A pilot trial of recombinant human interleukin-10 in kidney transplant recipients receiving OKT3 induction therapy

IL-10 Signaling Elicited by Nivolumab-Induced Activation of the MAP Kinase Pathway Does Not Fully Contribute to Nivolumab-Modulated Heterogeneous T Cell Responses

Immune checkpoint inhibitor (ICI) therapy has revolutionized anti-cancer treatment for many late-stage cancer patients. However, ICI therapy has thus far demonstrated limited efficacy for most patients, and it remains unclear why this is so. Interleukin 10 (IL-10) is a cytokine that has been recognized as a central player in cancer biology with its ability to inhibit anti-tumor T cell responses. Recent studies suggest that IL-10 might also exert some intrinsic anti-tumor T cell responses, and clinical studies using recombinant IL-10 alone or in combination with ICI are underway. This paradoxical effect of IL-10 and its underlying mechanisms impacting ICI-modulated T cell responses remain poorly understood. In this study, using an in vitro mixed lymphocyte reaction assay, we found that treatment with ICIs such as the anti-programmed cell death receptor-1 (PD-1) mAb nivolumab elicits a strong expression of IL-10. While neutralization of IL-10 signaling with an anti-IL-10 specific mAb significantly decreases the production of IFN-γ by T cells in a cohort of donor cells, the opposite effect was observed in other donor cells. Similarly, neutralization of IL-10 signaling significantly decreases the expression of T cell activation markers Ki67 and CD25, as well as the production of Granzyme B in a cohort of donor cells, whereas the opposite effect was observed in others. Furthermore, we found that nivolumab and IL-10 differentially modulate the signal transducer and activator of transcription 3 (STAT3) and AKT serine–threonine kinase pathways. Finally, we found that nivolumab activates the mitogen-activated protein kinase (MAPK) pathway, which in turn is responsible for the observed induction of IL-10 production by nivolumab. These findings provide new insights into the mechanisms underlying anti-PD-1-modulated T cell responses by IL-10, which could lead to the discovery of novel combination treatments that target IL-10 and immune checkpoint molecules.

Regulatory T Cell Therapy Following Liver Transplantation

Liver transplantation (LT) is considered the gold standard of curative treatment for patients with end-stage liver disease or nonresectable hepatic malignant tumors. Rejection after LT is the main nontechnical factor affecting the prognosis of recipients. Medical and surgical advances, combined with improved immunosuppression with drugs such as calcineurin inhibitors (CNIs), have contributed to an increase in 1-year graft survival to around 80%. However, medium- and long-term improvements in LT outcomes have lagged behind. Importantly, CNIs and other classical immunosuppressive drugs are associated with significant adverse effects, including malignancies, cardiovascular disease, and severe renal dysfunction. Immunomodulation using regulatory T cells (Tregs) is emerging as a promising alternative to classical immunosuppression. Since their discovery, the immunomodulatory effects of Tregs have been demonstrated in a range of diseases. This has rejuvenated the interest in using Tregs as a therapeutic strategy to induce immune tolerance after LT. In this review, we first summarize the discovery and development of Tregs. We then review the preclinical data supporting their production, mechanism of action, and therapeutic efficacy followed by a summary of relevant clinical trials. Finally, we discuss the outstanding challenges of Treg therapy and its future prospects for routine use in LT.

The emerging role of regulatory T cells following lung transplantation

Regulatory T cells (Treg) have proven to be a powerful immunologic force in nearly every organ system and hold therapeutic potential for a wide range of diseases. Insights gained from non-transplant pathologies, such as infection, cancer, and autoimmunity, are now being translated to the field of solid organ transplantation, particularly for livers and kidneys. Recent insights from animal models of lung transplantation have established that Tregs play a vital role in suppressing rejection and facilitating tolerance of lung allografts, and such discoveries are being validated in human studies and preclinical trials. Given that long-term outcomes following lung transplantation remain profoundly limited by chronic rejection, Treg therapy holds the potential to significantly improve patient outcomes and should be aggressively investigated.

Fibrosis Related Inflammatory Mediators: Role of the IL-10 Cytokine Family

Importance of chronic fibroproliferative diseases (FDs) including pulmonary fibrosis, chronic kidney diseases, inflammatory bowel disease, and cardiovascular or liver fibrosis is rapidly increasing and they have become a major public health problem. According to some estimates about 45% of all deaths are attributed to FDs in the developed world. Independently of their etiology the common hallmark of FDs is chronic inflammation. Infiltrating immune cells, endothelial, epithelial, and other resident cells of the injured organ release an orchestra of inflammatory mediators, which stimulate the proliferation and excessive extracellular matrix (ECM) production of myofibroblasts, the effector cells of organ fibrosis. Abnormal amount of ECM disturbs the original organ architecture leading to the decline of function. Although our knowledge is rapidly expanding, we still have neither a diagnostic tool to detect nor a drug to specifically target fibrosis. Therefore, there is an urgent need for the more comprehensive understanding of the pathomechanism of fibrosis and development of novel diagnostic and therapeutic strategies. In the present review we provide an overview of the common key mediators of organ fibrosis highlighting the role of interleukin-10 (IL-10) cytokine family members (IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26), which recently came into focus as tissue remodeling-related inflammatory cytokines.

Inflamed gut mucosa: downstream of interleukin-10

BACKGROUND

Interleukin-10 is a pleiotropic cytokine, whose main function is limitation and ultimately termination of immune responses. This is especially true for environmental interfaces such as the gastrointestinal tract. IL-10 acts as a key mediator for maintaining gut homeostasis. IL-10 knockout mice are well established as a genetic model for inflammatory bowel disease (IBD), and sequence variants in the IL-10 locus contribute to ulcerative colitis (UC).

DESIGN

This review covers the significance of IL-10 signalling in the intestinal immune response both in health and disease. It explains the biological role of IL-10, its deregulation in IBD and its contribution to intestinal inflammation via endoplasmic reticulum stress response.

