The secreted form of the p40 subunit of interleukin (IL)-12 inhibits IL-23 functions and abrogates IL-23-mediated antitumour effects

Interleukin-23 Involved in Fibrotic Autoimmune Diseases: New Discoveries

Interleukin (IL)-23 is a central pro-inflammatory cytokine with a broad range of effects on immune responses. IL-23 is pathologically linked to the induction of the production of the pro-inflammatory cytokines IL-17 and IL-22, which stimulate the differentiation and proliferation of T helper type 17 (Th17) cells. Recent discoveries suggest a potential pro-fibrotic role for IL-23 in the development of chronic inflammatory autoimmune diseases characterized by intense fibrosis. In this review, we summarized the biological features of IL-23 and gathered recent research on the role of IL-23 in fibrotic autoimmune conditions, which could provide a theoretical basis for clinical targeting and drug development.

Interleukin 17 and Its Involvement in Renal Cell Carcinoma

Nowadays, molecular and immunological research is essential for the better understanding of tumor cells pathophysiology. The increasing number of neoplasms has been taken under ‘the molecular magnifying glass’ and, therefore, it is possible to discover complex relationships between the cytophysiology and immune system action. An example could be renal cell carcinoma (RCC) which has deep interactions with immune mediators such as Interleukin 17 (IL-17)—an inflammatory cytokine reacting to tissue damage and external pathogens. RCC is one of the most fatal urological cancers because of its often late diagnosis and poor susceptibility to therapies. IL-17 and its relationship with tumors is extremely complex and constitutes a recent topic for numerous studies. What is worth highlighting is IL-17’s dual character in cancer development—it could be pro- as well as anti-tumorigenic. The aim of this review is to summarize the newest data considering multiple connections between IL-17 and RCC.

A novel cytokine consisting of the p40 and EBI3 subunits suppresses experimental autoimmune arthritis via reciprocal regulation of Th17 and Treg cells

OBJECTIVE

The interleukin (IL)-12 cytokine family is closely related to the development of T helper cells, which are responsible for autoimmune disease enhancement or suppression. IL-12 family members are generally heterodimers and share three α-subunits (p35, p19, and p28) and two β-subunits (p40 and EBI3). However, a β-sheet p40 homodimer has been shown to exist and antagonize IL-12 and IL-23 signaling ¹. Therefore, we assumed the existence of a p40-EBI3 heterodimer in nature and sought to investigate its role in immune regulation.

METHODS

The presence of the p40-EBI3 heterodimer was confirmed by ELISA, immunoprecipitation, and western blotting. A p40-EBI3 vector and p40-EBI3-Fc protein were synthesized to confirm the immunological role of this protein in mice with collagen-induced arthritis (CIA). The anti-inflammatory effects of p40-EBI3 were analyzed with regard to clinical, histological, and immune cell-regulating features in mice with CIA.

RESULTS

Clinical arthritis scores and the expression levels of proinflammatory cytokines (e.g., IL-17, IL-1β, IL-6, and TNF-α) were significantly attenuated in p40-EBI3-overexpressing and p40-EBI3-Fc-treated mice with CIA compared to vehicle-treated mice with CIA. Structural joint damage and vessel formation-related gene expression were also reduced by p40-EBI3 heterodimer treatment. In vitro, the p40-EBI3-Fc protein significantly suppressed the differentiation of Th17 cells and reciprocally induced CD4⁺CD25⁺Foxp3⁺ (regulatory T) cells. p40-EBI3 also inhibited osteoclast formation in a concentration-dependent manner.

CONCLUSION

In this study, p40-EBI3 ameliorated proinflammatory conditions both in vivo and in vitro. We propose that p40-EBI3 is a novel anti-inflammatory cytokine involved in suppressing the immune response through the expansion of Treg cells and suppression of Th17 cells and osteoclastogenesis.

Tryptophan (W) at position 37 of murine IL-12/IL-23 p40 is mandatory for binding to IL-12Rβ1 and subsequent signal transduction

Interleukin (IL)-12 and IL-23 are composite cytokines consisting of p35/p40 and p19/p40, respectively, which signal via the common IL-12 receptor β1 (IL-12Rβ1) and the cytokine-specific receptors IL-12Rβ2 and IL-23R. Previous data showed that the p40 component interacts with IL-12Rβ1, whereas p19 and p35 subunits solely bind to IL-23R and IL-12Rβ2, resulting in tetrameric signaling complexes. In the absence of p19 and p35, p40 forms homodimers and may induce signaling via IL-12Rβ1 homodimers. The critical amino acids of p19 and p35 required for binding to IL-23R and IL-12Rβ2 are known, and two regions of p40 critical for binding to IL-12Rβ1 have recently been identified. In order to characterize the involvement of the N-terminal region of p40 in binding to IL-12Rβ1, we generated deletion variants of the p40-p19 fusion cytokine. We found that an N-terminal deletion variant missing amino acids M23 to P39 failed to induce IL-23-dependent signaling and did not bind to IL-12Rβ1, whereas binding to IL-23R was maintained. Amino acid replacements showed that p40W37K largely abolished IL-23-induced signal transduction and binding to IL-12Rβ1, but not binding to IL-23R. Combining p40W37K with D36K and T38K mutations eliminated the biological activity of IL-23. Finally, homodimeric p40D36K/W37K/T38K did not interact with IL-12Rβ1, indicating binding of homodimeric p40 to IL-12Rβ1 is comparable to the interaction of IL-23/IL-12 and IL-12Rβ1. In summary, we have defined D36, W37, and T38 as hotspot amino acids for the interaction of IL-12/IL-23 p40 with IL-12Rβ1. Structural insights into cytokine–cytokine receptor binding are important to develop novel therapeutic strategies.

Efficacy and safety of tildrakizumab in patients with active psoriatic arthritis: results of a randomised, double-blind, placebo-controlled, multiple-dose, 52-week phase IIb study

Objectives

To evaluate efficacy and safety of the anti-interleukin-23p19 monoclonal antibody tildrakizumab in patients with psoriatic arthritis (PsA).

Methods

In this randomised, double-blind, placebo-controlled, phase IIb study, patients with active PsA were randomised 1:1:1:1:1 to tildrakizumab 200 mg every 4 weeks (Q4W); tildrakizumab 200, 100 or 20 mg Q12W; or placebo Q4W. Patients receiving tildrakizumab 20 mg or placebo switched to tildrakizumab 200 mg Q12W at W24; treatment continued to W52. The primary efficacy endpoint was proportion of patients with ACR20 response (≥20% improvement by American College of Rheumatology criteria) at W24. Secondary efficacy endpoints were assessed without adjustment for multiplicity. Safety was evaluated from treatment-emergent adverse events (TEAEs).

Results

391/500 patients screened were randomised and treated. At W24, 71.4%–79.5% of tildrakizumab-treated versus 50.6% of placebo-treated patients achieved ACR20 (all p<0.01). Patients receiving tildrakizumab versus placebo generally achieved higher rates of ACR50, Disease Activity Score in 28 joints with C reactive protein <3.2, minimal disease activity and 75%/90%/100% improvement from baseline Psoriasis Area and Severity Index responses at W24 and through W52. Improvement in dactylitis and enthesitis was not observed; results were mixed for other outcomes. Responses in patients switched to tildrakizumab 200 mg at W24 were consistent with treatment from baseline. TEAEs and serious TEAEs occurred in 64.5% and 3.3%, respectively, of all patients through W52 and were comparable among treatment arms.

Conclusions

Tildrakizumab treatment significantly improved joint and skin manifestations of PsA other than dactylitis and enthesitis. Treatment was generally well tolerated through W52. Clinicaltrials.gov NCT02980692.

