Novel bispecific nanobody mitigates experimental intestinal inflammation in mice by targeting TNF-α and IL-23p19 bioactivities

BACKGROUND

Inflammatory bowel diseases (IBDs) pose significant challenges in terms of treatment non-response, necessitating the development of novel therapeutic approaches. Although biological medicines that target TNF-α (tumour necrosis factor-α) have shown clinical success in some IBD patients, a substantial proportion still fails to respond.

METHODS

We designed bispecific nanobodies (BsNbs) with the ability to simultaneously target human macrophage-expressed membrane TNF-α (hmTNF-α) and IL-23. Additionally, we fused the constant region of human IgG1 Fc (hIgG1 Fc) to BsNb to create BsNb-Fc.  Our study encompassed in vitro and in vivo characterization of BsNb and BsNb-Fc.

RESULTS

BsNb-Fc exhibited an improved serum half-life, targeting capability and effector function than BsNb. It's demonstrated that BsNb-Fc exhibited superior anti-inflammatory effects compared to the anti-TNF-α mAb (infliximab, IFX) combined with anti-IL-12/IL-23p40 mAb (ustekinumab, UST) by Transwell co-culture assays. Notably, in murine models of acute colitis brought on by 2,4,6-trinitrobenzene sulfonic acid（TNBS) and dextran sulphate sodium (DSS), BsNb-Fc effectively alleviated colitis severity. Additionally, BsNb-Fc outperformed the IFX&UST combination in TNBS-induced colitis, significantly reducing colon inflammation in mice with colitis produced by TNBS and DSS.

CONCLUSION

These findings highlight an enhanced efficacy and improved biostability of BsNb-Fc, suggesting its potential as a promising therapeutic option for IBD patients with insufficient response to TNF-α inhibition.

KEY POINTS

A bispecific nanobody (BsNb) was created to target TNF-α and IL-23p19, exhibiting high affinity and remarkable stability. BsNb-Fc inhibited the release of cytokines in CD4+T cells during co-culture experiments. BsNb-Fc effectively alleviated colitis severity in mouse model with acute colitis induced by DSS or TNBS, outperforming the IFX&UST combination.

Generation and Characterization of Mirikizumab, a Humanized Monoclonal Antibody Targeting the p19 Subunit of IL-23

Interleukin (IL)-23 exists as a heterodimer consisting of p19 and p40 and is a key cytokine for promoting inflammatory responses in a variety of target organs. IL-23 plays a key role in the differentiation and maintenance of T helper 17 cells, and deregulation of IL-23 can result in autoimmune pathologies of the skin, lungs, and gut. This study describes the generation and characterization of mirikizumab (miri), a humanized IgG4 monoclonal antibody directed against the p19 subunit of IL-23. Miri binds human and cynomolgus monkey IL-23 with high affinity and binds rabbit IL-23 weakly but does not bind to rodent IL-23 or the other IL-23 family members IL-12, IL-27, or IL-35. Miri effectively inhibits the interaction of IL-23 with its receptor, and potently blocks IL-23-induced IL-17 production in cell-based assays while preserving the function of IL-12. In both local and systemic in vivo mouse models, miri blocked IL-23-induced keratin mRNA or IL-17 production, respectively. These data provide a comprehensive preclinical characterization of miri, for which efficacy and safety have been demonstrated in human clinical trials for psoriasis, ulcerative colitis, and Crohn's disease. SIGNIFICANCE STATEMENT: This article describes the generation and characterization of mirikizumab, a high affinity, neutralizing IgG4 variant monoclonal antibody that is under development for the treatment of ulcerative colitis and Crohn's disease. Neutralization of interleukin (IL)-23 is achieved by preventing the binding of IL-23 p19 subunit to the IL-23 receptor and does not affect the IL-12 pathway.

Targeting IL-23 for the interception of obesity-associated colorectal cancer

Inflammation and obesity are two major factors that promote Colorectal cancer (CRC). Our recent data suggests that interleukin (IL)-23, is significantly elevated in CRC tumors and correlates with patient obesity, tumor grade and survival. Thus, we hypothesize that obesity and CRC may be linked via inflammation and IL-23 may be a potential target for intervention in high-risk patients. TCGA dataset and patient sera were evaluated for IL-23A levels. IL-23A [IL-23 p19-/-] knockout (KO) mice were crossed to Apcmin/+ mice and progeny were fed low-fat or high-fat diets. At termination intestines were evaluated for tumorigenesis. Tumors, serum, and fecal contents were analyzed for protein biomarkers, cytokines, and microbiome profile respectively. IL-23A levels are elevated in the sera of patients with obesity and colon tumors. Genetic ablation of IL-23A significantly suppressed colonic tumor multiplicity (76-96 %) and incidence (72-95 %) in male and female mice. Similarly, small-intestinal tumor multiplicity and size were also significantly reduced in IL-23A KO mice. IL-23A knockdown in Apcmin/+ mice fed high-fat diet, also resulted in significant suppression of colonic (50-58 %) and SI (41-48 %) tumor multiplicity. Cytokine profiling showed reduction in several circulating pro-inflammatory cytokines including loss of IL-23A. Biomarker analysis suggested reduced tumor cell proliferation and immune modulation with an increase in tumor-infiltrating CD4+ and CD8+ T-lymphocytes in the IL-23A KO mice compared to controls. Fecal microbiome analysis revealed potentially beneficial changes in the bacterial population profile. In summary, our data indicates a tumor promoting role for IL-23 in CRC including diet-induced obesity. With several IL-23 targeted therapies in clinical trials, there is a great potential for targeting this cytokine for CRC prevention and therapy.

Efficacy and Safety of IL-12/23 and IL-23 Inhibitors for Crohn's Disease: Systematic Review and Meta-Analysis

BACKGROUND

Targeting interleukin-23 (IL-23) is an important therapeutic strategy for Crohn's disease (CD).

AIMS

This systematic review and meta-analysis assessed the efficacy and safety of selective IL-23p19 and IL-12/23p40 inhibitors in patients with moderate-to-severe CD.

METHODS

MEDLINE, Embase, and the Cochrane library (CENTRAL) were searched from inception to May 24, 2023, for randomized, placebo- or active comparator-controlled induction and/or maintenance trials of selective IL-23p19 and IL-12/23p40 inhibitors in pediatric and adult patients with CD. The primary outcome was the proportion of patients in clinical remission. Secondary outcomes were clinical response, endoscopic remission, endoscopic response, and safety. Data were pooled using a random-effects model. Risk of bias and certainty of evidence were assessed using the Cochrane risk of bias tool and the GRADE criteria, respectively.

RESULTS

Eighteen trials (n = 5561) were included. Most studies were rated as low risk of bias. Targeting IL-23 was significantly superior to placebo for inducing clinical (risk ratio [RR] = 1.87, 95% confidence interval [CI] 1.58-2.21) and endoscopic (RR = 3.20, 95%CI 2.17-4.70) remission and maintaining clinical remission (RR = 1.39, 95%CI 1.10-1.77) (GRADE high certainty evidence for all outcomes). Subgroup analysis showed that targeting IL-23 was superior to placebo for inducing clinical remission in biologic-naïve (RR = 2.20, 95%CI 1.46-3.32, I2 = 0%, p = 0.39) and biologic-experienced patients (RR = 1.82, 95%CI 1.27-2.60, I2 = 56.5%, p = 0.01). Targeting IL-23 was associated with a decreased risk of serious adverse events in induction (RR = 0.55, 95%CI 0.44-0.73) and maintenance (RR = 0.72, 95%CI 0.53-0.98) trials compared to placebo (high certainty evidence).