RESULTS

Many IBD susceptibility genes have been discovered in the past years, linking fundamental biological systems, like innate and adaptive immunity, stress responses, autophagy and mucosal barrier to the pathogenesis of Crohn's disease (CD) and UC. IL-10 has long been known for its substantial role in regulating gut immunity, but its contribution to IBD was somewhat elusive. A recent study identified mutations in either IL-10 receptor subunits that are associated with early-onset enterocolitis, a severe phenotype of IBD. Other than genetic variants of IL-10 receptors, IL-10 and STAT3 genes are also associated with IBD, emphasizing the involvement of the IL-10 signalling cascade in the pathogenesis of CD and UC.

CONCLUSIONS

  The discovery of inherited deregulations in the IL-10 signalling cascade is not only considered the missing link between IL-10 and intestinal homeostasis, but also demonstrates how findings made in animal models help explaining human disease.

Interleukin-10 suppresses hepatic TGF-β1 expression and attenuates hepatocyte apoptosis in biliary-obstructed rats

AIM: To explore the effect of interleukin-10 (IL-10) on hepatocyte apoptosis in biliary-obstructed rats.

METHODS: Male Wistar rats were divided randomly into sham operation (SO) group, obstructive jaundice (OJ) group and IL-10 group. Rats of the OJ and IL-10 groups underwent ligation and severing of the common bile duct, while mobilization of the common bile duct was performed in the SO group. The IL-10 group was intraperitoneally injected with IL-10 (4 μg/kg) daily after operation. The mRNA and protein expression of transforming growth factor-β1 (TGF-β1) in liver tissue was detected by fluorescence real-time quantitative PCR and immunohistochemical staining, respectively. Blood samples were taken to measure serum total bilirubin (TBIL), direct bilirubin (DBIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels, while hepatic cell apoptosis was evaluated by TUNEL method.

RESULTS: Compared to the SO group, the levels of serum ALT and AST, hepatic TGF-β1 mRNA and protein expression, and hepatic cell apoptosis index significantly increased in the OJ group 3 days after operation (ALT: 91.83 U/L ± 21.47 U/L vs 47.67 U/L ± 12.79 U/L; AST: 208.67 U/L ± 32.36 U/L vs 75.17 U/L ± 11.96 U/L; TGF-β1 mRNA: 7.48 ± 1.51 vs 1.21 ± 0.79; TGF-β1 protein: 6.11% ± 1.11% vs 1.26% ± 0.64%; apoptosis: 15.06% ± 1.17% vs 3.94% ± 0.46%; all P < 0.05), and further increased 7 d after operation (ALT: 178.83 U/L ± 46.25 U/L vs 44.50 U/L ± 9.97 U/L; AST: 461.17 U/L ± 88.48 U/L vs 76.50 U/L ± 12.39 U/L; TGF-β1 mRNA: 11.98 ± 3.05 vs 1.01 ± 0.52; TGF-β1 protein: 9.97% ± 2.84% vs 1.68% ± 0.71%; apoptosis: 23.49% ± 3.35% vs 4.31% ± 0.67%; all P < 0.05). Treatment with IL-10 significantly decreased hepatic function, hepatic TGF-β1 expression, and hepatic cell apoptosis compared to the OJ group 7 d after operation (ALT: 94.17 U/L ± 20.02 U/L vs 178.83 U/L ± 46.25 U/L; AST: 257.83 U/L ± 56.53 U/L vs 461.17 U/L ± 88.48 U/L; TGF-β1 mRNA: 7.05 ± 1.15 vs 11.98 ± 3.05; TGF-β1 protein: 7.06% ± 1.32% vs 9.97% ± 2.84%; apoptosis: 15.08% ± 1.69% vs 23.49% ± 3.35%; all P < 0.05).

CONCLUSION: IL-10 could attenuate hepatocyte apoptosis by suppressing hepatic TGF-β1 expression in biliary-obstructed rats.

IL-10 secretion increases signal persistence of HEMA-MMA-microencapsulated luciferase-modified CHO fibroblasts in mice

Microencapsulation of cells in a polymer membrane [e.g., poly(hydroxyethyl methacrylate-co-methyl methacrylate) (HEMA-MMA)] has been proposed as a vehicle for the delivery of therapeutic biomolecules, but cells (especially xenogeneic cells) survive only for short times, limiting the utility of this approach. Murine interleukin-10 (mIL-10) has been shown to downregulate the xenogeneic immune response, and we tested the hypothesis that mIL-10 produced by microencapsulated Chinese hamster ovary (CHO) cells would modulate the transplant-site environment leading to prolonged cell function in a xenogeneic model without other immunomodulatory agents. Prior to encapsulation, CHO cells were genetically engineered to express mIL-10 and a firefly bioluminescence protein, luciferase, which allowed for noninvasive tracking of transplanted cells in vivo with the Xenogen IVIS Imaging System. This nondestructive imaging system was sufficiently sensitive to detect photon signal emitted by a single capsule containing around 800 luciferase-transduced CHO (CHO(LUC)) cells in vitro, and to track changes in luciferase expression in vivo over time. Effective modulation of the transplantation-site environment with mIL-10 secreted from capsules was evident by greater luciferase expression at 10 and 21 days after transplantation relative to encapsulated luciferase-transfected cells that did not produce mIL-10. Longer duration effects require further investigation to extend this proof-of-concept study.

Cytoprotective effects of human interleukin-10 gene transfer against necrosis and apoptosis induced by hepatic cold ischemia/reperfusion injury

BACKGROUND

Apoptosis as well as necrosis may play an important role in hepatic ischemia/reperfusion (I/R) injury. Interleukin 10 (IL-10), a Th2 type cytokine, modulates inflammatory responses by inhibiting the production of proinflammatory cytokines. The study focused on cytoprotective and antiapoptotic pathways to assess mechanisms by which gene transduction of human IL-10 (hIL-10) may renders grafts resistant to the cold I/R injury.