IL-12 and IL-23-Close Relatives with Structural Homologies but Distinct Immunological Functions

Cytokines of the IL-12 family show structural similarities but have distinct functions in the immune system. Prominent members of this cytokine family are the pro-inflammatory cytokines IL-12 and IL-23. These two cytokines share cytokine subunits and receptor chains but have different functions in autoimmune diseases, cancer and infections. Accordingly, structural knowledge about receptor complex formation is essential for the development of new therapeutic strategies preventing and/or inhibiting cytokine:receptor interaction. In addition, intracellular signaling cascades can be targeted to inhibit cytokine-mediated effects. Single nucleotide polymorphisms can lead to alteration in the amino acid sequence and thereby influencing protein functions or protein–protein interactions. To understand the biology of IL-12 and IL-23 and to establish efficient targeting strategies structural knowledge about cytokines and respective receptors is crucial. A highly efficient therapy might be a combination of different drugs targeting extracellular cytokine:receptor assembly and intracellular signaling pathways.

Role of interleukin-23/interleukin-17 axis in T-cell-mediated actions in hypertension

Current knowledge suggests that hypertension is in part mediated by immune mechanisms. Both interleukin (IL)-23 and IL-17 are up-regulated in several experimental hypertensive rodent models, as well as in hypertensive humans in observational studies. Recent preclinical studies have shown that either IL-23 or IL-17A treatment induce blood pressure elevation. However, the IL-23/IL-17 axis has not been a major therapeutic target in hypertension, unlike in other autoimmune diseases. In this review, we summarize current knowledge on the role of these cytokines in immune mechanisms contributing to hypertension, and discuss the potential of IL-23/IL-17-targeted therapy for treatment of hypertension.

Phage Display Derived Monoclonal Antibodies: From Bench to Bedside

Monoclonal antibodies (mAbs) have become one of the most important classes of biopharmaceutical products, and they continue to dominate the universe of biopharmaceutical markets in terms of approval and sales. They are the most profitable single product class, where they represent six of the top ten selling drugs. At the beginning of the 1990s, an in vitro antibody selection technology known as antibody phage display was developed by John McCafferty and Sir. Gregory Winter that enabled the discovery of human antibodies for diverse applications, particularly antibody-based drugs. They created combinatorial antibody libraries on filamentous phage to be utilized for generating antigen specific antibodies in a matter of weeks. Since then, more than 70 phage–derived antibodies entered clinical studies and 14 of them have been approved. These antibodies are indicated for cancer, and non-cancer medical conditions, such as inflammatory, optical, infectious, or immunological diseases. This review will illustrate the utility of phage display as a powerful platform for therapeutic antibodies discovery and describe in detail all the approved mAbs derived from phage display.

Deciphering site 3 interactions of interleukin 12 and interleukin 23 with their cognate murine and human receptors

Interleukin (IL)-12 and IL-23 belong to the IL-12 type family and are composite cytokines, consisting of the common β subunit p40 and the specific cytokine α subunit p35 and p19, respectively. IL-12 signals via the IL-12Rβ1·IL-12Rβ2 receptor complex, and IL-23 uses also IL-12Rβ1 but engages IL-23R as second receptor. Importantly, binding of IL-12 and IL-23 to IL-12Rβ1 is mediated by p40, and binding to IL-12Rβ2 and IL-23R is mediated by p35 and p19, respectively. Previously, we have identified a W157A substitution at site 3 of murine IL-23p19 that abrogates binding to murine IL-23R. Here, we demonstrate that the analogous Y185R site 3 substitution in murine and Y189R site 3 substitution in human IL-12p35 abolishes binding to IL-12Rβ2 in a cross-species manner. Although Trp¹⁵⁷ is conserved between murine and human IL-23p19 (Trp¹⁵⁶ in the human ortholog), the site 3 W156A substitution in hIL-23p19 did not affect signaling of cells expressing human IL-12Rβ1 and IL-23R, suggesting that the interface of murine IL-23p19 required for binding to IL-23R is different from that in the human ortholog. Hence, we introduced additional hIL-23p19 substitutions within its binding interface to hIL-23R and found that the combined site 3 substitutions of W156A and L160E, which become buried at the complex interface, disrupt binding of hIL-23p19 to hIL-23R. In summary, we have identified substitutions in IL-12p35 and IL-23p19 that disrupt binding to their cognate receptors IL-12Rβ2 and IL-23R in a murine/human cross-species manner.

Novel functions of grass carp three p40 isoforms as modulators of Th17 signature cytokine expression in head kidney leukocytes

Interleukin (IL)-12p40, a component of IL-12 and IL-23, can be secreted as monomer and homodimer in mammals. Our previous study has proved the existence of natural three p40 isoforms and their proinflammatory properties in grass carp. In the present study, we unexpectedly found that recombinant grass carp p40a/b/c (rgcp40a, rgcp40b and rgcp40c) were able to enhance the mRNA levels of grass carp il-17a/f1 (gcil-17a/f1) in a dose- and time-dependent manner in head kidney leukocytes (HKLs). In agreement with these findings, the enzyme-linked immunosorbent assay (ELISA) showed that rgcp40a, rgcp40b and rgcp40c markedly stimulated gcIl-17a/f1 secretion from the HKLs. Together with their stimulatory effects on grass carp gcil-22 and gcil-26 expression, our data suggested their potential to mediate Th17-like response in grass carp. To support this notion, we investigated the underlying mechanisms for the regulation of rgcp40 isoforms on gcil-17a/f1 expression, and found that three rgcp40 isoforms significantly induced the activation of Erk, Jnk and Stat3 pathways in a time-dependent oscillation in the same cell model. Moreover, three rgcp40 isoforms-induced gcil-17a/f1 mRNA expression was suppressed by the inhibition on Erk, Jnk and Stat3 pathways, suggesting the signaling pathways in the p40 isoforms-mediating il-17a/f1 transcription. These studies for the first time proved the involvement of three gcp40 isoforms in mediating Th17 signature cytokine expression in fish immune cells, therefore providing new insights into the roles of p40 in teleost immunity.

Phage Display Derived Monoclonal Antibodies: From Bench to Bedside

Monoclonal antibodies (mAbs) have become one of the most important classes of biopharmaceutical products, and they continue to dominate the universe of biopharmaceutical markets in terms of approval and sales. They are the most profitable single product class, where they represent six of the top ten selling drugs. At the beginning of the 1990s, an in vitro antibody selection technology known as antibody phage display was developed by John McCafferty and Sir. Gregory Winter that enabled the discovery of human antibodies for diverse applications, particularly antibody-based drugs. They created combinatorial antibody libraries on filamentous phage to be utilized for generating antigen specific antibodies in a matter of weeks. Since then, more than 70 phage-derived antibodies entered clinical studies and 14 of them have been approved. These antibodies are indicated for cancer, and non-cancer medical conditions, such as inflammatory, optical, infectious, or immunological diseases. This review will illustrate the utility of phage display as a powerful platform for therapeutic antibodies discovery and describe in detail all the approved mAbs derived from phage display.

Production and functional insights into the potential regulation of three isoforms of grass carp p40 subunit in inflammation

The p40 subunit is known as a component of Interleukin (IL)-12 and IL-23. In mammals, p40 can be secreted as a monomer or homodimer and acts independently to mediate cellular responses. Recently, three p40 paralogues were isolated and identified from grass carp and other fish species, but whether they exist independently as well as their functional consequences and significance remain unclear. In the present study, using grass carp as the model, we for the first time demonstrated the existence of natural fish p40a, p40b and p40c (gcp40a, gcp40b and gcp40c) mainly as a monomer in culture supernatant of head kidney leukocytes (HKLs). Particularly, their excessive secretion induced by various immune stimuli suggests possible involvement of free p40s in fish immune responses. To define their functions, recombinant grass carp p40a/b/c (rgcp40a, rgcp40b and rgcp40c) were prepared by Pichia pastoris expression system, and they possessed the activities to enhance the secretion of pro-inflammatory cytokines including Il-1β and tumor necrosis factor-α (Tnf-α) in grass carp HKLs. These pro-inflammatory properties of p40 isoforms prompted us to investigate their roles during the inflammatory process. In line with this, in vivo study revealed the pathogenic effect of rgcp40a on intestinal inflammation, whereas gcp40a polyclonal antibodies remarkably ameliorated Aeromonas hydrophila-induced intestinal histopathological changes. Taken together, our results uncover the biological significance of free p40s in teleost, and provide new clue for targeting fish intestinal inflammation.