CONCLUSION

Targeting IL-23 is effective and safe for inducing and maintaining clinical and endoscopic remission in patients with moderate-to-severe CD.

Safety of IL-23 p19 Inhibitors for the Treatment of Patients With Moderate-to-Severe Plaque Psoriasis: A Narrative Review

The approved biologics targeting interleukin (IL)-23 p19 for the treatment of moderate-to-severe plaque psoriasis, including guselkumab, tildrakizumab, and risankizumab, have generally favorable safety profiles. The aim of the current review is to describe in detail the safety of these selective inhibitors. A literature search was performed using PubMed from inception to 1 November 2022, to identify clinical trials and real-world evidence publications using the keywords "guselkumab," "tildrakizumab," and "risankizumab." Overall, the most common adverse events (AEs) associated with IL-23 p19 inhibitors in clinical trials were nasopharyngitis, headache, and upper respiratory tract infections. Rates of serious AEs and AEs of interest, including serious infections, nonmelanoma skin cancer (NMSC), malignancies excluding NMSC, major adverse cardiovascular events, and serious hypersensitivity reactions, were not increased with long-term use in clinical trials. Selectively targeting IL-23 p19 was also not associated with elevated risk of opportunistic infections, tuberculosis reactivation, oral candidiasis, or inflammatory bowel disease. Results from real-world studies were similar, supporting the safe long-term use of these biologics in a wider population of patients with psoriasis, including older patients, patients for whom multiple biologics failed, and those with comorbidities such as obesity, metabolic syndrome, cardiovascular disease, dyslipidemia, diabetes, hypertension, and psoriatic arthritis. This review is limited by the lack of direct comparisons among therapeutic agents due to differences among study designs and safety data reporting methods. In conclusion, the favorable safety profiles of IL-23 p19 inhibitors support their long-term use in the management of patients with moderate-to-severe psoriasis.

Safety and pharmacokinetics of IBI112, an IL-23 monoclonal antibody, in Chinese healthy volunteers: a first-in-human phase 1 study

BACKGROUND

Interleukin (IL) 23p19 monoclonal antibodies were efficacious and safe in the treatment of psoriasis. A first-in-human (FIH) study was conducted to evaluate the safety, tolerability, pharmacokinetics (PK) and immunogenicity of IBI112, a novel IL-23p19 monoclonal antibody.

METHODS

In this FIH, randomized, double-blind, placebo-controlled, single-ascending-dose study, a subcutaneous (SC, 5-600 mg) or intravenous (IV, 100 and 600 mg) or placebo was administered to eligible healthy subjects. Safety was assessed by physical examinations, vital signs, laboratory tests, and electrocardiograms. Furthermore, non-compartment analysis and population PK modeling were conducted to characterize PK, and model-based simulation was applied to justify dose selection for psoriasis patients.

RESULTS

A total of 46 subjects were enrolled, with 35 receiving IBI112 and 11 receiving placebo. No serious adverse events (SAEs) and no clinically significant adverse events were identified. After a single SC of IBI112, the median Tmax was 4-10.5 days, and the half-life (t1/2) ranged from 21.8 to 35.8 days. IBI112 exposures (Cmax and AUCinf) approached dose proportionality across 5-300 mg range.

CONCLUSION

IBI112 was well tolerated and safe at SC or IV dose up to 600 mg and showed a linear PK characteristics at SC dose from 5 to 300 mg.

CLINICAL TRIAL REGISTRATION

ClinicalTrial.gov NCT04511624.

CD4+ and CD25+ T-cell response to short-time interferon-beta therapy on IL10, IL23A and FOXP3 genes in multiple sclerosis patients

AIM OF THE STUDY

Interferon-beta (IFN-β), multiple sclerosis (MS) drug for years, does not have therapeutic effects on each patient. Yet, a considerable portion has experienced no therapeutic response to IFN-β. Therefore, it is necessary to determine disease-specific biomarkers that affect drug response. Here, we aimed to determine the effects of interleukin 10 (IL10) and 23 (IL23A), as well as forkhead box P3 (FOXP3) genes on MS after IFN-β therapy.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMCs) of 42 MS patients were isolated to obtain CD4+ and CD25+ T cells. Both cell types were characterised by flow cytometry. To determine optimum drug concentration of IFN-β, cytotoxicity assays were assessed on each cell type for 4, 16, 24 and 48 hours respectively. Then, cells were cultured in the presence of 500 IU/mL of IFN-β. cDNA synthesis was performed after mRNA extraction. RT-PCR was performed to measure gene expressions of IL10, IL23A and FOXP3. Results were evaluated statistically.

RESULTS

It was found that the cytotoxic effect of IFN-β was more efficient as the exposure time was expanded regardless of drug concentration. Moreover, CD25+ T lymphocytes were more resistant to IFN-β. IL23A was down-regulated, whereas FOXP3 was up-regulated at 48 hours in CD4+ T cells. For CD25+ T cells, the graded increase in FOXP3 was obtained while IL10 expression was gradually decreased throughout the drug intake.

CONCLUSION

Although a considerable change in expression was obtained, the long-term IFN-β effect on both genes and cells should be determined by follow-up at least a year.

Gene expression profiling of giant fibroadenomas of the breast

INTRODUCTION

Fibroadenomas of the breast present as two phenotypic variants. The usual variety is 5 cm or less in diameter and there is another large variant called giant fibroadenoma which is greater than 5 cm in diameter. Despite of its large size, it is not malignant. The aim of our study is to determine whether this large variant is different from the usual fibroadenoma in terms of its biological pathways and biomarkers.

METHODS

mRNA was extracted from 44 fibroadenomas and 36 giant fibroadenomas, and transcriptomic profiling was performed to identify up- and down-regulated genes in the giant fibroadenomas as compared to the fibroadenomas.

RESULTS

A total of 40 genes were significantly up-regulated and 18 genes were significantly down-regulated in the giant fibroadenomas as compared to the fibroadenomas of the breast. The top 5 up-regulated genes were FN1, IL3, CDC6, FGF8 and BMP8A. The top 5 down-regulated genes were TNR, CDKN2A, COL5A1, THBS4 and BMPR1B. The differentially expressed genes (DEGs) were found to be associated with 5 major canonical pathways involved in cell growth (PI3K-AKT, cell cycle regulation, WNT, and RAS signalling) and immune response (JAK-STAT signalling). Further analyses using 3 supervised learning algorithms identified an 8-gene signature (FN1, CDC6, IL23A, CCNA1, MCM4, FLT1, FGF22 and COL5A1) that could distinguish giant fibroadenomas from fibroadenomas with high predictive accuracy.

CONCLUSION

Our findings demonstrated that the giant fibroadenomas are biologically distinct to fibroadenomas of the breast with overexpression of genes involved in the regulation of cell growth and immune response.

