IL-27 in combination with anti-PD-1 can be anti-cancer or pro-cancer.

Interleukin-27 (IL-27) is known to play opposing roles in immunology. The present paper considers, specifically, the role IL-27 plays in cancer immunotherapy when combined with immune checkpoint inhibitor anti-PD-1. We first develop a mathematical model for this combination therapy, by a system of Partial Differential Equations, and show agreement with experimental results in mice injected with melanoma cells. We then proceed to simulate tumor volume with IL-27 injection at a variable dose F and anti-PD-1 at a variable dose g. We show that in some range of "small" values of g, as f increases tumor volume decreases as long as fFc(g), where Fc(g) is a monotone increasing function of g. This demonstrates that IL-27 can be both anti-cancer and pro-cancer, depending on the ranges of both anti-PD-1 and IL-27.

IL-27 induces an IFN-like signature in murine macrophages which in turn modulate colonic epithelium.

Mucosal delivery of IL-27 has been shown to have a therapeutic benefit in murine models of inflammatory bowel disease (IBD). The IL-27 effect was associated with phosphorylated STAT1 (pSTAT1), a product of IL27 receptor signaling, in bowel tissue. To determine whether IL-27 acted directly on colonic epithelium, murine colonoids and primary intact colonic crypts were shown to be unresponsive to IL-27 in vitro and to lack detectable IL-27 receptors. On the other hand, macrophages, which are present in inflamed colon tissue, were responsive to IL-27 in vitro. IL-27 induced pSTAT1 in macrophages, the transcriptome indicated an IFN-like signature, and supernatants induced pSTAT1 in colonoids. IL-27 induced anti-viral activity in macrophages and MHC Class II induction. We conclude that the effects of mucosal delivery of IL-27 in murine IBD are in part based on the known effects of IL27 inducing immunosuppression of T cells mediated by IL-10. We also conclude that IL-27 has potent effects on macrophages in inflamed colon tissue, generating mediators that in turn act on colonic epithelium.

Clinical value of serum IL-27 in allergic rhinitis patients and its relationship with Treg associated cytokine levels.

Allergic rhinitis (AR) is a nasal allergic disease mainly mediated by IgE, and the immune response is the pathological basis of AR pathogenesis. Regulatory T cells (Treg) has been confirmed to be involved in the occurrence of AR. IL-27 mediates inflammatory responses and allergic symptoms in AR by promoting Tregs and related factors. Our study aimed to explore the correlation between serum interleukin 27 (IL-27) and Treg associated cytokines in the pathogenesis of AR. Based on the inclusion and exclusion criteria, 69 participants with AR and 50 healthy participants were selected. Their IL-27, IL-10, and TGF-ß1 levels were estimated by ELISA. Receiver operating characteristics curve (ROC) was performed to demonstrate the diagnostic efficiency of IL-27 in AR. Pearson correlation analysis was used for correlation analysis. IL-27 in AR patients statistically decreased compared to the control group. Consistently, IL-27 were also negatively correlated with the clinical severity of AR patients. Treg related cytokines including IL-10 and TGF-ß1 in AR patients was statistically decreased. In addition, the IL-10 and TGF-ß1expressions were positively correlated with IL-27 in AR patients. IL-27 was statistically down-regulated in patients with AR, which is related to insufficient Treg function. Restoring the expression of IL-27 may become a novel approach to treat AR.

IL-27 regulates autophagy in rheumatoid arthritis fibroblast-like synoviocytes via STAT3 signaling.