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.

IL-23R Signaling Plays No Role in Myocardial Infarction

Ischemic heart diseases are the most frequent diseases in the western world. Apart from Interleukin (IL-)1, inflammatory therapeutic targets in the clinic are still missing. Interestingly, opposing roles of the pro-inflammatory cytokine IL-23 have been described in cardiac ischemia in mice. IL-23 is a composite cytokine consisting of p19 and p40 which binds to IL-23R and IL-12Rβ1 to initiate signal transduction characterized by activation of the Jak/STAT, PI3K and Ras/Raf/MAPK pathways. Here, we generate IL-23R-Y416FΔICD signaling deficient mice and challenged these mice in close- and open-chest left anterior descending coronary arteria ischemia/reperfusion experiments. Our experiments showed only minimal changes in all assayed parameters in IL-23R signaling deficient mice compared to wild-type mice in ischemia and for up to four weeks of reperfusion, including ejection fraction, endsystolic volume, enddiastolic volume, infarct size, gene regulation and α smooth muscle actin (αSMA) and Hyaluronic acid (HA) protein expression. Moreover, injection of IL-23 in wild-type mice after LAD ischemia/reperfusion had also no influence on the outcome of the healing phase. Our data showed that IL-23R deficiency has no effects in myocardial I/R.

Interleukin (IL)-12 and IL-23 and Their Conflicting Roles in Cancer

The balance of proinflammatory cytokines interleukin (IL)-12 and IL-23 plays a key role in shaping the development of antitumor or protumor immunity. In this review, we discuss the role IL-12 and IL-23 plays in tumor biology from preclinical and clinical data. In particular, we discuss the mechanism by which IL-23 promotes tumor growth and metastases and how the IL-12/IL-23 axis of inflammation can be targeted for cancer therapy.

RNAseq reveals hypervirulence-specific host responses to M. tuberculosis infection

The distinguishing factors that characterize the host response to infection with virulent Mycobacterium tuberculosis (M.tb) are largely confounding. We present an infection study with 2 genetically closely related M.tb strains that have vastly different pathogenic characteristics. The early host response to infection with these detergent-free cultured strains was analyzed through RNAseq in an attempt to provide information on the subtleties which may ultimately contribute to the virulent phenotype. Murine bone marrow derived macrophages (BMDMs) were infected with either a hyper- (R5527) or hypovirulent (R1507) Beijing M. tuberculosis clinical isolate. RNAseq revealed 69 differentially expressed host genes in BMDMs during comparison of these 2 transcriptomes. Pathway analysis revealed activation of the stress-induced and growth inhibitory Gadd45 signaling pathway in hypervirulent infected BMDMs. Upstream regulators of interferon activation such as and IRF3 and IRF7 were predicted to be upregulated in hypovirulent-infected BMDMs. Additional analysis of the host immune response through ELISA and qPCR included the use of human THP-1 macrophages where a robust proinflammatory response was observed after infection with the hypervirulent strain. RNAseq revealed 2 early-response genes (ier3 and saa3) and 2 host-defense genes (oasl1 and slpi) that were significantly upregulated by the hypervirulent strain. The role of these genes under M.tb infection conditions are largely unknown but here we provide validation of their presence with use of qPCR and Western blot. Further analysis into their biological role during infection with virulent M.tb is required.

Epstein-Barr virus-induced gene 3 (EBI3) can mediate IL-6 trans-signaling

Epstein-Barr virus-induced gene 3 (EBI3) is a subunit of the composite cytokines IL-27 and IL-35. Both have beneficial functions or effects in models of infectious and autoimmune diseases. This suggests that administration of EBI3 could be therapeutically useful by binding free p28 and p35 to generate IL-27 and IL-35. IL-27- and IL-35-independent functions of EBI3 could compromise its therapeutic uses. We therefore assessed the effects of EBI3 on cytokine receptor-expressing cells. We observed that EBI3 activates STAT3 and induces the proliferation of the IL-6-dependent B9 mouse plasmacytoma cell line. Analyses using blocking mAbs and Ba/F3 transfectants expressing gp130 indicate that EBI3 activity was linked to its capacity to mediate IL-6 trans-signaling, albeit less efficiently than soluble IL-6Rα. In line with this interpretation, co-immunoprecipitation and SPR experiments indicated that EBI3 binds IL-6. An important pro-inflammatory function of IL-6 trans-signaling is to activate blood vessel endothelial cells. We observed that EBI3 in combination with IL-6 could induce the expression of chemokines by human venal endothelial cells. Our results indicate that EBI3 can promote pro-inflammatory IL-6 functions by mediating trans-signaling. These unexpected observations suggest that use of EBI3 as a therapeutic biologic for autoimmune diseases will likely require co-administration of soluble gp130 to prevent the side effects associated with IL-6 trans-signaling. Together with previous studies that demonstrated activation of IL-6R by p28 (IL-30), new findings further suggest a complex interrelation between IL-27 and IL-6.

Preoperative Serum IL-12p40 Is a Potential Predictor of Kasai Portoenterostomy Outcome in Infants with Biliary Atresia

The standard-of-care treatment for biliary atresia (BA) is surgical restoration of bile flow by Kasai portoenterostomy. We aimed to study serum interleukin- (IL-) 12p40, a natural antagonist for the proinflammatory IL-12p70, and its relation to surgical outcomes of BA. The study included 75 infants with neonatal cholestasis: BA group (n = 25), non-BA cholestasis group (n = 30), and neglected BA group (n = 20), in addition to thirty healthy neonates serving as controls. IL-12p40 was measured by ELISA in all individuals and a second assessment was performed 3 months postoperatively in the BA group. The surgical outcomes were classified as successful (bilirubin ≤ 2 mg/dl) or failed (bilirubin > 2 mg/dl). IL-12p40 was higher in BA compared to that in the non-BA and control groups (P values were 0.036 and <0.0001, resp.) but comparable to that in the neglected BA group. Preoperative IL-12p40 levels in BA patients were significantly higher in successful Kasai compared with failed Kasai and a cutoff level of 547.47 pg/ml could predict the successful outcome with 87.5% sensitivity and 82.4% specificity. Three-month postoperative IL-12p40 tended to decrease in both the successful and failed groups. In conclusion, preoperative serum IL-12p40 is a potential predictor of Kasai outcome. Serial postoperative measurements may anticipate the failure of an initially successful operation, hence the need for liver transplantation.

Involvement of interleukin‑23 induced by Porphyromonas endodontalis lipopolysaccharide in osteoclastogenesis

Periapical lesions are characterized by the destruction of periapical bone, and occur as a result of local inflammatory responses to root canal infection by microorganisms including Porphyromonas endodontalis (P. endodontalis). P. endodontalis and its primary virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical lesions and alveolar bone loss. Interleukin-23 (IL-23) is critical in the initiation and progression of periodontal disease via effects on peripheral bone metabolism. The present study investigated the expression of IL-23 in tissue where a periapical lesion was present, and the effect of P. endodontalis LPS on the expression of IL-23 in periodontal ligament (PDL) cells. Reverse transcription- quantitative polymerase chain reaction and immunohistochemistry revealed increased levels of IL-23 expression in tissue with periapical lesions compared with healthy PDL tissue. Treatment with P. endodontalis LPS increased the expression of IL-23 in the SH-9 human PDL cell line. BAY11-7082, a nuclear factor κB inhibitor, suppressed P. endodontalis LPS-induced IL-23 expression in SH-9 cells. Treatment of RAW264.7 cells with conditioned medium from P. endodontalis LPS-treated SH-9 cells promoted osteoclastogenesis. By contrast, RAW264.7 cells treated with conditioned medium from IL-23-knockdown SH-9 cells underwent reduced levels of osteoclastogenesis. The results of the present study indicated that the expression of IL-23 in PDL cells induced by P. endodontalis LPS treatment may be involved in the progression of periapical lesions via stimulation of the osteoclastogenesis process.