Levels of the interleukins 17A, 22, and 23 and the S100 protein family in the gingival crevicular fluid of psoriatic patients with or without periodontitis

BACKGROUND

Psoriasis and periodontitis are immunologically mediated chronic inflammatory diseases. Epidemiologic evidence has linked both; however, the change of markers in gingival crevicular fluid has been poorly evaluated.

OBJECTIVE

To evaluate the levels of IL-17A, IL-22, IL-23, S100A7, S100A8, and S100A9 in gingival crevicular fluid of psoriatic and healthy subjects with and without periodontitis and their relations to psoriasis severity.

METHODS

Cross-sectional study. Sample comprised the following groups: healthy controls without periodontitis or with mild periodontitis (n=21), healthy controls with moderate or severe periodontitis (n=18), individuals with psoriasis without or mild periodontitis (n=11), and individuals with psoriasis and moderate or severe periodontitis (n=32). Levels of IL-17A, IL-22, IL-23, S100A8, and S100A9 were determined by multiplex assay and S100A7 was measured by ELISA.

RESULTS

No inter-group differences in the levels of IL-17A, IL-22, IL-23, and S100A7 were found. S100A8 levels were higher in psoriatic patients than controls (p<0.05). S100A8 was positively correlated with psoriasis severity in the group with psoriasis (p<0.05). S100A9 exceeded the detection limits.

STUDY LIMITATIONS

This pilot study presents a small sample size.

CONCLUSIONS

The concentrations of S100A8 were highest in psoriatic patients regardless of periodontal health/status. S100A8 was associated with the severity of psoriasis. The concentrations of interleukins and S100A7 were similar in psoriatic patients with or without periodontitis vs. healthy controls.

Periodontal Conditions and Whole Salivary IL-17A and -23 Levels among Young Adult Cannabis sativa (Marijuana)-Smokers, Heavy Cigarette-Smokers and Non-Smokers

In the United States, prevalence of marijuana-use has doubled in the past 2 decades. The aim was to compare the periodontal conditions and whole-salivary IL-17A and IL-23 levels among young adult marijuana-smokers, heavy cigarette-smokers and non-smokers. Self-reported marijuana-smokers, heavy-cigarette-smokers, non-smokers with periodontitis and periodontally-healthy non-smokers were included. Demographic data was recorded and full-mouth plaque index (PI), bleeding on probing (BoP), probing depth (PD) and clinical attachment loss (AL), marginal bone loss (MBL) and missing teeth were recorded. Levels of IL-17A and IL-23 levels were measured in the whole saliva. p < 0.01 was considered statistically significant. Fifteen-marijuana-smokers, 15 heavy-cigarette-smokers, 16 non-smokers-with-periodontitis and 15 periodontally-healthy-non-smokers) were included. The clinicoradiographic parameters were worse among marijuana-smokers (p < 0.01), cigarette-smokers (p < 0.01) and non-smokers-with-periodontitis (p < 0.01) than periodontally-healthy-non-smokers. Marijuana- and cigarette-smokers had Stage-IV/Grade C and non-smokers with periodontitis had Stage-III/Grade-C. Salivary IL-17A and IL-23 levels were higher in marijuana-smokers than cigarette-smokers (p < 0.01) and non-smokers-with-periodontitis (p < 0.01). Whole salivary IL-17A and IL-23 levels were higher among cigarette-smokers than non-smokers with periodontitis (p < 0.01) and periodontally-healthy-individuals (p < 0.01). Marijuana- and heavy cigarette-smokers have comparable clinicoradiographic periodontal statuses. This rejects hypothesis-1. However, whole salivary immunoinflammatory response may be moderately worse in marijuana-smokers compared with heavy cigarette-smokers and non-smoker with periodontitis thereby supporting hypothesis-2.

Efficacy and safety of guselkumab in patients with active psoriatic arthritis: a randomised, double-blind, placebo-controlled, phase 2 study

BACKGROUND

Guselkumab, a human monoclonal antibody that binds to the p19 subunit of interleukin 23, has been approved for the treatment of moderate-to-severe psoriasis. Psoriatic arthritis is a common comorbidity of psoriasis with an umet need for novel treatments. We assessed the efficacy and safety of guselkumab in patients with active psoriatic arthritis.

METHODS

We did a randomised, double-blind, placebo-controlled, phase 2a trial at 34 rheumatology and dermatology practices in Canada, Germany, Poland, Romania, Russia, Spain, and the USA. Eligible participants were aged 18 years or older with active psoriatic arthritis and plaque psoriasis affecting at least 3% of their body surface area, with three or more of 66 tender joints and three or more of 68 swollen joints, who had an inadequate response or intolerance to standard treatments. We randomly assigned patients (2:1) via a central interactive web-response system using computer-generated permuted blocks with a block size of six, stratified by previous anti-tumour necrosis factor-α use, to receive subcutaneous guselkumab 100 mg or placebo at week 0, week 4, and every 8 weeks thereafter for 24 weeks. Patients, investigators, and site staff were masked to treatment assignment until final database lock at week 56. At week 16, patients with less than 5% improvement in swollen and tender joint counts were eligible for early escape to ustekinumab. At week 24, the remaining placebo-treated patients crossed over to receive guselkumab 100 mg at weeks 24, 28, 36, and 44 and guselkumab-treated patients received a placebo injection at week 24, followed by guselkumab injections at weeks 28, 36, and 44. The primary endpoint was the proportion of patients with at least 20% improvement at week 24 in signs and symptoms of psoriatic arthritis according to American College of Rheumatology criteria (ACR20) in the modified intention-to-treat population (ie, all randomly assigned patients who received at least one dose of study treatment). Safety analyses included patients according to the study drug received. This study is registered with ClinicalTrials.gov, number NCT02319759.

FINDINGS

Between March 27, 2015, and Jan 17, 2017, we randomly assigned 149 patients to treatment: 100 to guselkumab and 49 to placebo. 17 (35%) of 49 patients in the placebo group and ten (10%) of 100 patients in the guselkumab group were eligible for early escape to ustekinumab at week 16. 29 (59%) of 49 patients in the placebo group crossed over and received guselkumab at week 24. Three (6%) of 49 patients in the placebo group, one (3%) of 29 patients who crossed over from placebo to guselkumab, and six (6%) of 100 patients in the guselkumab group discontinued study treatment before week 44. 58 (58%) of 100 patients in the guselkumab group and nine (18%) of 49 patients in the placebo group achieved an ACR20 response at week 24 (percentage difference 39·7% [95% CI 25·3-54·1]; p<0·0001). Between week 0 and week 24, 36 (36%) of 100 guselkumab-treated patients and 16 (33%) of 49 placebo-treated patients had at least one adverse event. The most frequent adverse event was infection in both groups (16 [16%] of 100 patients in the guselkumab group vs ten [20%] of 49 patients in the placebo group). The prevalence of adverse events between week 0 and week 56 in guselkumab-treated patients (51 [40%] of 129) indicated no disproportional increase with longer guselkumab exposure. No deaths occurred.

INTERPRETATION

Guselkumab, a novel anti-interleukin 23p19 antibody, significantly improved signs and symptoms of active psoriatic arthritis and was well tolerated during 44 weeks of treatment. The results of this study support further development of guselkumab as a novel and comprehensive treatment in psoriatic arthritis.