MATERIALS AND METHODS

Adenoviruses encoding hIL-10 or beta-galactosidase (LacZ) were injected via the superior mesenteric vein into prospective donor animals. The donor liver was harvested 48h after transduction, and stored for 12h at 4 degrees C lactated Ringer's solution prior to being transplanted. Graft survival, liver function, the degree of necrosis and apoptosis, and the molecules of apoptotic networks were assessed.

RESULTS

Ad-hIL-10 pretreatment significantly prolonged the survival of liver grafts by improving liver function, preserving hepatocyte integrity and architecture, and depressing intrahepatic apoptosis and necrosis. In addition, Ad-hIL-10 pretreatment diminished the release of cytochrome c from mitochondria into cytoplasm and caspase-3 activity, with simultaneous up-regulated of antioxidant HO-1 and anti-antiapoptotic Bcl-2 molecules.

CONCLUSION

Adenoviral gene transfer of hIL-10 ameliorated cold I/R injury by decreasing hepatic necrosis and apoptosis. The underlying mechanism of cytoprotective effects may at least be involved with the inhibition of caspase-3 activity and mitochondrial cytochrome c release, and the up-regulation of antiapoptotic (Bcl-2) and antioxidant (HO-1) molecules.

Apoptosis: A target for potentiation of UV-induced IL-1Ra synthesis by IVIg

IL-1Ra prevents IL-1 induced inflammatory signalling, a mechanism potentially important for several pathological conditions characterized by inflammation. When administered as a drug in the recombinant form, it displays a protective effect towards them. We postulated that this action could also be achieved by pharmacological activation of endogenous IL-1Ra production. We previously showed that photochemotherapy and UV-light increased monocyte/macrophages IL-1Ra secretion. A similar effect has been shown for IVIg. The aim of this study was to define optimal in vitro conditions for induction of IL-1Ra secretion. As both agents induce lymphocytes apoptosis, we focused our analysis on the influence of IVIg on UV-induced-IL-1Ra production on this mechanism. After overnight preincubation at 37 degrees C, UV-irradiated PBL mixed with two IVIg concentrations (1 and 25 mg/ml) were cocultured with autologous PBMC. Apoptosis was measured by annexin V/PI. IL-1Ra secretion was evaluated by RT-PCR and Luminex microbead array assay. A significant additive dose-dependent influence of IVIg (+85%; p=0.0005) on UV-induced IL-1Ra secretion, involved both Fc-receptor activation at a low dose (1 mg/ml) and a potent apoptotic action on PBL reinforcing the UV effect at high concentrations (25 mg/ml). We conclude that lymphocyte apoptosis represents an important pathway contributing to enhancement of UV-induced monocyte/macrophages IL-1Ra production by IVIg and that these findings should be considered when evaluating in vivo protocols for photochemotherapy and IVIg treatment, in hope of improving efficacy.

Prolonged skin allograft survival by IL-10 gene-introduced CD4 T cell administration

Both CD4 and CD8 T cells play crucial roles in immune responses in transplantation. Immunosuppressive drugs, such as FK506 and cyclosporin A, block the priming of alloreactive CD4 T(h) cells and the subsequent induction of allospecific CD8 cytotoxic effector T cells and inhibit allograft rejection. However, the desire to minimize chronic complications that may arise from the use of immunosuppressive agents drives the search for additional strategies for immunosuppression of allograft rejection. In this study, CD4 or CD8 T cells into which the IL-10 gene is introduced using an adenovirus vector containing human IL-10 (hIL-10) cDNA (Ad-hIL-10) and into mouse T cells transgenic for the Coxsackie virus and adenovirus receptor form a model system to study the effect of administration of IL-10-secreting T cells on the survival of the allogenic skin grafts. Ad-hIL-10-infected CD4 and CD8 T cells secreted a large amount of hIL-10 for 3-4 days in culture in vitro. Ad-hIL-10-infected CD4 T cells administered in vivo could be detected in the spleen for 7 days post-transfer. Significantly prolonged survival of grafts was observed in animals that received either Ad-hIL-10-infected activated CD4 T cells or T(h)2-skewed CD4 T cells as compared with controls. Furthermore, substantial enhancement of the effect was observed in B6.C-H2(bm1)/ByJ transplants. Thus, a direct manipulation of T cells through the introduction of the immunosuppressive cytokine gene IL-10 may be a novel strategy for the control of allograft rejection.

Interleukin-10 in viral diseases and cancer: exiting the labyrinth?

Interleukin-10 (IL-10) is unique among cytokines, as it is considered both as a potent immunostimulatory and immunosuppressive factor. This complex biology has been particularly challenging when trying to define the useful or harmful role of IL-10 in chronic viral diseases and cancer. In the present review, we emphasize how these multiple roles define IL-10 as an adaptive molecule, constantly tuning the host response against dangerous and resourceful pathogens.

Systemic administration of naked DNA with targeting specificity to mammalian kidneys

A major challenge for gene therapy is to be able to deliver efficiently the gene of interest to specific cell types. Here we describe a safe and simple effective naked DNA gene delivery method, via inferior vena cava (IVC) injection, to the recipient's kidneys. It was further demonstrated that gene expression was concentrated in the proximal tubular epithelial cells of the cortico-medullary region of the kidney. Confocal microscopy analyses demonstrated the presence of the exogenous DNA in the renal cell membrane 10 min postgene delivery. However, it was only by 30 min that the presence of the exogenous DNA could be detected in the cell cytoplasm and in the nuclei of the renal cells. Stable expression of the beta-galactosidase gene could be detected for up to 35 days and no toxicity or any adverse pathological effect associated with the delivery method could be observed. Importantly, this IVC gene delivery method could promote the targeting of genes to carcinoma established in the kidney of SCID mice. These results provide the first evidence to support that stable gene expression could be achieved in the renal cells of kidney and the established carcinoma in the kidneys following in vivo gene delivery with naked DNA and could therefore provide the potential to design protocols for the gene therapy of the kidney diseases.