A potentially protective role of IL-18 Binding Protein in HIV-infected Long-Term Non-Progressors

An imbalance between IL-18 and its antagonist, IL-18 Binding Protein, occurs in the circulation of HIV-infected individuals. We show here for the first time that HIV-infected Long Term Non-Progressors (LTNPs) do not develop this imbalance, and maintain normal levels of IL-18BP in the circulation. Their circulating levels of the antagonist correlate negatively with viral loads and show a positive trend with CD4+ T cells counts. The maintenance of normal production of IL-18BP may contribute, at least in part, to the ability of LTNPs to delay AIDS progression.

IL-12p40/IL-10 Producing preCD8α/Clec9A+ Dendritic Cells Are Induced in Neonates upon Listeria monocytogenes Infection

Infection by Listeria monocytogenes (Lm) causes serious sepsis and meningitis leading to mortality in neonates. This work explored the ability of CD11c^high lineage DCs to induce CD8⁺ T-cell immune protection against Lm in mice before 7 days of life, a period symbolized by the absence of murine IL-12p70-producing CD11c^highCD8α⁺ dendritic cells (DCs). We characterized a dominant functional Batf3-dependent precursor of CD11c^high DCs that is Clec9A⁺CD205⁺CD24⁺ but CD8α^- at 3 days of life. After Lm-OVA infection, these pre-DCs that cross-present Ag display the unique ability to produce high levels of IL-12p40 (not IL-12p70 nor IL-23), which enhances OVA-specific CD8⁺ T cell response, and regulatory IL-10 that limits OVA-specific CD8⁺ T cell response. Targeting these neonatal pre-DCs for the first time with a single treatment of anti-Clec9A-OVA antibody in combination with a DC activating agent such as poly(I:C) increased the protection against later exposure to the Lm-OVA strain. Poly(I:C) was shown to induce IL-12p40 production, but not IL-10 by neonatal pre-DCs. In conclusion, we identified a new biologically active precursor of Clec9A⁺ CD8α^- DCs, endowed with regulatory properties in early life that represents a valuable target to augment memory responses to vaccines.

Lm is a gram-positive food-borne pathogen that is the ethiological agent of listeriosis, a worldwide disease reported most frequently in developed countries. It can cause spontaneous septic abortions, fatal meningitis or encephalitis in immunocompromised and pregnant individuals. The murine model of systemic Lm infection has been demonstrated as a useful model to understand host resistance to intracellular pathogens. Neonates are highly susceptible to infections such as Lm, and display low responses to vaccines requiring IFN-γ producing T cells. In the present study, we characterized in murine neonates a precursor of conventional dendritic cells that is able to produce IL-12p40 and IL-10 cytokines and to modulate the development of the adaptive immune response, more particularly the CD8⁺ T cell response upon exposure to Lm. By targeting Lm-associated antigens to these conventional dendritic cell precursors in neonates, we succeeded to confer a partial protection to a lethal dose of Lm at the adult stage. Our study provides new insights into our understanding of the innate immune response to infections in early life and will help to design new vaccine strategies in newborns.

Inflammation and Elevation of Interleukin-12p40 in Patients with Schizophrenia

Schizophrenia is a serious mental illness with chronic symptoms and significant impairment in psychosocial functioning, which suggests that it likely has neurodegenerative characteristics. Inflammatory markers such as pro-inflammatory cytokines are well-known etiological contributors for psychiatric disorders, including schizophrenia. Although, the role of inflammation in schizophrenia is becoming evident, the number of studies in this area is relatively scarce, especially in Lebanon, and increased procedural thoroughness is needed. Cytokines play a key role in the activation of the immune system and strongly influence neurotransmission. Previous investigation of plasma levels showed dysregulation of interleukin (IL)-12. However, genotypical variations of this interleukin have not been investigated for patients with schizophrenia yet. Thus, in this paper, we aimed to compute and assess IL-12p40 levels in the sera of individuals with schizophrenia from different provinces in Lebanon and compare it to controls. Healthy subjects comprised 60 individuals with a male/female (M/F) ratio of 31/29, whereas patients with schizophrenia consisted of 63 subjects with an M/F ratio of 30/33. The mean age for healthy controls was 30 years, whereas that for patients with schizophrenia was 35 years. A standardized enzyme-linked immunosorbent assay (ELISA) technique was used to measure the concentration of IL-12p40 in all collected sera (n = 123). The mean IL-12p40 levels in patients with schizophrenia were significantly higher than in healthy controls (p = 0.002). Healthy females had a significantly higher concentration of IL-12p40 than healthy males (p = 0.009). Female patients with schizophrenia had significantly higher concentrations of IL-12p40 than their male counterparts (p < 0.001), healthy females (p = 0.018), and healthy males (p < 0.001), respectively. Male patients with schizophrenia had significantly higher concentrations of IL-12p40 than healthy males (p = 0.023). The study's results suggest that IL-12p40 has a putative role as a potential marker in schizophrenia and that its elevation may participate in its pathogenesis. IL-12p40 may be included in a panel to be evaluated in the sera of patients with schizophrenia and an appreciation of its independent function is important for improving our understanding of both protective and pathogenic immune responses. Future research should aim to assess this interleukin and understand its role in other mental illnesses that share a similar etiology to schizophrenia.

Immunocytokines: a novel class of products for the treatment of chronic inflammation and autoimmune conditions

Antibody-cytokine fusion proteins, often referred to as immunocytokines, represent a novel class of biopharmaceutical agents that combine the disease-homing activity of certain antibodies with the immunomodulatory properties of cytokine payloads. Originally, immunocytokines were mainly developed for cancer therapy applications. More recently, however, the use of anti-inflammatory cytokines for the treatment of chronic inflammatory conditions and to treat autoimmune diseases has been considered. This review analyzes basic principles in the design of immunocytokines and describes the most advanced products in preclinical and clinical development.

Alternatively Spliced EDA Domain of Fibronectin Is a Target for Pharmacodelivery Applications in Inflammatory Bowel Disease

The antibody-based pharmacodelivery of cytokines to sites of disease has been extensively studied for various indications but not for the treatment of inflammatory bowel diseases. Here, we report that the alternatively spliced EDA domain of fibronectin, a marker of angiogenesis and of tissue remodeling, is expressed in the dextran sodium sulfate mouse model of colitis and in patients with inflammatory bowel conditions, while being virtually undetectable in most normal adult tissues. Radiolabeled preparations of the F8 antibody, specific to the EDA domain of fibronectin, were shown to selectively localize to sites of inflammation in mice with colitis, as revealed by autoradiographic analysis. Fusion proteins of the F8 antibody with various murine payloads (interleukin-4, the p40 subunit of interleukin-12, interleukin-13) were administered to mice with colitis. IL12p40-F8 mediated an anti-inflammatory activity, which was comparable with the one of cyclosporine, whereas F8-IL4 did not inhibit colitis and F8-IL13 worsened the inflammatory conditions.

Insights into IL-23 biology: From structure to function

Interleukin (IL-)23 is a central cytokine controlling TH17 development. Overshooting IL-23 signaling contribute to autoimmune diseases. Moreover, GWAS studies have identified several SNPs within the IL-23 receptor, which are associated with autoimmune diseases. IL-23 is a member of the IL-12-type cytokine family and consists of IL-23p19 and p40. Within the IL-12 family, IL-12 and IL-23 share the p40 cytokine subunit and the IL-12Rβ1 as one chain of the receptor complex. For signaling, IL-23 triggers heterodimerization of IL-12Rβ1 and the IL-23R. Subsequently, signal transduction pathways including JAK/STAT, MAPK and PI3K are activated. Most studies have investigated the biological relevance of IL-23 in the development of TH17 cells and autoimmunity, whereas less is known about the molecular context of IL-23 biology. Therefore, we focused on IL-23 receptor complex assembly, signal transduction and functional relevance of IL-23R SNPs in the context of IL-23-inhibitory principles.

