 in control, p&amp;lt;0.05) on CD8α+ dendritic cells (DCs), which are responsible for tumor-antigen cross-presentation. In addition, CD8+ T cells showed a two-fold increase in PD-1 expression (MFI 550 ± 22 in 8GyX3 vs. 271 ± 35 in control, p&amp;lt;0.01) and 1.6-fold increase in CD69 expression (MFI 351 ± 95 in 8GyX3 vs. 225 ± 40 in control), indicating increased activation of both DC and T cells in tumors treated with 8GyX3 RT. In contrast, there was no evidence of activation of DC and T cells infiltrating tumors treated with 20Gy RT. However, when 20Gy RT was given in combination with TY/23 to block adenosine generation, DC and T cells showed an increase in expression of activation markers comparable to what was observed in tumors treated with 8GyX3. Interestingly, the frequency of intratumoral CD4+CD25+FoxP3+ regulatory T cells (Treg) was increased in mice receiving TY/23 + 8GyX3 (62% increase, p&amp;lt;0.05) compared to TY/23 alone, suggesting that the inflammation induced by RT may trigger Treg recruitment to the tumor when it is not controlled by adenosine. TY/23 and 9H10 given alone or in combination did not have any effect on tumor growth. However, they improved tumor inhibition obtained with 20 Gy RT (Two-way ANOVA: p=0.08 for RT+anti-CD73 and p&amp;lt;0.05 for RT+9H10 vs. RT alone). Moreover, blockade of both CD73 and CTLA-4 in combination with 20Gy RT further improved tumor control resulting in complete tumor regression in 2/5 mice (p&amp;lt;0.01 for RT+TY/23+9H10 vs. RT alone). Conclusions: Data indicate that the ability of RT to promote immune activation is dependent on the radiation regimen employed and is regulated by adenosine generation by the ectonucleotidase CD73. Importantly, data suggest that blocking CD73 can improve the ability of RT to synergize with immunotherapy. Citation Format: Erik Wennerberg, Noriko Kawashima, Sandra Demaria. Adenosine is a rheostat for radiation therapy-induced immune activation. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A21.