Interleukin-10 therapy--review of a new approach

Interleukin (IL)-10 is an important immunoregulatory cytokine produced by many cell populations. Its main biological function seems to be the limitation and termination of inflammatory responses and the regulation of differentiation and proliferation of several immune cells such as T cells, B cells, natural killer cells, antigen-presenting cells, mast cells, and granulocytes. However, very recent data suggest IL-10 also mediates immunostimulatory properties that help to eliminate infectious and noninfectious particles with limited inflammation. Numerous investigations, including expression analyses in patients, in vitro and animal experiments suggest a major impact of IL-10 in inflammatory, malignant, and autoimmune diseases. So IL-10 overexpression was found in certain tumors as melanoma and several lymphomas and is considered to promote further tumor development. Systemic IL-10 release is a powerful tool of the central nervous system to prevent hyperinflammatory processes by activation of the neuro-endocrine axis following acute stress reactions. In contrast, a relative IL-10 deficiency has been observed and is regarded to be of pathophysiological relevance in certain inflammatory disorders characterized by a type 1 cytokine pattern such as psoriasis. Recombinant human IL-10 has been produced and is currently being tested in clinical trials. This includes rheumatoid arthritis, inflammatory bowel disease, psoriasis, organ transplantation, and chronic hepatitis C. The results are heterogeneous. They give new insight into the immunobiology of IL-10 and suggest that the IL-10/IL-10 receptor system may become a new therapeutic target.

Immunomodulation by interleukin-10 therapy decreases the incidence of relapse and prolongs the relapse-free interval in Psoriasis

The ability of interleukin-10 therapy to reduce the severity of exacerbated psoriasis has been demonstrated recently. Considering the immunobiologic properties of this cytokine we investigated the effects of long-term interleukin-10 application on the immune system and duration of psoriasis remission. We performed a placebo-controlled, double-blind, phase II trial using interleukin-10 in patients with chronic plaque psoriasis in remission. Patients received subcutaneous injections with either interleukin-10 (10 microg per kg body weight; n = 7) or placebo (n = 10) three times per week until relapse or study termination after 4 months. The treatment was well tolerated. In the placebo group almost all patients (90%) showed a relapse during the observation period. In contrast to this, only two of seven patients (28.6%) relapsed in the interleukin-10-treated group. Kaplan-Meier analysis revealed a significantly lower relapse incidence in the interleukin-10 than in the placebo group (p = 0.02). The mean relapse-free interval time was 101.6 +/- 12.6 d in the interleukin-10 group in comparison with 66.4 +/- 10.4 d in the placebo group. Immunologic activity of interleukin-10 application was indicated by an increase in soluble interleukin-2 receptor plasma levels and higher ex vivo interleukin-4 secretion capacities. Remarkably, a significant negative correlation was demonstrated between the interleukin-4 secretion capacity and Psoriasis Area and Severity Index score (r = -0.36, p < 0.01). Our data suggest that interleukin-10 therapy is immunologic effective, decreases the incidence of relapse and prolongs the disease-free interval in psoriasis. Its value should be further determined in larger trials and for the prevention of re-exacerbation of other inflammatory disorders with a similar immunologic profile.

The nasal epithelium as a factory for systemic protein delivery

We have previously shown that recombinant Sendai virus (SeV) produces efficient in vivo airway epithelial gene transfer. The ability to produce therapeutic levels of circulating proteins following noninvasive gene transfer would have widespread clinical application. Here, we compared nose, lung, and skeletal muscle for the ability to produce circulating levels of the secreted mouse antiinflammatory cytokine interleukin-10 (IL10) following SeV-mediated gene transfer. High levels of serum IL10 were obtained from each site with a potency order of lung > nose > muscle for a given viral titer. Serum levels from each site were within the likely required range for anti-inflammatory effects. The combination of a high-efficiency gene transfer agent (SeV) and sites that can be assessed noninvasively (nose or lung) may circumvent several current challenges to gene therapy.

Interleukin-10 and the interleukin-10 receptor

Interleukin-10 (IL-10), first recognized for its ability to inhibit activation and effector function of T cells, monocytes, and macrophages, is a multifunctional cytokine with diverse effects on most hemopoietic cell types. The principal routine function of IL-10 appears to be to limit and ultimately terminate inflammatory responses. In addition to these activities, IL-10 regulates growth and/or differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and endothelial cells. IL-10 plays a key role in differentiation and function of a newly appreciated type of T cell, the T regulatory cell, which may figure prominently in control of immune responses and tolerance in vivo. Uniquely among hemopoietic cytokines, IL-10 has closely related homologs in several virus genomes, which testify to its crucial role in regulating immune and inflammatory responses. This review highlights findings that have advanced our understanding of IL-10 and its receptor, as well as its in vivo function in health and disease.

Effects of Systemic Interleukin-10 Therapy on Psoriatic Skin Lesions: Histologic, Immunohistologic, and Molecular Biology Findings

Interleukin-10 is an important anti-inflammatory and immunosuppressive cytokine with major impact on several immune reactions, including regulatory mechanisms in the skin. Recently, we performed a phase II trial in psoriatic patients receiving subcutaneously interleukin-10 over 7 wk. The clinical response suggested that interleukin-10 might represent a novel anti-psoriatic drug. In order to understand better the mode of action and to elucidate the effects of systemic interleukin-10 treatment on the skin immune system, skin punch biopsies from sites different from interleukin-10 injection were analyzed. Biopsies were obtained from the patients before, at the end, and 3 wk after interleukin-10 therapy. The results are reported here. Histologic examination showed a decrease of several parameters reflecting the psoriatic disease activity as acanthosis and extension of the horny layer. Immunohistologic examination demonstrated decreasing numbers of infiltrating T cells, dermal CD1a+ cells, and a diminished proliferation of epidermal cells. Using a novel, quantitative reverse transcriptase-polymerase chain reaction approach a significant shift within the cytokine pattern was found. Interleukin-10 therapy led to a decrease of cutaneous interleukin-8 and interleukin-10 mRNA expression. Whereas no significant changes of interleukin-6, tumor necrosis factor-alpha, and interferon-gamma expression were found, interleukin-4 was strongly upregulated suggesting a shift from a type 1 towards a type 2 cytokine pattern. The changes within the local cytokine pattern seem to be disease-related, as an inverse course was found in a single interleukin-10 nonresponding patient. Our findings demonstrate considerable effects of systemic interleukin-10 application on the skin immune systems, which might contribute to the anti-psoriatic activity of interleukin-10.