Non-canonical interleukin 23 receptor complex assembly: p40 protein recruits interleukin 12 receptor β1 via site II and induces p19/interleukin 23 receptor interaction via site III

IL-23, composed of the cytokine subunit p19 and the soluble α receptor subunit p40, binds to a receptor complex consisting of the IL-23 receptor (IL-23R) and the IL-12 receptor β1 (IL-12Rβ1). Complex formation was hypothesized to follow the "site I-II-III" architectural paradigm, with site I of p19 being required for binding to p40, whereas sites II and III of p19 mediate binding to IL-12Rβ1 and IL-23R, respectively. Here we show that the binding mode of p19 to p40 and of p19 to IL-23R follow the canonical site I and III paradigm but that interaction of IL-23 to IL-12Rβ1 is independent of site II in p19. Instead, binding of IL-23 to the cytokine binding module of IL-12Rβ1 is mediated by domains 1 and 2 of p40 via corresponding site II amino acids of IL-12Rβ1. Moreover, domains 2 and 3 of p40 were sufficient for complex formation with p19 and to induce binding of p19 to IL-23R. The Fc-tagged fusion protein of p40_D2D3/p19 did, however, not act as a competitive IL-23 antagonist but, at higher concentrations, induced proliferation via IL-23R but independent of IL-12Rβ1. On the basis of our experimental validation, we propose a non-canonical topology of the IL-23·IL-23R·IL-12Rβ1 complex. Furthermore, our data help to explain why p40 is an antagonist of IL-23 and IL-12 signaling and show that site II of p19 is dispensable for IL-23 signaling.

Recombinant p35 from bacteria can form Interleukin (IL-)12, but Not IL-35

The Interleukin (IL)-12 family contains several heterodimeric composite cytokines which share subunits among each other. IL-12 consists of the subunits p40 (shared with IL-23) and p35. p35 is shared with the composite cytokine IL-35 which comprises of the p35/EBI3 heterodimer (EBI3 shared with IL-27). IL-35 signals via homo- or heterodimers of IL-12Rβ2, gp130 and WSX-1, which are shared with IL-12 and IL-27 receptor complexes, respectively. p35 was efficiently secreted in complex with p40 as IL-12 but not with EBI3 as IL-35 in several transfected cell lines tested which complicates the analysis of IL-35 signal transduction. p35 and p40 but not p35 and EBI3 form an inter-chain disulfide bridge. Mutation of the responsible cysteine residue (p40_C197A) reduced IL-12 formation and activity only slightly. Importantly, the p40_C197A mutation prevented the formation of antagonistic p40 homodimers which enabled the in vitro reconstitution of biologically active IL-12 with p35 produced in bacteria (p35_bac). Reconstitution of IL-35 with p35_bac and EBI3 did, however, fail to induce signal transduction in Ba/F3 cells expressing IL-12Rβ2 and gp130. In summary, we describe the in vitro reconstitution of IL-12, but fail to produce recombinant IL-35 by this novel approach.

Altered serum cytokine signature in common variable immunodeficiency

PURPOSE

Common variable immunodeficiency (CVID) is the most frequent form of primary symptomatic hypogammaglobulinemia. CVID patients display a number of abnormalities in lymphocyte subpopulations including chronic T-cell activation and decreased numbers of circulating CD4(+) T cells and NK cells. We and others have recently shown that CVID is associated with increased concentration of soluble CD14 (sCD14) and other factors indicating limited microbial translocation.

METHODS

To address the mechanisms of chronic immune activation in CVID, we performed a detailed analysis of cytokine serum levels in 36 patients with CVID, 52 patients with selective IgA deficiency (IgAD), and 56 healthy volunteers.

RESULTS

We show that CVID is associated with elevated serum levels of CXCL-10/IP-10, IL-1R antagonist, TNF-α, IL-10, IL-12 (p40), CCL-2/MCP-1, G-CSF, and CCL-11/eotaxin. The detected cytokine signature is consistent with an ongoing activation of cells of myeloid lineage. In contrast, the levels of cytokines typically produced by CD4(+) T helper cells of Th1 (IFN-γ, IL-2), Th2 (IL-9, IL-13), and Th17 (IL-17) subtypes were suppressed in CVID patients compared to healthy donors.

CONCLUSIONS

Presented data suggest that the altered cytokine profile observed in patients with CVID may be attributed to the activation of monocyte-macrophage and granulocyte lineages, possibly driven by the translocation of bacterial components across the gastrointestinal or respiratory tracts mucosal barrier.

Smart adjuvants

Although vaccine adjuvants have been used for almost a century, alum is the only adjuvant licensed by the US FDA for human vaccine use. Many adjuvants studied to date have generalized inflammatory properties and lack specificity in terms of targeting immune compartments and cell populations. Indeed, such adjuvants have often been crude in formulation, their effects usually restricted to T-helper 2-type immunity and their use limited owing to inherent toxicity. However, recent advances in immunology have resulted in a number of potential adjuvant candidates that are able to modulate the immune response in a more controlled and specific manner. These novel adjuvants are attractive for inclusion in current and future vaccine strategies since they have better-defined mechanisms of action. In this article, we review several compounds that target specific immune components, such as cells, receptors or signaling pathways, and have termed such reagents 'smart adjuvants'.

High intestinal and systemic levels of interleukin-23/T-helper 17 pathway in Chinese patients with inflammatory bowel disease

Interleukin-23/T-helper 17 (IL-23/Th17) pathway plays a key role in the pathogenesis of inflammatory bowel disease (IBD), but little is known about its expression in Chinese population. In this study, we investigated the mRNA and protein levels of IL-12p40, tumor necrosis factor-like cytokine 1A (TL1A), Janus kinase 2 (JAK2), and IL-23R both locally and systemically in Chinese IBD patients. Our results indicated that the mRNA levels of IL-12p40 and TL1A were increased in ulcerative colitis (UC) patients. Furthermore, serum IL-12p40 and TL1A levels were higher in active UC patients, especially in patients with disease course less than 1.25 years or initial onset. No correlation was found between the genotype and serum levels of IL-12p40 or TL1A in UC patients. Additionally, the mRNA and protein expression of JAK2 and IL-23R were increased in UC and Crohn's disease (CD) patients. Taken together, our results provided evidence that IL-23/Th17 pathway genes may represent important biomarkers of active stage of IBD and serve as novel therapeutic targets for IBD in Chinese population.

Oncolytic adenovirus expressing IL-23 and p35 elicits IFN-γ- and TNF-α-co-producing T cell-mediated antitumor immunity

Cytokine immunogene therapy is a promising strategy for cancer treatment. Interleukin (IL)-12 boosts potent antitumor immunity by inducing T helper 1 cell differentiation and stimulating cytotoxic T lymphocyte and natural killer cell cytotoxicity. IL-23 has been proposed to have similar but not overlapping functions with IL-12 in inducing Th1 cell differentiation and antitumor immunity. However, the therapeutic effects of intratumoral co-expression of IL-12 and IL-23 in a cancer model have yet to be investigated. Therefore, we investigated for the first time an effective cancer immunogene therapy of syngeneic tumors via intratumoral inoculation of oncolytic adenovirus co-expressing IL-23 and p35, RdB/IL23/p35. Intratumoral administration of RdB/IL23/p35 elicited strong antitumor effects and increased survival in a murine B16-F10 syngeneic tumor model. The levels of IL-12, IL-23, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) were elevated in RdB/IL23/p35-treated tumors. Moreover, the proportion of regulatory T cells was markedly decreased in mice treated with RdB/IL23/p35. Consistent with these data, mice injected with RdB/IL23/p35 showed massive infiltration of CD4⁺ and CD8⁺ T cells into the tumor as well as enhanced induction of tumor-specific immunity. Importantly, therapeutic mechanism of antitumor immunity mediated by RdB/IL23/p35 is associated with the generation and recruitment of IFN-γ- and TNF-α-co-producing T cells in tumor microenvironment. These results provide a new insight into therapeutic mechanisms of IL-12 plus IL-23 and provide a potential clinical cancer immunotherapeutic agent for improved antitumor immunity.