FUNDING

Janssen Research & Development.

[Interleukin-23 strengthens the anti-apoptotic and drug resistance of human tongue squamous cell carcinoma through the Wingless-related integration site/β-catenin pathway]

OBJECTIVE

This study aims to detect the expression level of interleukin-23 (IL-23) in tongue squamous cell carcinoma tissues and its relationship with clinical prognosis, as well as explore the anti-apoptotic and drug resistance of the tongue squamous cell line-SCC9 before and after treatment with IL-23.

METHODS

The expression of IL-23 in tumor tissues from 28 tongue cancer patients was analyzed by immunohistochemistry assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression of Wingless-related integration site (Wnt)1 and c-myc in SCC9 cells treated with different IL-23 concentrations. After interferencing the β-catenin with small interfering RNA (siRNA), the expression of β-catenin, B-cell lymphoma-2 (Bcl-2), ATP-binding cassette sub-family G member 2 (ABCG2), and permeability-glycoprotein (P-gp) in SCC9 was measured by Western blot analysis. The effect of IL-23 on the apoptotic resistance of SCC9 to cisplatin was examined by methyl thiazolyl tetrazolium test.

RESULTS

The expression of IL-23 in tongue cancer tissues was correlated with lymphatic metastasis, nerve invasion, and the recurrence after therapy (P<0.05). After dealing with IL-23, SCC9 showed the upregulation effect of Bcl-2, ABCG2 and P-gp expressions. IL-23 was closely related to the activation level of the Wnt pathway and significantly strengthened the resistance to cisplatin (P<0.01).

CONCLUSION

IL-23 activates the Wnt pathway in tongue squamous cell carcinoma, thereby enhancing its resistance to apoptosis and drug.

Absence of IL-23p19 in donor allogeneic cells reduces mortality from acute GVHD

The p19 dimer of interleukin 23 (IL-23) has been reported to have a major role in the pathogenesis of many experimental and clinical autoimmune diseases and may also have a prominent role in transplantation. We reasoned that deficiency of p19 in the allogeneic donor transplant might reduce the inflammation caused by acute GVHD (aGVHD). The major histocompatibility complex-2 (H2(d)) BALB/c mice were subjected to 8.5 Gy TBI, followed by transplantation with 10 x 10(6) BM and 2.5 x 10(6) spleen cells from H2(d) BALB/c, H2(b) C57Bl/6 (B6) or H2(b) p19-/- donors. In all, 75% of the p19-/- transplanted mice survived, compared with only 12.5% of the B6 transplanted mice. This superior survival is correlated with significantly less severe aGVHD, absence of p19 after transplantation, less upregulation of mRNA and lower serum levels of IL-17 as compared with the B6 transplants. TBI alone significantly upregulated transforming growth factor-beta (TGF-beta), IL-6 and p19 mRNA levels in host BALB/c mice, possibly providing the milieu to induce IL-17 in p19-/- donor cells. IL-22, another cytokine, the induction of which in T-helper 17 (Th17) cells is supported by p19, was upregulated in BALB/c hosts but not in transplanted B6 or p19 donor cells, and may not have had a major role in modifying aGVHD.

Immune enhancement and anti-tumour activity of IL-23

Immunotherapy, including the use of cytokines and/or modified tumour cells immune stimulatory cytokines, can enhance the host anti-tumour immune responses. Interleukin-23 (IL-23) is a relative novel cytokine, which consists of a heterodimer of the IL-12p40 subunit and a novel p19 subunit. IL-23 has biological activities similar to but distinct from IL-12. IL-23 can enhance the proliferation of memory T cells and the production of IFN-gamma, IL-12 and TNF-alpha from activated T cells. IL-23 activates macrophages to produce TNF-alpha and nitric oxide. IL-23 can also act directly on dendritic cells and possesses potent anti-tumour and anti-metastatic activity in murine models of cancer. IL-23 can also induce a lower level of IFN-gamma production compared with that induced by IL-12. This may make IL-23 an alternative and safer therapeutic agent for cancer, as IL-12 administration can lead to severe toxic side effects because of the extremely high levels of IFN-gamma it induces.

IL-17 production is dominated by gammadelta T cells rather than CD4 T cells during Mycobacterium tuberculosis infection

IL-17 is a cytokine produced by T cells in response to IL-23. Recent data support a new subset of CD4 Th cells distinct from Th1 or Th2 cells that produce IL-17 and may contribute to inflammation. In this study, we demonstrate that, in naive mice, as well as during Mycobacterium tuberculosis infection, IL-17 production is primarily from gammadelta T cells and other non-CD4(+)CD8(+) cells, rather than CD4 T cells. The production of IL-17 by these cells is stimulated by IL-23 alone, and strongly induced by the cytokines, including IL-23, produced by M. tuberculosis-infected dendritic cells. IL-23 is present in the lungs early in infection and the IL-17-producing cells, such as gammadelta T cells, may represent a central innate protective response to pulmonary infection.

Serum amyloid A is an endogenous ligand that differentially induces IL-12 and IL-23

The acute-phase proteins, C-reactive protein and serum amyloid A (SAA), are biomarkers of infection and inflammation. However, their precise role in immunity and inflammation remains undefined. We report in this study a novel property of SAA in the differential induction of Th1-type immunomodulatory cytokines IL-12 and IL-23. In peripheral blood monocytes and the THP-1 monocytic cell line, SAA induces the expression of IL-12p40, a subunit shared by IL-12 and IL-23. SAA-stimulated expression of IL-12p40 was rapid (< or = 4 h), sustainable (> or = 20 h), potent (up to 3380 pg/ml/10(6) cells in 24 h), and insensitive to polymyxin B treatment. The SAA-stimulated IL-12p40 secretion required de novo protein synthesis and was accompanied by activation of the transcription factors NF-kappaB and C/EBP. Expression of IL-12p40 required activation of the p38 MAPK and PI3K. Interestingly, the SAA-induced IL-12p40 production was accompanied by a sustained expression of IL-23p19, but not IL-12p35, resulting in preferential secretion of IL-23, but not IL-12. These results identify SAA as an endogenous ligand that potentially activates the IL-23/IL-17 pathway and present a novel mechanism for regulation of inflammation and immunity by an acute-phase protein.

Acute alcohol intoxication suppresses the interleukin 23 response to Klebsiella pneumoniae infection

BACKGROUND

Bacterial pneumonia is a widely recognized infection in the alcohol-abusing patient. Interleukin 23 (IL-23) is a recently described cytokine critical for IL-17 induction and host survival during Klebsiella pneumoniae infection, a pulmonary pathogen commonly seen in alcoholics. We investigated the effect of acute alcohol intoxication on the IL-23 response to this infection.

METHODS

Male C57BL/6 mice were given an intraperitoneal injection of ethanol (3.0 g/kg) or phosphate-buffered saline (PBS) 30 minutes before infection. Alveolar macrophages (AM) were cultured with bacteria in ethanol (0, 50, and 100 mM) to determine alcohol's effect on AM IL-23 expression, the bioactivity of which was determined by splenocyte IL-17 inducing activity. The role of IL-10 in alcohol-mediated suppression of AM IL-23 p19 mRNA expression was assessed using wild-type (WT) and IL-10 knock-out (KO) mice. Efficacy of AM pretreatment with interferon gamma (IFN-gamma) on IL-23 expression before ethanol exposure and infection was evaluated.