Rheumatoid arthritis (RA) is a highly prevalent autoimmune condition associated with pronounced synovial inflammation. The majority of RA patients required long-term treatment to control disease progression, thus imposing a significant financial burden on affected individuals. The development of RA is critically influenced by fibroblast-like synoviocytes (FLSs) within the synovial lining. IL-27 is an IL-6/IL-12 family cytokine that has recently been shown to play varied pro-inflammatory or protective roles in particular autoimmune diseases. However, the effects of IL-27 on FLSs in the context of RA have yet to be clarified and warrant further research. This study was developed to evaluate the impact of IL-27 treatment on apoptotic and autophagic activity in RA-associated FLSs, with a particular focus on the role of the STAT3 pathway in this regulatory context. Through these experiments, we found that IL-27 was able to suppress FLS proliferation and autophagic activity, with a high dose of this cytokine (100 ng/mL) markedly suppressing autophagy while simultaneously inducing some level of cellular apoptosis. The STAT3 inhibitor STA21 was found to reverse the IL-27-mediated suppression of autophagic activity in these RA-associated FLSs. Imbalanced cellular proliferation and apoptosis is of critical importance in the context of RA progression, and we found that IL-27 was able to regulate such imbalance and to enhance the apoptotic activity of RA FLSs by inhibiting rapamycin-activated autophagy. Together, these results indicate that IL-27 can regulate autophagic activity within RA-associated FLSs via the STAT3 signaling pathway, leading to inhibition of cellular proliferation.

CCR1 antagonist J-113863 corrects the imbalance of pro- and anti-inflammatory cytokines in a SJL/J mouse model of relapsing-remitting multiple sclerosis.

Multiple sclerosis (MS), an immune-mediated and neurodegenerative disorder of the central nervous system (CNS), is characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model used to study MS. To explore the impact of chemokine receptor CCR1 blockade in EAE and the underlying mechanisms, we used CCR1 antagonist J-113863 in PLP139-151-induced EAE in SJL/J mice. Following EAE induction, mice were treated with J-113863 (10 mg/kg) daily from day 14 until day 25. We investigated the effect of J-113863 on expression levels of GM-CSF, IL-6, IL-10, IL-27 in CD4+ spleen cells, using flow cytometry. We also analyzed the effect of J-113863 on GM-CSF, IL-6, IL-10, IL-27 mRNA and protein expression levels using RT-PCR and Western blot analysis in brain tissues. J-113863 treatment decreased the populations of CD4+GM-CSF+ and CD4+IL-6+ cells and increased CD4+IL-27+ and CD4+IL-10+ cells in the spleen. J-113863 had a suppressive effect on the mRNA and protein expression levels of GM-CSF, and IL-6 in the brain tissue. On the other hand, J-113863 treatment increased the mRNA and protein expression of IL-10 and IL-27 in the brain tissue. Our results highlighted J-113863's potential role in suppressing pro-inflammatory expression and up-regulating anti-inflammatory mediators, which could represent a beneficial alternative approach to MS treatment.

IL-27 overexpression alleviates inflammatory response in allergic asthma by inhibiting Th9 differentiation and regulating Th1/Th2 balance.

OBJECTIVE: To investigate the effect of IL-27 on Th9 differentiation and Th1/Th2 balance. METHODS: C57BL/6 (B6) mice were treated with ovalbumin to establish an allergic asthma (AA) model and subjected to IL-27 overexpression (OV) and empty vector (EV). Hematoxylin-eosin (HE) staining was performed to observe lung tissue inflammation. Flow cytometry was carried out to evaluate the percentage of Th9, Th1, and Th2 cells. The expression of IL-27, IL-27R, IL-9, T-bet, IFN-γ, and IgE was evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Western blot was conducted to observe the expression of pSTAT-1 and pSTAT-3. RESULTS: Compared with the Model group, the number of Th1 cells in the Model + OV group increased significantly (p < .05), while those of Th9 and Th2 cells decreased significantly (p < .05). The expression of IL-27, IL-27R, and IFN-γ in blood serum was increased (p < .05), and that of IL-9 and IgE was significantly decreased in the Model + OV group compared to the Model (p < .05). Western blot revealed that Model + OV exhibited lower expression of pSTAT-3 than that in the Model and Model + EV groups (p < .05), while pSTAT-1 expression was significantly increased (p < .05). Inflammatory infiltration in the Model + OV group was significantly reduced, and there was no significant difference between the Model and Model + EV groups. CONCLUSIONS: IL-27 OV inhibits Th9 differentiation and regulates the imbalance of Th1/Th2, thereby alleviating inflammatory response in AA. The findings suggest that IL-27 OV may be a potential strategy for clinical treatment of AA.