Elevated macrophage inflammatory protein 1α and interleukin-17 production in an experimental asthma model infected with respiratory syncytial virus

BACKGROUND

Respiratory syncytial virus (RSV) infection is associated with both the development and exacerbation of bronchial asthma. We examined eosinophil infiltration and the cytokine profiles of both airway and peripheral blood in antigen-sensitized mice infected with RSV to investigate the pathogenesis of exacerbations of asthma due to RSV infection.

METHODS

Ovalbumin (OVA)-sensitized mice were challenged by OVA inhalation 3 times and then infected with RSV [10(5) TCID50 (50% of tissue culture infectious dose)/25 g body weight] or mock infection immediately after the last challenge. Animals from each group, namely, the control (PBS instead of OVA inhalation plus mock infection), RSV (PBS plus RSV), OVA (OVA plus mock) and OVA/RSV (OVA plus RSV) were analyzed. Analysis included evaluation of airway responsiveness to methacholine, pathological findings in the airway by hematoxylin and eosin (HE) and Luna staining, bronchoalveolar fluid (BALF) and peripheral leukocytes counts, and concentrations of multiple cytokines/chemokines in both BALF and serum.

RESULTS

Airway responsiveness was significantly enhanced in the OVA and OVA/RSV groups compared with the control group. Levels of tissue and BALF eosinophils were higher in the OVA and OVA/RSV groups than in the RSV or control group. Significantly higher levels of macrophage inflammatory protein (MIP)-1α in BALF were observed in the OVA/RSV group compared with the 3 other groups. Production of serum IL-17 was also significantly elevated in the OVA/RSV group compared with the control or OVA group.

CONCLUSIONS

These findings suggest that MIP-1α and IL-17 may play important roles in acute exacerbation of asthma induced by RSV in an animal model.

Intravenous delivery of HIV-based lentiviral vectors preferentially transduces F4/80+ and Ly-6C+ cells in spleen, important target cells in autoimmune arthritis

Antigen presenting cells (APCs) play an important role in arthritis and APC specific gene therapeutic targeting will enable intracellular modulation of cell activity. Viral mediated overexpression is a potent approach to achieve adequate transgene expression levels and lentivirus (LV) is useful for sustained expression in target cells. Therefore, we studied the feasibility of lentiviral mediated targeting of APCs in experimental arthritis. Third generation VSV-G pseudotyped self-inactivating (SIN)-LV were injected intravenously and spleen cells were analyzed with flow cytometry for green fluorescent protein (GFP) transgene expression and cell surface markers. Collagen-induced arthritis (CIA) was induced by immunization with bovine collagen type II in complete Freund's adjuvant. Effect on inflammation was monitored macroscopically and T-cell subsets in spleen were analyzed by flow cytometry. Synovium from arthritic knee joints were analyzed for proinflammatory cytokine expression. Lentiviruses injected via the tail vein preferentially infected the spleen and transduction peaks at day 10. A dose escalating study showed that 8% of all spleen cells were targeted and further analysis showed that predominantly Ly6C+ and F4/80+ cells in spleen were targeted by the LV. To study the feasibility of blocking TAK1-dependent pathways by this approach, a catalytically inactive mutant of TAK1 (TAK1-K63W) was overexpressed during CIA. LV-TAK1-K63W significantly reduced incidence and arthritis severity macroscopically. Further histological analysis showed a significant decrease in bone erosion in LV-TAK1-K63W treated animals. Moreover, systemic Th17 levels were decreased by LV-TAK1-K63W treatment in addition to diminished IL-6 and KC production in inflamed synovium. In conclusion, systemically delivered LV efficiently targets monocytes and macrophages in spleen that are involved in autoimmune arthritis. Moreover, this study confirms efficacy of TAK1 targeting in arthritis. This approach may provide a valuable tool in targeting splenic APCs, to unravel their role in autoimmune arthritis and to identify and validate APC specific therapeutic targets.

Cerebrospinal fluid IL-12p40, CXCL13 and IL-8 as a combinatorial biomarker of active intrathecal inflammation

Diagnosis and management of the neuroinflammatory diseases of the central nervous system (CNS) are hindered by the lack of reliable biomarkers of active intrathecal inflammation. We hypothesized that measuring several putative inflammatory biomarkers simultaneously will augment specificity and sensitivity of the biomarker to the clinically useful range. Based on our pilot experiment in which we measured 18 inflammatory biomarkers in 10-fold concentrated cerebrospinal fluid (CSF) derived from 16 untreated patients with highly active multiple sclerosis (MS) we selected a combination of three CSF biomarkers, IL-12p40, CXCL13 and IL-8, for further validation.Concentrations of IL-12p40, CXCL13 and IL-8 were determined in a blinded fashion in CSF samples from an initial cohort (n = 72) and a confirmatory cohort (n = 167) of prospectively collected, untreated subjects presenting for a diagnostic work-up of possible neuroimmunological disorder. Diagnostic conclusion was based on a thorough clinical workup, which included laboratory assessment of the blood and CSF, neuroimaging and longitudinal follow-up. Receiver operating characteristic (ROC) curve analysis in conjunction with principal component analysis (PCA), which was used to combine information from all three biomarkers, assessed the diagnostic value of measured biomarkers.Each of the three biomarkers was significantly increased in MS and other inflammatory neurological disease (OIND) in comparison to non-inflammatory neurological disorder patients (NIND) at least in one cohort. However, considering all three biomarkers together improved accuracy of predicting the presence of intrathecal inflammation to the consistently good to excellent range (area under the ROC curve = 0.868-0.924).Future clinical studies will determine if a combinatorial biomarker consisting of CSF IL-12p40, CXCL13 and IL-8 provides utility in determining the presence of active intrathecal inflammation in diagnostically uncertain cases and in therapeutic development and management.

Delivery of IL-12p40 ameliorates DSS-induced colitis by suppressing IL-17A expression and inflammation in the intestinal mucosa

IL-12p40 homodimer is a natural antagonist of IL-12 and IL-23, which are potent pro-inflammatory cytokines required for Th1 and Th17 immune responses, respectively. It has been reported that Th17 response is involved in inflammatory bowel disease (IBD), a chronic disorder of the digestive system with steadily increasing incidence. Here, we investigated the effects of IL-12p40 delivered via recombinant adenovirus (rAd/IL-12p40) or mesenchymal stem cells (MSC/IL-12p40) in a dextran sulfate sodium salt (DSS)-induced colitis model. Injection of rAd/IL-12p40 or MSC/IL-12p40 efficiently attenuated colitis symptoms and tissue damage, leading to an increased survival rate. Moreover, IL-12p40 delivery suppressed IL-17A, but enhanced IFN-γ production from mesenteric lymph node cells, supporting the preferential suppression of IL-23 by IL-12p40 homodimer in vitro and the suppression of Th17 responses in vivo. Our results demonstrate that IL-12p40 delivery ameliorates DSS-induced colitis by suppressing IL-17A production and inflammation in the intestinal mucosa, providing an effective new therapeutic strategy for IBDs.

Plasticity and cross-talk of interleukin 6-type cytokines

Interleukin (IL)-6-type cytokines are critically involved in health and disease. The duration and strength of IL-6-type cytokine-mediated signaling is tightly regulated to avoid overshooting activities. Here, molecular mechanisms of inter-familiar cytokine cross-talk are reviewed which regulate dynamics and strength of IL-6 signal transduction. Both plasticity and cytokine cross-talk are significantly involved in pro- and anti-inflammatory/regenerative properties of IL-6-type cytokines. Furthermore, we focus on IL-6-type cytokine/cytokine receptor plasticity and cross-talk exemplified by the recently identified composite cytokines IL-30/IL-6R and IL-35, the first inter-familiar IL-6/IL-12 family member. The complete understanding of the intra- and extracellular cytokine networks will aid to develop novel tailor-made therapeutic strategies with reduced side effects.