Interleukin-10 and the Interleukin-10 Receptor

Interleukin-10 (IL-10), first recognized for its ability to inhibit activation and effector function of T cells, monocytes, and macrophages, is a multifunctional cytokine with diverse effects on most hemopoietic cell types. The principal routine function of IL-10 appears to be to limit and ultimately terminate inflammatory responses. In addition to these activities, IL-10 regulates growth and/or differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and endothelial cells. IL-10 plays a key role in differentiation and function of a newly appreciated type of T cell, the T regulatory cell, which may figure prominently in control of immune responses and tolerance in vivo. Uniquely among hemopoietic cytokines, IL-10 has closely related homologs in several virus genomes, which testify to its crucial role in regulating immune and inflammatory responses. This review highlights findings that have advanced our understanding of IL-10 and its receptor, as well as its in vivo function in health and disease.

Response of psoriasis to interleukin-10 is associated with suppression of cutaneous type 1 inflammation, downregulation of the epidermal interleukin-8/CXCR2 pathway and normalization of keratinocyte maturation

Psoriasis is a chronic inflammatory skin disease in which epidermal hyperplasia results from the release of cytokines by infiltrating type 1 T cells. Up- regulation of endogenous interleukin-10 controls type 1 skin responses in animal models; however, interleukin-10 production is low in psoriatic lesions. Consistent with an important role of interleukin-10 in psoriasis, we and colleagues have recently demonstrated clinical efficacy of subcutaneous administration of recombinant interleukin-10 to affected patients. Here, we studied the effects of interleukin-10 on disease-related inflammatory pathways. Patients were treated with recombinant interleukin-10 over 6 wk in an open-label phase II clinical trial. Tissue was obtained before and after therapy and examined by histology/immunohistochemistry, in situ hybridization, and quantitative real-time reverse transcription-polymerase chain reaction. Ten of 14 patients showed a marked reduction of the clinical disease activity. The clinical response was associated with a significant decrease of cutaneous T cell infiltration and the lesional expression of type 1 cytokines interferon-gamma and tumor necrosis factor-alpha. Interleukin-10 inhibited the epidermal interleukin-8 pathway by downregulating the expression of interleukin-8, its receptor CXCR2, and its inducer interleukin-17, and partially reversed the aberrant keratinocyte maturation defining psoriatic epidermal pathology. Remarkably, there was evidence that genetic factors are involved in the response to interleukin-10 as individual variations in the downregulation of tumor necrosis factor-alpha were related to the presence of polymorphisms in the tumor necrosis factor-alpha promoter. These data suggest that excessive production of type 1 cytokines in human skin disease can be counter-regulated by the administration of recombinant interleukin-10. Genotypic analysis may help to identify patients that will preferentially respond to interleukin-10 therapy.

Type 1/Type 2 immunity in infectious diseases

T helper type 1 (Th1) lymphocytes secrete secrete interleukin (IL)-2, interferon-gamma, and lymphotoxin-alpha and stimulate type 1 immunity, which is characterized by intense phagocytic activity. Conversely, Th2 cells secrete IL-4, IL-5, IL-9, IL-10, and IL-13 and stimulate type 2 immunity, which is characterized by high antibody titers. Type 1 and type 2 immunity are not strictly synonymous with cell-mediated and humoral immunity, because Th1 cells also stimulate moderate levels of antibody production, whereas Th2 cells actively suppress phagocytosis. For most infections, save those caused by large eukaryotic pathogens, type 1 immunity is protective, whereas type 2 responses assist with the resolution of cell-mediated inflammation. Severe systemic stress, immunosuppression, or overwhelming microbial inoculation causes the immune system to mount a type 2 response to an infection normally controlled by type 1 immunity. In such cases, administration of antimicrobial chemotherapy and exogenous cytokines restores systemic balance, which allows successful immune responses to clear the infection.

Prolongation of liver allograft survival after interleukin-10 gene transduction 24-48 hours before donation

BACKGROUND

Interleukin- (IL) 10 may be a potent regulator for controlling of allograft rejection. A single administration of IL-10 is not effective for controlling graft rejection. Gene transfer is an attractive vehicle for prolonging the expression of short-lived proteins.

METHODS

Donor or recipient livers were transduced with 1 x 10(10) p.f.u. of replication-deficient adenovirus vectors harboring human IL-10 cDNA (AdCMVhIL-10) via the ileocecal vein before or after rat orthotopic liver transplantation.

RESULTS

DA allografts given AdCMVhIL-10 24-48 hr before donation survived for more than 56 days in Lewis recipients, although DA allografts given the adenovirus vector 7 days or 6 hr before, and 3 days after transplantation were rejected within 30 days in recipients. Serum levels of human IL-10 in gene-transferred rats were maximum from day 2 to 7. The serum level of human IL-10 then decreased gradually, and human IL-10 was not detected by ELISA 30 days after gene-transduction. In gene-transduced long-term surviving liver allografts, IL-10 was expressed, and the expression of IL-4 was also up-regulated on posttransplant day 3, despite the expression of Th1 cytokines (IL-2 and interferon-gamma), although in rejected liver allografts, IL-2 and interferon-gamma were expressed without expression of IL-4 and IL-10.

CONCLUSIONS

The prolongation of survival of IL-10 cDNA transferred liver allografts might be due to inhibition of the early phase of alloimmune-response by over expression of IL-10, despite the expression of IL-2 and interferon-gamma.