RESULTS

In vivo, acute intoxication suppresses the lung and bronchoalveolar lavage cell IL-23 response to pathogen. This effect was confirmed in vitro as ethanol dose-dependently inhibits AM IL-23 during infection. Acute intoxication increases lung and BAL cell IL-10 mRNA expression 2 hours after in vivo infection and, in vitro, recombinant IL-10 inhibits AM IL-23 expression. However, alcohol impairs IL-23 similarly in AM harvested from both WT and IL-10 KO mice. Interferon gamma pretreatment strongly inhibits AM IL-23 production in both the presence and absence of alcohol.

CONCLUSIONS

Acute alcohol intoxication inhibits the pulmonary IL-23 response to K. pneumoniae infection both in vivo and in vitro, an effect independent of IL-10 induction. Interferon gamma priming antagonizes IL-23 and is, therefore, not likely to be a useful adjuvant therapy in restoring IL-23/IL-17 responses during infection and intoxication.

Cutting edge: IL-23 cross-regulates IL-12 production in T cell-dependent experimental colitis

Although IL-12 and IL-23 share the common p40 subunit, IL-23, rather than IL-12, seems to drive the pathogenesis of experimental autoimmune encephalomyelitis and arthritis, because IL-23/p19 knockout mice are protected from disease. In contrast, we describe in this study that newly created LacZ knockin mice deficient for IL-23 p19 were highly susceptible for the development of experimental T cell-mediated TNBS colitis and showed even more severe colitis than wild-type mice by endoscopic and histologic criteria. Subsequent studies revealed that dendritic cells from p19-deficient mice produce elevated levels of IL-12, and that IL-23 down-regulates IL-12 expression upon TLR ligation. Finally, in vivo blockade of IL-12 p40 in IL-23-deficient mice rescued mice from lethal colitis. Taken together, our data identify cross-regulation of IL-12 expression by IL-23 as novel key regulatory pathway during initiation of T cell dependent colitis.

IL-17A-producing neutrophil-regulatory Tn lymphocytes

The proinflammatory cytokine IL-17A, mainly produced by specialized T cells, plays an important homeostatic role in regulating neutrophil production and blood neutrophil counts. This review will assemble and discuss the evidence for this function of IL-17A-producing cells, which are collectively called neutrophil-regulatory T cells or Tn cells. IL-17A-producing lymphocytes are most abundant in the mesenteric lymph node, where they account for 0.15% of all lymphocytes. About 60% of the Tn cells are gammadelta T cells, about 25% NKTlike cells, and less than 15% are CD4 T cells. These latter cells are also known as T-17 or ThIL-17 cells, a subset of Tn cells that also plays an important role in autoimmune diseases. IL-17A produced by Tn cells regulates the production of G-CSF, which in turn promotes the proliferation of promyelocytes and maturation of neutrophils. This homeostatic mechanism plays an important role in normal physiology and in host defense against bacterial infections. This review is aimed at highlighting the important role of IL-17A-producing T cells at the interface between the adaptive and innate immune system.

An Anti-IL-12p40 Antibody Down-Regulates Type 1 Cytokines, Chemokines, and IL-12/IL-23 in Psoriasis

Psoriasis is characterized by activation of T cells with a type 1 cytokine profile. IL-12 and IL-23 produced by APCs are essential for inducing Th1 effector cells. Promising clinical results of administration of an Ab specific for the p40 subunit of IL-12 and IL-23 (anti-IL-12p40) have been reported recently. This study evaluated histological changes and mRNA expression of relevant cytokines and chemokines in psoriatic skin lesions following a single administration of anti-IL-12p40, using immunohistochemistry and real-time RT-PCR. Expression levels of type 1 cytokine (IFN-gamma) and chemokines (IL-8, IFN-gamma-inducible protein-10, and MCP-1) were significantly reduced at 2 wk posttreatment. The rapid decrease of these expression levels preceded clinical response and histologic changes. Interestingly, the level of an anti-inflammatory cytokine, IL-10, was also significantly reduced. Significant reductions in TNF-alpha levels and infiltrating T cells were observed in high responders (improvement in clinical score, > or =75% at 16 wk), but not in low responders. Of importance, the levels of APC cytokines, IL-12p40 and IL-23p19, were significantly decreased in both responder populations, with larger decreases in high responders. In addition, baseline levels of TNF-alpha significantly correlated with the clinical improvement at 16 wk, suggesting that these levels may predict therapeutic responsiveness to anti-IL-12p40. Thus, in a human Th1-mediated disease, blockade of APC cytokines by anti-IL-12p40 down-regulates expression of type 1 cytokines and chemokines that are downstream of IL-12/IL-23, and also IL-12/IL-23 themselves, with a pattern indicative of coordinated deactivation of APCs and Th1 cells.

Rac1 Negatively Regulates Lipopolysaccharide-Induced IL-23 p19 Expression in Human Macrophages and Dendritic Cells and NF-κB p65 trans Activation Plays a Novel Role

IL-23 is a heterodimeric cytokine composed of a unique p19 subunit and of a p40 subunit that is also common to IL-12. We defined the distinct signaling mechanisms that regulate the LPS-mediated induction of IL-23 p19 and p40 in human macrophages and dendritic cells. We found that the overexpression of dominant-negative Rac1 (N17Rac1) enhanced LPS-induced IL-23 p19 expression but did not alter p40 expression or IL-12 p70 production in PMA-treated THP-1 macrophages and in human monocyte-derived dendritic cells. Although the inhibition of either p38 MAPK or JNK enhanced LPS-induced p19 expression, N17Rac1 did not influence either p38 MAPK or JNK activation. By contrast, N17Rac1 augmented both NF-kappaB gene expression and p65 trans activation stimulated by LPS without affecting the degradation of IkappaB-alpha or DNA binding to NF-kappaB. Furthermore, small interference RNA of NF-kappaB p65 attenuated cellular amounts of p65 and suppressed LPS-induced p19 expression but did not affect p40 expression. Our findings indicate that Rac1 negatively controls LPS-induced IL-23 p19 expression through an NF-kappaB p65 trans activation-dependent, IkappaB-independent pathway and that NF-kappaB p65 regulates LPS-induced IL-23 p19, but not p40, expression, which causes differences in the control of IL-23 p19 and p40 expression by Rac1.

Visualization of IL-12/23p40 in vivo reveals immunostimulatory dendritic cell migrants that promote Th1 differentiation

IL-12p40 is induced in macrophages and dendritic cells (DC) after activation by microbial TLR ligands and cytokines and constitutes a component of IL-12 and IL-23. In an effort to understand the location and kinetics of these cytokines during the course of an immune response, we generated knockin (gene-targeted) mice that express the p40 gene linked via a viral internal ribosome entry site element with fluorescent reporters, eYFP or eGFP. Macrophages and DC from these mice faithfully reported biallelic p40 induction using the fluorescent marker. s.c. inoculation with Listeria monocytogenes or LPS led to a rapid, but transient, accumulation of p40-expressing DC in draining lymph nodes, which could be blocked by the addition of pertussis toxin. In situ analysis also revealed the accumulation of IL-12p40 protein around high endothelial venules located in close proximity to p40-expressing DC. Consistent with the in vivo findings, in vitro-activated DC that expressed p40 migrated to draining lymph nodes and promoted Th1 differentiation more efficiently than DC that did not express p40. Accordingly, these mice provide a valuable tool for tracking critical functions of DC in vivo and should bestow a useful reagent for exploring the effector biology of these cells in models of infectious disease, cancer immunity, and vaccine development.