Airway epithelial regulation of allergic sensitization in asthma

While many of the contributing cell types and mediators of allergic asthma are known, less well understood are the factors that influence the development of allergic responses that lead to the development of allergic asthma. As the first airway cell type to respond to inhaled factors, the epithelium orchestrates downstream interactions between dendritic cells (DCs) and CD4⁺ T cells that quantitatively and qualitatively dictate the degree and type of the allergic asthma phenotype, making the epithelium of critical importance for the genesis of allergies that later manifest in allergic asthma. Amongst the molecular processes of critical importance in airway epithelium is the transcription factor, nuclear factor-kappaB (NF-κB). This review will focus primarily on the genesis of pulmonary allergies and the participation of airway epithelial NF-κB activation therein, using examples from our own work on nitrogen dioxide (NO₂) exposure and genetic modulation of airway epithelial NF-κB activation. In addition, the mechanisms through which Serum Amyloid A (SAA), an NF-κB-regulated, epithelial-derived mediator, influences allergic sensitization and asthma severity will be presented. Knowledge of the molecular and cellular processes regulating allergic sensitization in the airways has the potential to provide powerful insight into the pathogenesis of allergy, as well as targets for the prevention and treatment of asthma.

Interleukin-23: as a drug target for autoimmune inflammatory diseases

Interleukin-23 (IL-23) is a member of the IL-12 family of cytokines with pro-inflammatory properties. Its ability to potently enhance the expansion of T helper type 17 (Th17) cells indicates the responsibility for many of the inflammatory autoimmune responses. Emerging data demonstrate that IL-23 is a key participant in central regulation of the cellular mechanisms involved in inflammation. Both IL-23 and IL-17 form a new axis through Th17 cells, which has evolved in response to human diseases associated with immunoactivation and immunopathogeny, including bacterial or viral infections and chronic inflammation. Targeting of IL-23 or the IL-23 receptor or IL-23 axis is a potential therapeutic approach for autoimmune diseases including psoriasis, inflammatory bowel disease, rheumatoid arthritis and multiple sclerosis. The current review focuses on the immunobiology of IL-23 and summarizes the most recent findings on the role of IL-23 in the pre-clinical and ongoing clinical studies.

Interleukin-27 inhibits vaccine-enhanced pulmonary disease following respiratory syncytial virus infection by regulating cellular memory responses

Respiratory syncytial virus (RSV) is the most important cause of lower respiratory tract disease in young children. In the 1960s, infants vaccinated with formalin-inactivated RSV developed a more severe disease characterized by excessive inflammatory immunopathology in lungs upon natural RSV infection. The fear of causing the vaccine-enhanced disease (VED) is an important obstacle for development of safe and effective RSV vaccines. The recombinant vaccine candidate G1F/M2 immunization also led to VED. It has been proved that cellular memory induced by RSV vaccines contributed to VED. Interleukin-27 (IL-27) and IL-23 regulate Th1, Th17, and/or Th2 cellular immune responses. In this study, mice coimmunized with pcDNA3-IL-27 and G1F/M2 were fully protected and, importantly, did not develop vaccine-enhanced inflammatory responses and immunopathology in lungs after RSV challenge, which was correlated with moderate Th1-, suppressed Th2-, and Th17-like memory responses activated by RSV. In contrast, G1F/M2- or pcDNA3-IL-23+G1F/M2-immunized mice, in which robust Th2- and Th17-like memory responses were induced, developed enhanced pulmonary inflammation and severe immunopathology. Mice coimmunized with G1F/M2 and the two cytokine plasmids exhibited mild inflammatory responses as well as remarkable Th1-, suppressed Th2-, and Th17-like memory responses. These results suggested that Th1-, Th2-, and Th17-like memory responses and, in particular, excessive Th2- and Th17-like memory responses were closely associated with VED; IL-27 may inhibit VED following respiratory syncytial virus infection by regulating cellular memory responses.

Severe malarial anemia: innate immunity and pathogenesis

Greater than 80% of malaria-related mortality occurs in sub-Saharan Africa due to infections with Plasmodium falciparum. The majority of P. falciparum-related mortality occurs in immune-naïve infants and young children, accounting for 18% of all deaths before five years of age. Clinical manifestations of severe falciparum malaria vary according to transmission intensity and typically present as one or more life-threatening complications, including: hyperparasitemia; hypoglycemia; cerebral malaria; severe malarial anemia (SMA); and respiratory distress. In holoendemic transmission areas, SMA is the primary clinical manifestation of severe childhood malaria, with cerebral malaria occurring only in rare cases. Mortality rates from SMA can exceed 30% in pediatric populations residing in holoendemic transmission areas. Since the vast majority of the morbidity and mortality occurs in immune-naïve African children less than five years of age, with SMA as the primary manifestation of severe disease, this review will focus primarily on the innate immune mechanisms that govern malaria pathogenesis in this group of individuals. The pathophysiological processes that contribute to SMA involve direct and indirect destruction of parasitized and non-parasitized red blood cells (RBCs), inefficient and/or suppression of erythropoiesis, and dyserythropoiesis. While all of these causal etiologies may contribute to reduced hemoglobin (Hb) concentrations in malaria-infected individuals, data from our laboratory and others suggest that SMA in immune-naïve children is characterized by a reduced erythropoietic response. One important cause of impaired erythroid responses in children with SMA is dysregulation in the innate immune response. Phagocytosis of malarial pigment hemozoin (Hz) by monocytes, macrophages, and neutrophils is a central factor for promoting dysregulation in innate inflammatory mediators. As such, the role of P. falciparum-derived Hz (PfHz) in mediating suppression of erythropoiesis through its ability to cause dysregulation in pro- and anti-inflammatory cytokines, growth factors, chemokines, and effector molecules is discussed in detail. An improved understanding of the etiological basis of suppression of erythropoietic responses in children with SMA may offer the much needed therapeutic alternatives for control of this global disease burden.

The endothelin axis stimulates the expression of pro-inflammatory cytokines and pro-migratory molecules in breast cancer

We investigated the effects of the endothelin-1 (ET-1) receptor dual antagonist (Bosentan®) on the inflammatory cytokines and the chemoattractant molecules associated with breast cancer growth and the development of tumor infiltration in bone explants. Immunocompetent mice implanted with the murine mammary carcinoma 4T1 cells in a skin-fold chamber and treated with Bosentan® had reduced tumor growth (p < .05). ET-1 promoted the secretion of the anti-inflammatory soluble tumor necrosis factor (TNF) receptor and IL12 p40 in vitro. The Bosentan® treatment in vivo was associated with a local increase of the anti-inflammatory IL-1α cytokine concentration and decrease of the pro-inflammatory TNF-α and IL-17 cytokine concentrations (p < .05).

Human breast tumor cells express IL-10 and IL-12p40 transcripts and proteins, but do not produce IL-12p70

IL-10 transcripts were expressed in 14/15 primary breast adenocarcinomas and in 5/8 established breast tumor lines. Immunohistochemistry and immunoprecipitation from lysates and supernatants revealed that established breast tumor lines produced IL-10 protein. Immunohistochemistry revealed that IL-10 is localized to tumor cells of primary breast adenocarcinomas and to occasional infiltrating MNC. Established breast tumor cell lines expressed IL-12p40 transcripts (6/8) and protein (4/7) and IL-12p35 transcripts (6/7). Using two sandwich ELISAs, specific, respectively, for IL-12p40 and IL-12p70 proteins, we demonstrated that established breast tumor cell lines produce IL-12p40 monomer/homodimer, but not IL-12p70. Positive staining for IL-12p70 in primary breast adenocarcinomas was found only in MNC infiltrating the tumor while tumor cells were negative. IL-12p40 homodimer/monomer inhibit as antagonists IL-12 or IL-23, although they may also act as agonists and positive regulators. Also, primary breast adenocarcinomas (15/15) and established breast tumor cell lines (6/8) expressed TGF-β1 transcripts. IL-10, IL-12p40 and TGF-β1 may inhibit substantially the anti-tumor immune response.