Cold liver ischemia-reperfusion injury critically depends on liver T cells and is improved by donor pretreatment with interleukin 10 in mice

Kupffer cells are thought to mediate most of the deleterious effects of liver ischemia-reperfusion injury. The role of liver T cells and the impact of resident cell deactivation by interleukin 10 (IL-10) have never been addressed. Using a model of ex vivo liver cold ischemia and reperfusion, we assessed liver injury, tumor necrosis factor (TNF) and interferon gamma (IFN-gamma) release from livers of balb/c mice, nude mice, nude mice reconstituted with T cells, and gadolinium balb/c pretreated mice. The anti-inflammatory cytokine IL-10 was then used to define the best strategy of administration potentially able to modulate ischemia-reperfusion injury. For this purpose IL-10 was administered to the donor before liver harvesting, in the preservation medium during cold ischemia or during reperfusion. TNF and IFN-gamma were released time dependently and paralleled liver injury after reperfusion of cold preserved livers. Reperfused livers from nude or gadolinium pretreated mice disclosed a dramatic decrease in TNF and IFN-gamma release. Tissue injury was reduced by 51% in the absence of T cells and by 88% when Kupffer cells were deactivated. This effect was reverted by T-cell transfer to nude mice. Only donor pretreatment with IL-10 or IL-10 infusion during reperfusion led to a significant decrease in liver injury, TNF, and IFN-gamma release (-66% or -41%, -95% or -94%, and -70% or -70%, respectively). In conclusion, liver resident T cells are critically involved in cold ischemia-reperfusion injury and pretreatment of the donor with IL-10 decreases liver injury and the release of T-cell- and macrophage-dependent cytokines.

A single amino acid determines the immunostimulatory activity of interleukin 10

Cellular interleukin 10s (cIL-10s) of human and murine origin have extensive sequence and structural homology to the Epstein-Barr virus BCRF-I gene product, known as viral IL-10 (vIL-10). Although these cytokines share many immunosuppressive properties, vIL-10 lacks several of the immunostimulatory activities of cIL-10 on certain cell types. The molecular and cellular bases for this dichotomy are not currently defined. Here, we show that the single amino acid isoleucine at position 87 of cIL-10 is required for its immunostimulatory function. Substitution of isoleucine in cIL-10 with alanine, which corresponds to the vIL-10 residue, abrogates immunostimulatory activity for thymocytes, mast cells, and alloantigenic responses while preserving immunosuppressive activity for inhibition of interferon gamma production and prolongation of cardiac allograft survival. Conversely, substitution of alanine with isoleucine in vIL-10 converts it to a cIL-10-like molecule with immunostimulatory activity. This single conservative residue alteration significantly affects ligand affinity for receptor; however, affinity changes do not necessarily alter specific activities for biologic responses in a predictable fashion. These results suggest complex regulation of IL-10 receptor-ligand interactions and subsequent biological responses. These results demonstrate that vIL-10 may represent a captured and selectively mutated cIL-10 gene that benefits viral pathogenesis by leading to ineffective host immune responses. The ability to manipulate the activity of IL-10 in either a stimulatory or suppressive direction may be of practical value for regulating immune responses for disease therapy, and of theoretical value for determining what aspects of IL-10 activity are important for normal T cell responses.

The treatment of psoriasis with IL-10: rationale and review of the first clinical trials

By virtue of its anti-inflammatory and immunosuppressive properties, IL-10 plays a crucial role in several immune reactions, including regulatory mechanisms in the skin. In psoriasis, a common cutaneous immune disease, a relative deficiency in cutaneous IL-10 expression is observed. Several lines of evidence suggest that IL-10 could have antipsoriatic abilities. One pilot and two Phase II trials with sc. IL-10 administration over 3 - 7 weeks in patients with moderate to severe psoriasis have supported this hypothesis. The therapy was well-tolerated and clinical efficiency was found in the majority of patients. Immunosuppressive effects (depressed monocytic HLA-DR expression, TNF-alpha and IL-12 secretion capacity, IL-12 plasma levels and responsiveness to recall antigens) as well as a shift towards a Type 2 cytokine pattern (increasing proportion of IL-4, IL-5, and IL-10 producing T-cells, selective increase in IgE serum levels) were observed. These investigations suggest that IL-10 is of major importance in psoriasis and show that IL-10 administration represents a new therapeutic approach. However, long-term administration of large recombinant protein limits the value of this novel therapeutic approach. As such, neither oral nor topical applications are possible; there is a risk of the development of neutralising antibodies.

Differential effects of exogenous interleukin-10 on cardiac allograft survival: inhibition of rejection by recipient pretreatment reflects impaired host accessory cell function

BACKGROUND

There have been conflicting reports of the influence of exogenous mammalian interleukin (IL)-10 on immune reactivity. These findings may reflect the pleiotropic effects of IL-10 on the functions of antigen-presenting cells and immune effector cells. The purpose of this study was to extend observations of the influence of the cytokine on organ allograft survival and to investigate its effects on the function of accessory and immune effector cells in a mouse cardiac transplant model.

METHODS

C3H (H2k) recipients of heterotopic vascularized B10 (H-2b) heart allografts were treated with recombinant (r) mouse IL-10 over a wide range of doses (0.2-200 microg/day), either before the transplant (days -3, -2, -1), peri-operatively (days -1, 0, 1), or after the transplant (days 0-6). Anti-donor cytotoxic T lymphocyte activity of host spleen and graft-infiltrating cells, and circulating complement-dependent cytotoxic antibody titers were determined by isotope release assays. Mixed leukocyte reactions were used to determine the influence of IL-10 on the function of antigen-presenting cells and allogeneic responder T cells.

RESULTS

Recipient pre-transplant administration of IL-10 (days -3, -2, -1) prolonged graft survival at all doses tested. Donor pretreatment with IL-10 (25 microg/day; days -3, -2, -1) was also effective, but less. A pre-transplant or perioperative course of IL-10, however, did not significantly affect the immunosuppressive action of tacrolimus given on days 0-6. If given only after the transplant, IL-10 either had no effect on graft survival or (at high dosage) accelerated rejection and prevented the immunosuppressive effect of cyclosporine. Pretransplant treatment of graft recipients with IL-10 reduced splenic anti-donor cytotoxic T lymphocyte activity and the incidence of graft-infiltrating CD8+ cells. There was no significant effect on circulating alloantibody titers. MLR assays revealed that preincubation of responder cells, but not stimulator spleen cells with IL-10, inhibited T cell proliferation, whereas addition of IL-10 after the start of culture modestly enhanced proliferation. Preincubation of purified T responders with IL-10 showed no inhibitory effect.