IL-27 Improves Prophylactic Protection Provided by a Dead Tumor Cell Vaccine in a Mouse Melanoma Model.

The protocol used to induce cell death for generating vaccines from whole tumor cells is a critical consideration that impacts vaccine efficacy. Here we compared how different protocols used to induce cell death impacted protection provided by a prophylactic whole tumor cell vaccine in a mouse melanoma model. We found that melanoma cells exposed to γ-irradiation or lysis combined with UV-irradiation (LyUV) provided better protection against tumor challenge than lysis only or cells exposed to UV-irradiation. Furthermore, we found that the immunoregulatory cytokine, IL-27 enhanced protection against tumor growth in a dose-dependent manner when combined with either LyUV or γ-irradiated whole tumor cell vaccine preparations. Taken together, this data supports the use of LyUV as a potential protocol for developing whole tumor cell prophylactic cancer vaccines. We also showed that IL-27 can be used at low doses as a potent adjuvant in combination with LyUV or γ-irradiation treated cancer cells to improve the protection provided by a prophylactic cancer vaccine in a mouse melanoma model.

The impact of HCV eradication on hyperglycemia, insulin resistance, cytokine production, and insulin receptor substrate-1 and 2 expression in patients with HCV infection.

Virological responses after hepatitis C virus (HCV) treatment may alleviate liver disease and extra-hepatic manifestations. Our study aims to explore the impact of HCV eradication on the glycemic status, insulin resistance, cytokine production, and insulin receptor substrate (IRS)-1 and 2 gene expression levels in HCV-hyperglycemic patients. A total of 90 participants were allocated as follows: Group 1 included 30 healthy subjects as controls, and Group 2 included 60 HCV-hyperglycemic patients treated with a direct-acting antiviral (DAA) regimen and further subdivided into HCV-pre-diabetic and HCV-diabetic groups. Laboratory assays screened patients before and after treatments. Our data showed an excellent rate of virological responses in HCV groups after HCV treatment. Moreover, HCV eradication significantly ameliorated blood glucose levels and insulin resistance biomarkers in HCV-hyperglycemic patients compared with baseline values. Also, interleukin (IL)-6, IL-17, IL-23, and IL-27 levels were significantly ameliorated after viral clearance in HCV-hyperglycemic patients compared with baseline values. Similarly, IRS-1 and 2 mRNA expression levels were upregulated in these patients post-HCV treatment compared with baseline values. HCV clearance ameliorated hyperglycemia, cytokine production, and enhanced insulin sensitivity. Future researches will be needed to explore the effects of cytokines and IRS on HCV infection and treatment on a large cohort.

IL-27 signalling promotes adipocyte thermogenesis and energy expenditure.

Thermogenesis in brown and beige adipose tissue has important roles in maintaining body temperature and countering the development of metabolic disorders such as obesity and type 2 diabetes1,2. Although much is known about commitment and activation of brown and beige adipose tissue, its multiple and abundant immunological factors have not been well characterized3-6. Here we define a critical role of IL-27-IL-27Rα signalling in improving thermogenesis, protecting against diet-induced obesity and ameliorating insulin resistance. Mechanistic studies demonstrate that IL-27 directly targets adipocytes, activating p38 MAPK-PGC-1α signalling and stimulating the production of UCP1. Notably, therapeutic administration of IL-27 ameliorated metabolic morbidities in well-established mouse models of obesity. Consistently, individuals with obesity show significantly decreased levels of serum IL-27, which can be restored after bariatric surgery. Collectively, these findings show that IL-27 has an important role in orchestrating metabolic programs, and is a highly promising target for anti-obesity immunotherapy.