Cutting edge: IFN-gamma regulates the induction and expansion of IL-17-producing CD4 T cells during mycobacterial infection

T cell responses are important to the control of infection but are deleterious if not regulated. IFN-gamma-deficient mice infected with mycobacteria exhibit enhanced accumulation of activated effector T cells and neutrophils within granulomatous lesions. These cells do not control bacterial growth and compromise the integrity of the infected tissue. We show that IFN-gamma-deficient mice have increased numbers of IL-17-producing T cells following infection with Mycobacterium bovis bacille Calmette Guérin. Furthermore, exogenous IFN-gamma increases IL-12 and decreases IL-23 production by bacille Calmette Guérin-infected bone marrow-derived dendritic cells and reduces the frequency of IL-17-producing T cells induced by these bone marrow-derived dendritic cells. These data support the hypothesis that, during mycobacterial infection, both IFN-gamma- and IL-17-producing T cells are induced, but that IFN-gamma serves to limit the IL-17-producing T cell population. This counterregulation pathway may be an important factor in limiting mycobacterially associated immune-mediated pathology.

Dendritic cells transduced with SOCS-3 exhibit a tolerogenic/DC2 phenotype that directs type 2 Th cell differentiation in vitro and in vivo

Dendritic cells (DCs) have been suggested to direct a type of Th differentiation through their cytokine profile, e.g., high IL-12/IL-23 for Th1 (named DC1/immunogenic DCs) and IL-10 for Th2 (DC2/tolerogenic DCs). Suppressor of cytokine signaling (SOCS)-3 is a potent inhibitor of Stat3 and Stat4 transduction pathways for IL-23 and IL-12, respectively. We thus hypothesize that an enhanced SOCS-3 expression in DCs may block the autocrine response of IL-12/IL-23 in these cells, causing them to become a DC2-type phenotype that will subsequently promote Th2 polarization of naive T cells. Indeed, in the present study we found that bone marrow-derived DCs transduced with SOCS-3 significantly inhibited IL-12-induced activation of Stat4 and IL-23-induced activation of Stat3. These SOCS-3-transduced DCs expressed a low level of MHC class II and CD86 on their surface, produced a high level of IL-10 but low levels of IL-12 and IFN-gamma, and expressed a low level of IL-23 p19 mRNA. Functionally, SOCS-3-transduced DCs drove naive myelin oligodendrocyte glycoprotein-specific T cells to a strong Th2 differentiation in vitro and in vivo. Injection of SOCS-3-transduced DCs significantly suppressed experimental autoimmune encephalomyelitis, a Th1 cell-mediated autoimmune disorder of the CNS and an animal model of multiple sclerosis. These results indicate that transduction of SOCS-3 in DCs is an effective approach to generating tolerogenic/DC2 cells that then skew immune response toward Th2, thus possessing therapeutic potential in Th1-dominant autoimmune disorders such as multiple sclerosis.

Excess IL-12 but not IL-23 accompanies the inflammatory bowel disease associated with common variable immunodeficiency

BACKGROUND & AIMS

Common variable immunodeficiency (CVID) patients can develop an idiopathic inflammatory bowel disease resulting in chronic diarrhea and life-threatening malabsorption. This study was designed to assess the status of the gastrointestinal tract and to define the mucosal immune abnormalities in patients with and without symptomatic gut inflammatory disease.

METHODS

CVID patients underwent tests of gut absorption, peripheral blood mononuclear cell phenotyping, and upper and lower endoscopy for histology and lamina propria mononuclear cell (LPMC) cytokine production.

RESULTS

CVID patients with gastrointestinal symptoms differed from asymptomatic CVID patients by having significantly longer duration of disease and lower body mass index, D-xylose absorption, serum albumin, CD4/CD45RA cells, CD3/CD25 cells, and natural killer cells. Symptomatic CVID patients showed diffuse histologic inflammatory changes in the duodenal and colonic mucosa including villus blunting, increased lamina propria and intraepithelial lymphocytes, and epithelial apoptosis, less frequently seen in asymptomatic patients. LPMCs from symptomatic CVID patients produced significantly higher T-helper (Th) 1 cytokines, interleukin-12, and interferon-gamma. Compared with the Th1 cytokines produced by LPMCs from Crohn's disease, CVID patients did not produce excess amounts of interleukin-23, interleukin-17, or tumor necrosis factor-alpha.

CONCLUSIONS

The idiopathic inflammatory bowel disease associated with gastrointestinal symptoms in CVID is a unique combination of diverse histologic findings accompanied by excessive Th1 cytokine production, distinct from that in Crohn's disease. These data show that human gut mucosal inflammatory disease can occur with excess interleukin-12 and interferon-gamma production alone and provide a rationale for developing targeted therapies for this complication of CVID.

Responses to Leishmania donovani in mice deficient in interleukin-12 (IL-12), IL-12/IL-23, or IL-18

Interleukin-12 (IL-12) orchestrates acquired resistance in intracellular Leishmania donovani infection in the liver, inducing gamma interferon and, in turn, macrophage activation and parasite killing. Nevertheless, testing in IL-18(-/-) mice compared to wild-type mice and in IL-12p40(-/-) compared to IL-12p35(-/-) mice also suggested both early-acting (IL-18) and late-acting (IL-23) antileishmanial effects independent of IL-12.

Intracellular network of phosphatidylinositol 3-kinase, mammalian target of the rapamycin/70 kDa ribosomal S6 kinase 1, and mitogen-activated protein kinases pathways for regulating mycobacteria-induced IL-23 expression in human macrophages

We previously demonstrated that Mycobacterium tuberculosis (M. tbc)-induced interleukin (IL)-12 expression is negatively regulated by the phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) 1/2 pathways in human monocyte-derived macrophages (MDMs). To extend these studies, we examined the nature of the involvement of toll-like receptors (TLRs) and intracellular signalling pathways downstream from PI3K in M. tbc-induced IL-23 expression in human MDMs. M. tbc-induced Akt activation and IL-23 expression were essentially dependent on TLR2. Blockade of the mammalian targets of rapamycin (mTOR)/70 kDa ribosomal S6 kinase 1 (S6K1) pathway by the specific inhibitor rapamycin greatly enhanced M. tbc-induced IL-12/IL-23 p40 (p40) and IL-23 p19 (p19) mRNA and IL-23 protein expression. In sharp contrast, p38 mitogen-activated protein kinase (MAPK) inhibition abrogated the p40 and p19 mRNA and IL-23 protein expression induced by M. tbc. Furthermore, the inhibition of PI3K-Akt, but not ERK 1/2 pathway, attenuated M. tbc-induced S6K1 phosphorylation, whereas PI3K inhibition enhanced p38 phosphorylation and apoptosis signal-regulating kinase 1 activity during exposure to M. tbc. Although the negative or positive regulation of IL-23 was not reversed by neutralization of IL-10, it was significantly modulated by blocking TLR2. Collectively, these findings provide new insight into the homeostatic mechanism controlling type 1 immune responses during mycobacterial infection involving the intracellular network of PI3K, S6K1, ERK 1/2 and p38 MAPK pathways in a TLR2-dependent manner.