A novel class of anti-IL-12p40 antibodies: potent neutralization via inhibition of IL-12-IL-12Rβ2 and IL-23-IL-23R

While current therapeutic antibodies bind to IL-12 and IL-23 and inhibit their binding to IL-12Rβ1, we describe a novel antibody, termed 6F6, that binds to IL-12 and IL-23 and inhibits the interaction of IL-12 and IL-23 with their cognate signalling receptors IL-12Rβ2 and IL23R. This antibody does not affect the natural inhibition of the IL-12/23 pathway by the antagonists monomeric IL-12p40 and IL-12p80, which suggests that a dual antagonist system is possible. We have mapped the epitope of 6F6 to domain 3 of the p40 chain common to IL-12 and IL-23 and demonstrate that an antibody bound to this epitope is sufficient to inhibit engagement of the signalling receptors. Antibodies with this unique mechanism of inhibition are potent inhibitors of IL-12 induced IFN-γ production and IL-23 induced IL-17 production in vitro, and in an in vivo model of psoriasis, treatment with a humanized variant of this antibody, h6F6, reduced the inflammatory response, resulting in decreased epidermal hyperplasia. We believe that this new class of IL-12/23 neutralising antibodies has the potential to provide improved potency and efficacy as anti-inflammatory agents, particularly in diseases characterized by an overproduction of IL-12.

High IL-12 p35 and IL-23 p19 mRNA expression is associated with superior outcome in ovarian cancer

OBJECTIVE

Interleukin-12 (IL-12) and IL-23 share a common p40 subunit that is either covalently linked to the p35 (IL-12) or to the p19 subunit (IL-23). Data from genetic animal models suggest that in contrast to the central role of IL-12 for tumor immune-surveillance, its close relative IL-23 rather promotes tumor growth. It was the aim of this project to evaluate the clinical significance of these findings.

METHODS

Intra-tumoral mRNA expression levels of the IL-12 specific subunit p35 and the IL-23 specific subunit p19 were quantified in ovarian cancer specimens (n=112) and control samples from healthy ovary tissue specimens (n=20) and correlated with clinical outcome.

RESULTS

Both cytokines were expressed at higher levels in ovarian cancer specimens as compared to healthy controls. p35 and p19 mRNA expression levels positively correlated in both malignant and healthy ovarian tissue. High p35 and p19 mRNA expression was associated with a significant better overall survival (OS) in the overall cohort. p35 mRNA correlated with superior outcome in advanced stage disease (FIGO III/IV), whereas the effect of high p19 mRNA expression was pre-dominant in early stage disease (FIGO I/II). Multivariate analysis revealed that p35 mRNA expression represents an independent predictor for OS but not for PFS in ovarian cancer.

CONCLUSION

In contrast to the recently proposed opposing roles of IL-12 and IL-23 for cancer growth and progression in rodents, our data from a large patient cohort rather suggest that high intra-tumoral expression levels of p35 mRNA and p19 mRNA are associated with a superior clinical outcome.

Role of interleukin-12 family cytokines in the cellular response to mycobacterial disease

Interleukin (IL)-12 is a multifunctional cytokine acting as a key regulator of cell-mediated immune responses through the differentiation of naïve CD4+ T cells into type 1 helper T cells (Th1) producing interferon-gamma. As our knowledge of IL-12 family members is rapidly growing, it will be important to specify their involvement in the regulation of mycobacterial infection. This article is a review of the current knowledge regarding the functions of the IL-12 family cytokines in the immune host defense system against mycobacteria. Specifically, this review aims to describe recent scientific evidence concerning the protective role of some members of the IL-12 family cytokines for the control of mycobacterial infection, as well as to summarize knowledge of the potential use of the IL-12 family members as potent adjuvants in the prevention and treatment of mycobacterial infectious diseases. In addition, recent data supporting the importance of the IL-12 family members in mycobacterial diseases in relation to Th17 function are discussed. This examination will help to improve our understanding of the immune response to mycobacterial infection and also improve vaccine design and immunotherapeutic intervention against tuberculosis.

The secreted form of p28 subunit of interleukin (IL)-27 inhibits biological functions of IL-27 and suppresses anti-allogeneic immune responses

Interleukin-27 (IL-27) is a new IL-12-related heterodimeric cytokine comprising a novel p28 molecule and the Epstein-Barr-virus-induced gene 3 (EBI3) molecules. It augments initiation of T helper type 1-mediated immunity by enhancing the proliferation and cytokine production of T cells. In this study, we examined whether a secreted form of IL-27 subunits would inhibit IL-27-mediated immunological responses. COS-7 cells transduced with the mouse (m) p28 gene secreted a monomeric mp28 protein; however, those transduced with the mEBI3 gene did not detect a mEBI3 protein in the culture supernatants. The secreted mp28 prevented the IL-27-mediated signal transduction and activator of transcription 1 phosphorylation and subsequently inhibited the IL-27-mediated intercellular adhesion molecule-1 induction and interferon-gamma production in CD4(+) T cells. We generated mp28-expressing murine carcinoma Colon 26 cells and inoculated a mixture of the mp28- and mIL-27-expressing Colon 26 cells into syngeneic BALB/c mice. Simultaneous production of mp28 and mIL-27 from Colon 26 cells suppressed IL-27-mediated anti-tumour effects in the mice. We examined the p28-mediated immune suppression by inoculating mp28-expressing myoblasts into allogeneic mice. Forced production of mp28 suppressed the allogeneic cytotoxic T-lymphocyte induction and subsequently retarded the graft rejection. Furthermore, production of both mp28 and mp40, which inhibits the functions of IL-12 and IL-23, prolonged the graft survival longer than the grafts expressing either mp28 or mp40. We propose that p28 can be a regulatory subunit for IL-27-mediated cellular immune responses and a possible therapeutic agent to suppress unfavourable immune responses.

TSU68 prevents liver metastasis of colon cancer xenografts by modulating the premetastatic niche

The aim of this study was to investigate the inhibitory effect of TSU68 [(Z)-5-[(1,2-dihydro-2-oxo-3H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-propanoic acid; SU6668], an inhibitor of vascular endothelial growth factor receptor 2, platelet-derived growth factor receptor beta, and fibroblast growth factor receptor 1 (FGFR1), on colon cancer liver metastasis, and to test the hypothesis that TSU68 modulates the microenvironment in the liver before the formation of metastasis. First, we implanted the highly metastatic human colon cancer TK-4 orthotopically into the cecal walls of nude mice, followed by twice-daily administration of TSU68 (400 mg/kg/d) or vehicle. Five weeks of treatment with TSU68 significantly inhibited liver metastasis compared with the control group (P<0.001). Next, we analyzed the gene expression profile in premetastatic liver using microarrays. Microarray and quantitative reverse transcription-PCR analysis showed that mRNA levels for the chemokine CXCL1 were significantly increased in tumor-bearing mice compared with non-tumor-bearing mice. Moreover, CXCL1 expression was significantly decreased by TSU68 treatment. CXCR2 expression was detected predominantly on tumor cells in orthotopic tumors compared with ectopic tumors. The number of migrating neutrophils in premetastatic liver was significantly decreased in the TSU68-treated group (P<0.001). The amount of interleukin-12 (IL-12) p40 in the portal vein was significantly decreased by TSU68 (P=0.02). Blockade of both CXCR2 and IL-12 p40 with a neutralizing antibody significantly inhibited liver metastasis. These results suggest that the CXCL1/CXCR2 axis is important in cancer metastasis and that TSU68 may modulate the premetastatic niche in the target organ through suppression of the inflammatory response, which might be an alternative mechanism used by antiangiogenic agents.