Cutting Edge: Steroid Responsiveness in Foxp3+ Regulatory T Cells Determines Steroid Sensitivity during Allergic Airway Inflammation in Mice.

Glucocorticoids are a highly effective first-line treatment option for many inflammatory diseases, including asthma. Some patients develop a steroid-resistant condition, yet, the cellular and molecular mechanisms underlying steroid resistance remain largely unknown. In this study, we used a murine model of steroid-resistant airway inflammation and report that combining systemic dexamethasone and intranasal IL-27 is able to reverse the inflammation. Foxp3+ regulatory T cells (Tregs) were required during dexamethasone/IL-27 treatment of steroid-resistant allergic inflammation, and importantly, direct stimulation of Tregs via glucocorticoid or IL-27 receptors was essential. Mechanistically, IL-27 stimulation in Tregs enhanced expression of the agonistic glucocorticoid receptor-α isoform. Overexpression of inhibitory glucocorticoid receptor-ß isoform in Tregs alone was sufficient to elicit steroid resistance in a steroid-sensitive allergic inflammation model. Taken together, our results demonstrate for the first time, to our knowledge, that Tregs are instrumental during steroid resistance and that manipulating steroid responsiveness in Tregs may represent a novel strategy to treat steroid refractory asthma.

IL-27 Protects the Brain from Ischemia-Reperfusion Injury via the gp130/STAT3 Signaling Pathway.

The occurrence of ischemia-reperfusion (I/R) injury leads to dysfunction as well as high rates of morbidity and mortality in stroke, and new effective therapeutic strategies for I/R are still needed. We investigated the effect of IL-27 on I/R injury-induced neurological function impairment, cerebral infarction volume and variation in levels of inflammatory factors in mice with middle cerebral artery occlusion (MCAO), as well as concentration of LDH and neuronal apoptosis in a neuron oxygen-glucose deprivation and reperfusion (OGD/R) model mediated by gp130/STAT3 signaling in vitro. Our results indicated that IL-27 could bind to its receptor of gp130 to attenuate the I/R injury-induced impairment function and cerebral infarction volume, and decrease inflammatory cytokines TNF-α, IL-1ß and MCP-1 but increase anti-inflammatory factors IL-10 and TGF-ß in vivo, while inhibiting LDH leakage and neuronal apoptosis through activation of STAT3 to antagonize I/R induction. Our results suggest that IL-27 may protect the brain from I/R injury through the gp130/STAT3 signaling pathway.

IL­27 suppresses airway inflammation, hyperresponsiveness and remodeling via the STAT1 and STAT3 pathways in mice with allergic asthma.

Type 2 cytokine­associated immunity may be involved in the pathogenesis of allergic asthma. Although interleukin 27 (IL­27) has been reported as an initiator and suppressor of T­helper 1 (Th1) and T­helper 2 (Th2) responses, respectively, its effects on the development of asthma remain unclear. In the present study, mice were induced and challenged with ovalbumin and received subsequent intranasal administration of IL­27. Total and differential cell counts were determined from Wright­Giemsa­stained cytospins, whereas the cytokine levels were detected using ELISA. In addition, the expression levels of signal transducer and activator of transcription (STAT) 1, STAT3, GATA­binding protein­3 (GATA3) and T­bet (T­box transcription factor) were analyzed in T cells by western blot analysis. Their corresponding mRNA expression levels were determined by quantitative PCR. Airway remodeling was assessed by conventional pathological techniques. The results indicated that intranasal administration of IL­27 ameliorated airway inflammation and hyperresponsiveness in an acute model of asthma. Furthermore, IL­27 prevented airway remodeling in a chronic model of asthma. Following administration of IL­27, the mRNA expression levels of STAT1 and T­bet were upregulated, while those of GATA3 were downregulated. Moreover, the phosphorylation levels of STAT1 and STAT3 were increased. Taken together, these findings demonstrated that intranasal administration of IL­27 ameliorated Th2­related allergic lung inflammation and remodeling in mouse models of asthma by repairing both the STAT1 and STAT3 pathways.