Interleukin-23 and interleukin-27 exert quite different antitumor and vaccine effects on poorly immunogenic melanoma

Recent studies revealed that two novel interleukin (IL)-12-related cytokines, IL-23 and IL-27, have potent antitumor activities. However, the antitumor effects were mainly evaluated in relatively highly immunogenic tumors and have not been fully evaluated against nonimmunogenic or poorly immunogenic tumors. In this study, we investigated the antitumor efficacies of IL-23 and IL-27 on poorly immunogenic B16F10 melanoma and found that the antitumor responses mediated by IL-23 and IL-27 were clearly different. In syngeneic mice, mouse single-chain (sc) IL-23-transfected B16F10 (B16/IL-23) tumors exhibited almost the same growth curve as B16F10 parental tumor about until day 20 after tumor injection and then showed growth inhibition or even regression. In contrast, scIL-27-transfected B16F10 (B16/IL-27) tumors exhibited significant retardation of tumor growth from the early stage. In vivo depletion assay revealed that the antitumor effect of B16/IL-23 was mainly mediated by CD8+ T cells and IFN-gamma whereas that of B16/IL-27 mainly involved natural killer cells and was independent of IFN-gamma. We also found that antitumor effects of B16/IL-23 and B16/IL-27 were synergistically enhanced by treatment with IL-18 and IL-12, respectively. Furthermore, B16/IL-23-vaccinated mice developed protective immunity against parental B16F10 tumors but B16/IL-27-vaccinated mice did not. When combined with prior in vivo depletion of CD25+ T cells, 80% of B16/IL-23-vaccinated mice completely rejected subsequent tumor challenge. Finally, we showed that the systemic administration of neither IL-23 nor IL-27 induced such intense toxicity as IL-12. Our data support that IL-23 and IL-27 might play a role in future cytokine-based immunotherapy against poorly immunogenic tumors.

Differential Activity of IL-12 and IL-23 in Mucosal and Systemic Innate Immune Pathology

The CD40-CD154 pathway is important in the pathogenesis of inflammatory bowel disease. Here we show that injection of an agonistic CD40 mAb to T and B cell-deficient mice was sufficient to induce a pathogenic systemic and intestinal innate inflammatory response that was functionally dependent on tumor necrosis factor-alpha and interferon-gamma as well as interleukin-12 p40 and interleukin-23 p40 secretion. CD40-induced colitis, but not wasting disease or serum proinflammatory cytokine production, depended on interleukin-23 p19 secretion, whereas interleukin-12 p35 secretion controlled wasting disease and serum cytokine production but not mucosal immunopathology. Intestinal inflammation was associated with IL-23 (p19) mRNA-producing intestinal dendritic cells and IL-17A mRNA within the intestine. Our experiments identified IL-23 as an effector cytokine within the innate intestinal immune system. The differential role of IL-23 in local but not systemic inflammation suggests that it may make a more specific target for the treatment of IBD.

T cell infiltration after chronic constriction injury of mouse sciatic nerve is associated with interleukin-17 expression

Interleukin (IL)-17A, a recently described novel T cell cytokine, orchestrates inflammation in a variety of immune-mediated diseases. In the present investigation, we analyzed the temporal gene expression pattern of IL-17A and its main regulators IL-23 and IL-15 after chronic constriction injury (CCI) of the sciatic nerve, a lesion paradigm inducing neuropathic pain, by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in mice. IL-17A displayed a monophasic expression in degenerating nerves at day 7 after CCI while transcripts for the IL-17A regulatory cytokines IL-23 and IL-15 peaked earlier. Accordingly, IL-17A positive T cells were detectable within the endoneurium of the injured nerves by immunocytochemistry. In support of a crucial role of T cell inflammation, RAG-1 knockout mice lacking functional T lymphocytes did not express IL-17A mRNA in distal nerve segments following CCI. Interestingly, T cell deficiency was associated with less thermal hyperalgesia and reduced mRNA levels for the macrophage marker molecule F4/80 and the chemokine macrophage chemoattractant protein-1 (MCP-1) after CCI. Our study supports the notion that T cells and T-cell-derived cytokines contribute to the inflammatory response after peripheral nerve injury.

T-bet negatively regulates autoimmune myocarditis by suppressing local production of interleukin 17

Experimental autoimmune myocarditis (EAM) appears after infectious heart disease, the most common cause of dilated cardiomyopathy in humans. Here we report that mice lacking T-bet, a T-box transcription factor required for T helper (Th)1 cell differentiation and interferon (IFN)-γ production, develop severe autoimmune heart disease compared to T-bet^−/− control mice. Experiments in T-bet^−/−IL-4^−/− and T-bet^−/− IL-4Rα^−/− mice, as well as transfer of heart-specific Th1 and Th2 cell lines, showed that autoimmune heart disease develops independently of Th1 or Th2 polarization. Analysis of T-bet^−/−IL-12Rβ1^−/− and T-bet^−/− IL-12p35^−/− mice then identified interleukin (IL)-23 as critical for EAM pathogenesis. In addition, T-bet^−/− mice showed a marked increase in production of the IL-23–dependent cytokine IL-17 by heart-infiltrating lymphocytes, and in vivo IL-17 depletion markedly reduced EAM severity in T-bet^−/− mice. Heart-infiltrating T-bet^−/− CD8⁺ but not CD8⁻ T cells secrete IFN-γ, which inhibits IL-17 production and protects against severe EAM. In contrast, T-bet^−/− CD8⁺ lymphocytes completely lost their capacity to release IFN-γ within the heart. Collectively, these data show that severe IL-17–mediated EAM can develop in the absence of T-bet, and that T-bet can regulate autoimmunity via the control of nonspecific CD8⁺ T cell bystander functions in the inflamed target organ.

IL-23 is increased in dendritic cells in multiple sclerosis and down-regulation of IL-23 by antisense oligos increases dendritic cell IL-10 production

IL-23 is a heterodimeric cytokine comprising a p19 subunit associated with the IL-12/23p40 subunit. Like IL-12, IL-23 is expressed predominantly by activated dendritic cells (DCs) and phagocytic cells, and both cytokines induce IFN-gamma secretion by T cells. The induction of experimental autoimmune encephalitis, the animal model of multiple sclerosis (MS), occurs in mice lacking IL-12, but not in mice with targeted disruption of IL-23 or both IL-12 and IL-23. Thus, IL-23 expression in DCs may play an important role in the pathogenesis of human autoimmune diseases such as MS. We quantified the expression of IL-23 in monocyte-derived DCs in MS patients and healthy donors and found that DCs from MS patients secrete elevated amounts of IL-23 and express increased levels of IL-23p19 mRNA. Consistent with this abnormality, we found increased IL-17 production by T cells from MS patients. We then transfected monocyte-derived DCs from healthy donors with antisense oligonucleotides specific for the IL-23p19 and IL-12p35 genes and found potent suppression of gene expression and blockade of bioactive IL-23 and IL-12 production without affecting cellular viability or DCs maturation. Inhibition of IL-23 and IL-12 was associated with increased IL-10 and decreased TNF-alpha production. Furthermore, transfected DCs were poor allostimulators in the MLR. Our results demonstrate that an abnormal Th1 bias in DCs from MS patients related to IL-23 exists, and that antisense oligonucleotides specific to IL-23 can be used for immune modulation by targeting DC gene expression.