CONCLUSION

The modest and opposing effects of exogenous IL-10 on organ allograft survival are dependent on timing and dosage. Recipient pretreatment prolongs graft survival. This finding, together with the MLR results, suggest that IL-10 inhibits the function of host immune accessory cells and that the direct pathway of alloantigen presentation may be less susceptible to inhibition by IL-10.

CD3 antibody-induced IL-10 in renal allograft recipients: an in vivo and in vitro analysis

BACKGROUND

The first administration of CD3 monoclonal antibodies, such as anti-human CD3 (OKT3), induces a massive release of several cytokines, including tumor necrosis factor alpha (TNF-alpha), interferon (IFN)-gamma, interleukin (IL)-2, IL-3, IL-6, and granulocyte-macrophage colony-stimulating factor.

METHODS

Cytokine levels in patient's sera were measured by specific ELISA. In vitro cultures were performed using OKT3-stimulated peripheral blood mononuclear cells and/or whole blood from patients and normal controls.

RESULTS

Here we describe that OKT3 administration to human renal allograft recipients also leads to a significant release of IL-10. Contrasting with most OKT3-induced cytokines, such as TNF-alpha whose release is transient, IL-10 levels show a more progressive increase, they peak only by 4-8 hr after the first OKT3 injection and persist longer. Thus, significant IL-10 levels are still detectable at the time of the second and the third OKT3 injection. Administration of corticosteroids, 1 hr before the first OKT3 injection, significantly reduced both TNF-alpha and IL-10 release. Experiments were performed to evaluate the source(s) of IL-10 and its (their) influence on the initial T-cell activation. When stimulated in culture with soluble OKT3, the production of IL-10 was dependent on the cooperation between T lymphocytes and monocytes. It is important that, as assessed through the use of a specific neutralizing antibody, the endogenous IL-10 produced in the co-culture system exerted a negative feed-back on the release of the other pro-inflammatory CD3-induced cytokines, which was reproducible.

CONCLUSION

These results are supportive of a major role of IL-10 in the down-modulation of the OKT3-triggered T-cell activation cascade.

Down-regulation of interleukin-2 and interferon-gamma and maintenance of interleukin-4 and interleukin-10 production after administration of an anti-CD3 monoclonal antibody in mice

BACKGROUND

Activating anti-CD3 monoclonal antibodies (mAbs), such as OKT3, are potent immunosuppressive agents that are widely used in clinical transplantation. We investigated whether the in vivo induction of T cell unresponsiveness contributes to the immunosuppressive properties of the anti-mouse-CD3 mAb 145-2C11.

METHODS

After a single in vivo administration of 145-2C11 residual T cells were restimulated in vivo and in vitro to assess cytokine production. Mice were also transplanted with allogeneic skin 9 days after 145-2C11 administration to investigate whether the immunosuppressive properties of the antibody persist after the reexpression of the T cell receptor.

RESULTS

Pretreatment with anti-CD3 mAbs caused a profound deficit in both interleukin- (IL) 2 and interferon- (IFN) y secretion upon restimulation in vivo, whereas IL-4 was only partially inhibited and IL-10 production was significantly increased. Purified T cells obtained from mice injected with anti-CD3 mAb also displayed deficient IL-2 and IFN-gamma production together with persisting IL-4 and IL-10 secretion. 145-2C11 had immunosuppressive properties that per sisted after the reexpression of the T cell receptor because mice transplanted with allogeneic skin 9 days after a single anti-CD3 mAb injection still had significantly prolonged graft survival (14.1+/-0.6 days vs. 10.7+/-0.4 days in controls, P<0.02). Blocking IL-4 and IL-10 by neutralizing mAbs further prolonged skin graft survival in mice injected with 145-2C11 (18.3+/-0.7 vs. 14.8+/-0.6 days, P<0.02).

CONCLUSION

The in vivo administration of the 145-2C11 anti-CD3 mAb results in the selective inhibition of Thl-type cytokine secretion upon restimulation, which correlates with a state of immunosuppression. The persistent production of Th2-type cytokines does not contribute to the anti-CD3 mAb-mediated prolonged survival of skin allografts in our experimental model.

Interleukin-10-induced CD8 cell proliferation

Interleukin (IL)-10, a product of T helper 2 (Th2) lymphocytes, has been shown to be an important regulator of lymphoid and myeloid cells, inhibiting mitogen, peptide and alloantigen-induced T-cell proliferation and IL-2 production. The microenvironment at the time of cell activation, notably the presence or absence of cytokines such as IL-10, interferon-gamma (IFN-gamma) and IL-2, is believed to determine the lineage and magnitude of cell-mediated responses. In this study, we show that recombinant human IL-10 (rhIL-10) exerts a dose-dependent inhibitory effect on human peripheral blood mononuclear cells stimulated in vitro, when these cells have not previously been exposed to rhIL-10. Furthermore, incubation of these cells with high doses of rhIL-10, either before or at the time of activation, results in inhibition which is followed several days later by the emergence of a population of CD8 positive cells. This rhIL-10-responsive CD8, positive cell population still emerges even when the cells are washed following incubation with rhIL-10 prior to cell activation. Using purified CD8 populations this was shown to be a direct action of rhIL-10 on CD8 cells and not via CD4 positive cells and monocytes. This finding was only observed when cells were activated with a cross-linking anti-CD3 antibody and not when activated with phorbol-12-mystrate-13-acetate (PMA) and calcium ionophore (CaIon), suggesting that the effect is mediated through cell-surface receptors. Analysis of CD8 positive clones reveal production of Tc2 patterns of cytokines and reduced cell cytotoxicity to allogeneic, natural killer and lymphokine activated cell targets.