IL-27 alleviates airway remodeling in a mouse model of asthma via PI3K/Akt pathway.

Purpose: Airway remodeling is one of the features of severe asthma. Previous study shows that IL-27 inhibits airway inflammation in asthmatic mice. However, the role of IL-27 on airway remodeling in OVA-induced asthmatic mice and its possible mechanism remain unclear. Methods: We established an ovalbumin (OVA)-induced asthmatic mice model. IL-27 were preventative administered to OVA-induced asthmatic mice. The total cells in Bronchoalveolar lavage fluid (BALF) and Airway hyperresponsiveness (AHR) were measured. The lung tissues were performed by Hematoxylin and eosin (HE) staining to estimate the pathological changes. Masson staining was used to observe the collagen deposition area. The expression of α-smooth muscle actin (α-SMA) and Type I collagen was measured by immunohistochemistry, western blot, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Additionally, western blot was also used to measure the expression of phosphorylated-Akt (p-Akt) in each group. Results: IL-27 group showed significant inhibitory effect on the α-SMA and Type I collagen. The expression of p-Akt in the tissues of asthma model was increased and inhibited by IL-27. Conclusions: IL-27 can alleviate airway remodeling in OVA-induced asthmatic mice, and the mechanism may relate to PI3K/Akt pathway.

Interleukin-27 Ameliorates Renal Ischemia-Reperfusion Injury through Signal Transducers and Activators of Transcription 3 Signaling Pathway.

BACKGROUND: Acute kidney injury (AKI) is a clinical syndrome characterized by significant morbidity and a high death rate. Interleukin (IL)-27 is a newly described member of the IL-6/IL-12 heterodimeric cytokine family and displays anti-inflammatory and antiapoptotic properties. OBJECTIVES: To determine the effect and mechanism of IL-27 in AKI. METHOD: We used a mouse model of renal ischemia/reperfusion (I/R) injury to investigate whether IL-27 has a therapeutic potential for the treatment of AKI. For the IL-27 administration group, IL-27 protein was injected 1 h before ischemia. Human proximal tubular epithelial cells were exposed to ischemia for 2 h and followed by 2 h of reperfusion (I2h+R2h treatment) used as an in vitro model to investigate the effect of IL-27. RESULTS: Two IL-27 subunits, Epstein-Barr virus gene 3 and p28, were upregulated in kidneys 24 h after I/R. Renal expression of IL-27 receptor subunits (gp130 and WSX-1) was also increased. Treatment with IL-27 reduced structural/functional damages, ameliorated renal inflammation, inhibited the cleaved caspase-3 expression, upregulated antiapoptotic protein Bcl-2 and downregulated proapoptotic protein Bax in the kidneys of mice subjected to I/R. Meanwhile, the level of IL-27 receptor on renal tubular epithelial cells was increased after I2h+R2h treatment, and IL-27 administration suppressed I2h+R2h-induced epithelial cell apoptosis. Furthermore, IL-27 treatment led to activation of signal transducer and activator of transcription 3 (STAT3) both in vivo and in vitro, and IL-27-mediated protection against I2h+R2h injury was abolished by STAT3 inhibition. CONCLUSIONS: IL-27 protects against renal I/R injury by activating STAT3, suggesting that IL-27 may represent a novel strategy for the treatment of AKI.

The Immunobiology of the Interleukin-12 Family: Room for Discovery.

The discovery of interleukin (IL)-6 and its receptor subunits provided a foundation to understand the biology of a group of related cytokines: IL-12, IL-23, and IL-27. These family members utilize shared receptors and cytokine subunits and influence the outcome of cancer, infection, and inflammatory diseases. Consequently, many facets of their biology are being therapeutically targeted. Here, we review the landmark discoveries in this field, the combinatorial biology inherent to this family, and how patient datasets have underscored the critical role of these pathways in human disease. We present significant knowledge gaps, including how similar signals from these cytokines can mediate distinct outcomes, and discuss how a better understanding of the biology of the IL-12 family provides new therapeutic opportunities.