Recent advances in immunosuppressants

In recent years, a large number of structurally diverse immunosuppressants have been discovered that are effective for the treatment of organ transplantation. Some of them are undergoing clinical trials and may soon enter into routine clinical practice. These compounds are either chemical entities obtained from natural sources/synthetic means or biomaterials such as monoclonal antibodies/gene products/proteins. They have been found to interfere at different stages of T cell activation and proliferation, and can be identified as inhibitors of nucleotide synthesis, growth factor signal transduction and differentiation. Newer strategies involving combination of new agents with traditional immunosuppressants, monoclonal antibodies and gene therapy offer enormous potential, not only for the investigation of mechanisms pertaining to graft rejection, but also for its therapeutic prevention.

Allograft transduction of IL-10 prolongs survival following orthotopic liver transplantation

Interleukin-10 (IL-10) is an ideal candidate cytokine for suppressing the alloimmune response in transplantation. To determine whether genetic modulation of the hepatic graft with IL-10 could prolong survival following orthotopic liver transplantation, we constructed a replication-deficient adenovirus vector expressing human IL-10 (AdCMVhIL-10). Intraportal injection of this vector into a donor rat 24-48 h before grafting resulted in efficient release of IL-10 into the circulation of a recipient rat after transplantation. Moreover, levels of hIL-10 from the suprahepatic vena cava were significantly (1.48-fold) higher than those from the infrahepatic vena cava (P = 0.013), indicating local IL-10 production within the transduced hepatic graft. AdCMVhIL-10 induced a prolongation of median survival to more than 87 days, with two of five transduced grafts showing more than 100 days of ongoing survival, when compared with 11 days for grafts transduced with a control adenovirus vector carrying the E. coli beta-galactosidase gene (P = 0.0021) and 11 days for untreated grafts (P = 0.0021). Pathological findings occurring in the AdCMVhIL-10-transduced hepatic grafts revealed no evidence of progressive rejection reaction resulting in graft failure. These results demonstrate that hepatic grafts modulated by IL-10 gene transfer make local and effective immunosuppression feasible in the transplantation setting.

In vivo generation of C4d, Bb, iC3b, and SC5b-9 after OKT3 administration in kidney and lung transplant recipients

BACKGROUND

OKT3 monoclonal antibody therapy results in an acute clinical syndrome (ACS) associated with the release of tumor necrosis factor and sequestration of neutrophils in the lungs. We have previously shown that inhibition of tumor necrosis factor does not completely eliminate OKT3-ACS, suggesting that other factors also contribute to the ACS. The current studies analyzed complement activation in vivo during the first hour after OKT3 administration.

METHODS

Renal (n=4) and lung (n=4) transplant recipients received OKT3 as treatment for rejection and induction therapy, respectively. Complement activation products C4d, Bb, iC3b, and SC5b-9 were measured by ELISA. Hemodynamic parameters were also monitored in the lung transplant recipients. Neutrophil expression of CD11a, CD11b, and CD18 was monitored by flow cytometry. Controls included patients receiving methylprednisolone for rejection (n=4), two adults with adult respiratory distress syndrome who received extracorporeal membrane oxygenation, and normal volunteers (n=5). P values less than 0.05 (*) were considered significant.

RESULTS

Increases in the plasma levels of C4d, Bb, iC3b, and SC5b-9 were observed in seven of eight patients after OKT3 administration. Mean values (n=8) at 0, 15, and 60 min (in microg/ml) were as follows-C4d: 1.865, 2.644*, and 2.607*; Bb: 0.245, 0.411, and 0.385; iC3b: 10.881, 17.242*, and 15.145*; and SC5b-9: 0.232, 0.269, and 0.302*. An increase in CD11b and CD18 and a decrease of CD11a on neutrophils in parallel with complement activation was observed. In lung transplant recipients, C3 activation correlated with increases in mean pulmonary and central venous pressures (P<0.05). As compared with extracorporeal membrane oxygenation, which activated classical and alternative pathways, OKT3 predominantly activated complement by the classical pathway. Methylprednisolone pulses did not activate complement.

CONCLUSIONS

Complement activation is an early event after OKT3 administration and is associated with the increased expression of adhesion molecules on neutrophils and with pulmonary hemodynamic changes. Effective therapeutic approaches to the control of early monoclonal antibody side effects may require measures that limit complement activation in addition to reducing cytokine activity.

Adenovirus-mediated interleukin-10 gene transfer inhibits post-transplant fibrous airway obliteration in an animal model of bronchiolitis obliterans

Bronchiolitis obliterans, a form of chronic allograft rejection characterized by progressive fibrous obliteration of the airways, is the major obstacle limiting prolonged survival of lung transplant recipients. To date, no effective therapy against this fatal complication exists. Interleukin-10 (IL-10), an anti-inflammatory and immunosuppressive cytokine, inhibits various T cell and antigen-presenting cell functions. We examined the effect of IL-10 in an animal model for bronchiolitis obliterans. A heterotopic tracheal transplant model was used. IL-10 was administered to the recipient either in its recombinant form by osmotic minipump or by adenoviral-mediated IL-10 gene transfer (Ad5E1mIL-10). Successful gene transfection and expression was confirmed by measuring circulating IL-10 protein. Tracheal allografts were assessed histologically based on a scoring system. IL-10 administration (in recombinant form or by gene transfer) inhibited the development of fibrous airway obliteration 3 weeks after transplantation in comparison to untreated controls (p < 0.05). This was demonstrated only if the delivery was initiated 5 days after transplantation and not if it was started at the time of transplantation. A single administration of the gene construct was sufficient to achieve the desired effect. We have shown that IL-10 can prevent the development of airway fibro-obliteration in this model. Gene transfection at a site distant from a graft can be used to produce a desired effect on the graft. IL-10 may be of major importance in the control of post-transplant bronchiolitis obliterans. The timing of its administration is critical and further studies are required to determine the mechanisms underlying the observed effects of IL-10.