Interleukin 27 (IL-27) Alleviates Bone Loss in Estrogen-deficient Conditions by Induction of Early Growth Response-2 Gene.

A growing understanding of the bone remodeling process suggests that inflammation significantly contributes to the pathogenesis of osteoporosis. T cells and various cytokines contribute majorly to the estrogen deficiency-induced bone loss. Recent studies have identified the IL-12 cytokine family as consisting of pro-inflammatory IL-12 and IL-23 and the anti-inflammatory IL-27 and IL-35 cytokines. IL-27 exerts protective effects in autoimmune diseases like experimental autoimmune encephalomyelitis; however, its role in the pathogenesis of osteoporosis remains to be determined. In this report, we study the effect of IL-27 supplementation on ovariectomized estrogen-deficient mice on various immune and skeletal parameters. IL-27 treatment in ovariectomized mice suppressed Th17 cell differentiation by inhibiting transcription factor RORγt. Supplementation of IL-27 activates Egr-2 to induce IL-10 producing Tr1 cells. IL-27 treatment prevented the loss of trabecular micro-architecture and preserved cortical bone parameters. IL-27 also inhibited osteoblast apoptosis through increased Egr-2 expression, which induces anti-apoptotic factors like MCL-1. IL-27 suppressed osteoclastogenesis in an Egr-2-dependent manner that up-regulates Id2, the repressor of the receptor activator of nuclear factor-κB ligand-mediated osteoclastogenesis. Additionally, these results were corroborated in female osteoporotic subjects where we found decreased serum IL-27 levels along with reduced Egr-2 expression. Our study forms a strong basis for using humanized IL-27 toward the treatment of post-menopausal osteoporosis.

Potent therapeutic target of inflammation, virus and tumor: focus on interleukin-27.

Interleukin (IL)-27 is an important pleiotropic immunological regulator for having dual effects on the immune responses. Several distinct findings have been highlighted that in certain conditions, neutralizing IL-27 or its subunit IL-27p28 might be a useful strategy to limit inflammation. Recently more insights have revealed that IL-27 could also exert potent inhibitory functions in some other immune circumstances including virus infection and tumor immunity. In this review, we describe IL-27 receptor subunits and the mechanisms of individual IL-27, and summarize the advances of their preclinical application trials. In addition, the potential role of IL-27 as a clinical therapeutic target will also be discussed.

Interleukin-27 gene delivery for modifying malignant interactions between prostate tumor and bone.

We have examined the role of a novel cytokine, interleukin-27 (IL-27), in mediating interactions between prostate cancer and bone. IL-27 is the most recently characterized member of the family of heterodimeric IL-12-related cytokines and has shown promise in halting tumor growth and mediating tumor regression in several cancer models, including prostate cancer. Prostate cancer is frequently associated with metastases to the bone, where the tumor induces a vicious cycle of communication with osteoblasts and osteoclasts to induce bone lesions, which are a significant cause of pain and skeletal-related events for patients, including a high fracture risk. We describe our findings in the effects of IL-27 gene delivery on prostate cancer cells, osteoblasts, and osteoclasts at different stages of differentiation. We applied the IL-27 gene delivery protocol in vivo utilizing sonoporation (sonodelivery) with the goal of treating and reducing the growth of prostate cancer at a bone metastatic site in vivo. We used a new model of immune-competent prostate adenocarcinoma and characterized the tumor growth reduction, gene expression, and effector cellular profiles. Our results suggest that IL-27 can be effective in reducing tumor growth, can help normalize bone structure, and can promote enhanced accumulation of effector cells in prostate tumors. These results are promising, because they are relevant to developing a novel IL-27-based strategy that can treat both the tumor and the bone, by using this simple and effective sonodelivery method for treating prostate tumor bone metastases.

Bioengineering heterodimeric cytokines: turning promiscuous proteins into therapeutic agents.

The interleukin 12 (IL-12) family comprises a group of heterodimeric cytokines that can cope with a great variety of immune conditions as the microenvironment demands. By sharing cytokine and receptor subunits, IL-12 (comprised of p40/p35 subunits), IL-23 (p40/p19), IL-27 (p28/EBI3), and IL-35 (p35/EBI3) represent, as a whole, a highly versatile system participating in controlling the continuum from inflammation to tolerance. Promiscuity, a peculiar feature of those cytokines, is a powerful and economic means of producing individual factors with distinct activities via different combinations of a single set of subunits. Whereas IL-12 and IL-23 have a clearly dominant immunostimulatory functional profile and IL-35 is a potent immunosuppressive agent, IL-27 can exert both adjuvant and regulatory effects, depending on the cytokine milieu. Promiscuity itself, however, may significantly hamper the therapeutic use of heterodimeric cytokines. The subunits of a recombinant cytokine, when administered in its native form, will rapidly dissociate in vivo and reassociate with alternative partners, thus generating different heterodimeric or even homodimeric molecules (i.e., p40/p40) with unwanted effects. As in other areas, bioengineering has provided a formidable tool to overcome the constraints associated with the potential use of IL-12 family cytokines. The generation of several gene constructs expressing IL-12, IL-23, IL-27, IL-35, or even the homodimer p40/p40, in their monomerized, single-chain form has allowed us to unveil the efficacy of those molecules in several experimental settings, including neoplasia, viral infection, chronic inflammation, allergy and autoimmunity. Although work is still needed to obtain an overall picture of therapeutic vs. adverse effects of individual molecules before any use in humans, the new frontiers of bioengineering are now driving the production of completely new combinations of cytokine subunits that may further extend the potential clinical use of such eclectic proteins.

Gene therapy using IL-27 ameliorates Sjögren's syndrome-like autoimmune exocrinopathy.

INTRODUCTION: Sjögren's syndrome (SjS) is a systemic autoimmune disease characterized by decreased salivary and lacrimal gland secretions, resulting in severe dry mouth and dry eyes. Recent studies have suggested that TH17 cells and its signature cytokine IL-17 are involved in the underlying pathogenic mechanisms leading to destructive inflammation and autoimmunity. In the present study, we examined whether IL-27, a natural inhibitor of TH17 activity, could down-regulate or reverse SjS in C57BL/6.NOD-Aec1Aec2 mice, a model of primary-SjS. METHODS: Recombinant serotype 2 adeno-associated viral (AAV2) vectors expressing either IL-27 (rAAV2-IL27) or LacZ (rAAV2-LacZ) were injected into 6 or 14 week-old C57BL/6.NOD-Aec1Aec2 mice. Changes in IL-27, IL-17, and IL-10 cytokine levels in peripheral blood were determined by ELISAs, while flow cytometry analyses were used to quantify cytokine-positive splenocytes. Histological assessment of salivary glands, anti-nuclear autoantibody (ANA) staining, and stimulated saliva flow rates were used to profile SjS disease severity. RESULTS: Mice systemically treated with intravenous rAAV2-IL27 injections at either 6 or 14 weeks of age exhibited long-term elevated levels of serum IL-27 with concomitantly reduced levels of IL-17 compared with sera from mice injected with rAAV2-LacZ or saline out to 20 weeks post-inoculation. Most importantly, disease profiles revealed that rAAV2-IL27 treatment had little effect on lymphocytic focus (LF) scores, but resulted in structural changes in LF, lower titers of ANAs with changes in staining patterns, and a less severe clinical disease as determined by saliva flow rates. CONCLUSIONS: These data support the concept that IL-27, when provided exogenously, can induce a suppressive effect on SjS development and thus may be an effective therapeutic agent for regulating TH17 pro-inflammatory activity in autoimmune diseases where the TH17 system has been shown to play an important role in their pathogenesis.