Optimization, Comparison, and Application of Colorimetric vs. Chemiluminescence Based Indirect Sandwich ELISA for Measurement of Human IL‐23

Currently, there is neither a published ELISA method nor it is clear whether chemiluminescence substrates would provide better sensitivity vs. colorimetric substrates for measuring human IL-23-a recently described Type-1 immunity associated cytokine. Initially, we optimized a colorimetric ELISA using p-nitro-phenyl phosphate substrate. Subsequently, we compared it with chemiluminescence substrates that provided approximately 5-fold enhanced sensitivity (mean sensitivity; 26.3 pg/mL vs. colorimetric assay, 131 pg/mL; p < 0.01). Both methods were reliable, with <10% inter- and intra-assay variations. We then found that the chemiluminescence method was useful in situations where human IL-23 was not readily measurable by a colorimetric method.

New mediators of immunity and inflammation in inflammatory bowel disease

PURPOSE OF REVIEW

In both Crohn's disease and ulcerative colitis, the tissue damage results from an inappropriate or exaggerated immune response to antigens of the gut microflora. This review summarizes current knowledge regarding the role of immune-inflammatory mediators in the pathogenesis of inflammatory bowel disease.

RECENT FINDINGS

Despite having a common basis in overresponsiveness to luminal antigens, Crohn's disease and ulcerative colitis are immunologically distinct entities. Crohn's disease is associated with a Th1 T cell-mediated response, characterized by enhanced production of interferon-gamma and tumor necrosis factor-alpha. Interleukin (IL)-12 and, possibly, IL-23 govern the Th1 cell differentiation, but optimal induction and stabilization of polarized Th1 cells would require additional cytokines, such as IL-15, IL-18 and IL-21. In ulcerative colitis, the local immune response is less polarized, but it is characterized by CD1-reactive natural killer T cell production of IL-13. Beyond these differences, Crohn's disease and ulcerative colitis share important end-stage effector pathways of intestinal injury, which are mediated by an active cross-talk between immune and non-immune mucosal cells.

SUMMARY

The clarification of the complex network of immune-inflammatory mediators operating in the gut of patients with inflammatory bowel disease has led to the identification of new targets that could, in turn, drive the development of effective biological therapies.

Rationale and safety of anti-interleukin-23 and anti-interleukin-17A therapy

PURPOSE OF REVIEW

Interleukin-12 is a heterodimeric cytokine and an important mediator of the cellular immune response. The recent discovery of the novel cytokine interleukin-23 has led to a re-evaluation of interleukin-12 biology, as both cytokines use a common p40 subunit. This review discusses understanding of what distinguishes these related cytokines and the infection risks associated with targeting these cytokine pathways during treatment of inflammatory diseases.

RECENT FINDINGS

Recent work has shown that interleukin-23 stimulates the development of a distinct subset of effector T cells that produce interleukin-17A. These interleukin-17A-producing cells are critical mediators of the inflammatory response in several mouse models of autoimmunity. Although it is well established that interleukin-12 is a critical mediator of host defense, the role of the interleukin-23/interleukin-17A axis during infections has only recently been evaluated.

SUMMARY

Interleukin-12 and interleukin-23 have distinct roles in mediating host defense and autoimmune inflammation. Although targeting interleukin-12 and interleukin-23 simultaneously against the common p40 subunit is efficacious in clinical trials for human autoimmune diseases, targeting of interleukin-23 alone or the downstream effector cytokine interleukin-17A may be an effective treatment strategy for organ-specific autoimmune diseases. It is likely that targeting interleukin-23 or interleukin-17A alone, as opposed to targeting interleukin-12 and interleukin-23 together, will reduce the patients' risk of developing treatment-related infections.

Type I cytokine profiles of human naïve and memory B lymphocytes: a potential for memory cells to impact polarization

B cells bifurcating along 'type 1' or 'type 2' pathways under the influence of polarizing cytokines can, in turn, influence the direction of an immune response. Here, we compare the capacity of human B cells residing within naïve and memory compartments to participate in type 1 polarizing responses. B-cell receptor (BCR) engagement provided the main signal for interleukin (IL)-12Rbeta1 expression in the two subsets: this was potentiated by CD154 together with interferon-gamma (IFN-gamma) but inhibited by IL-12. IL-12Rbeta2 could be induced on a minority of B cells by the same signals, and also by IFN-gamma alone. WSX-1, a receptor for IL-27, was expressed in both subsets with no evidence for its regulation by the signals studied. While neither subset was capable of secreting much IL-12 p70, memory B cells could produce a small amount of IL-12 p40 on CD40 ligation. Memory B cells also, exclusively, expressed IL-23 p19 mRNA on BCR triggering. Importantly, products of appropriately stimulated memory--but not naive--B cells were shown to promote the synthesis of IFN-gamma in uncommitted T-helper cells. The data indicate an equal capacity for naïve and memory B cells to respond within a type 1 polarizing environment. Although poorly equipped for initiating type 1 responses, B cells--by virtue of the memory subset--reveal a capacity for their maintenance and amplification following T-dependent signalling.

IL-23: changing the verdict on IL-12 function in inflammation and autoimmunity

IL-12 and IL-23 are molecules mainly produced by activated accessory and antigen-presenting cells. The tools for studying the biology of IL-12 in man and laboratory rodents have greatly advanced our appreciation of the central role of this molecule in cell-mediated immunity and inflammation. In particular, IL-12 is thought to be the prime-regulator of TH1 development. Targeting what was thought to be IL-12 function in vivo, resulted in drastic amelioration of inflammation and autoimmunity firmly linking TH1 polarisation to autoimmune development. Upon discovery of IL-23 and the fact that the large subunit of IL-23 is shared by IL-12, the research community only begins to grasp that the features attributed to IL-12 and TH1 development in inflammation are, in fact, dependent on IL-23 and not on IL-12. Hence, the perception of IL-12 biology is, to a large extent, based on a mistaken identity. In this review, the authors provide an overview of their current understanding of IL-12 and IL-23 biology in inflammation and autoimmunity, and how this viewpoint has been readjusted over the past 15 years.

Anti-IL-23 therapy inhibits multiple inflammatory pathways and ameliorates autoimmune encephalomyelitis

IL-23 is a member of the IL-12 cytokine family that drives a highly pathogenic T cell population involved in the initiation of autoimmune diseases. We have shown that IL-23-dependent, pathogenic T cells produced IL-17 A, IL-17 F, IL-6, and TNF but not IFN-gamma or IL-4. We now show that T-bet and STAT1 transcription factors are not required for the initial production of IL-17. However, optimal IL-17 production in response to IL-23 stimulation appears to require the presence of T-bet. To explore the clinical efficacy of targeting the IL-23 immune pathway, we generated anti-IL-23p19-specific antibodies and tested to determine whether blocking IL-23 function can inhibit EAE, a preclinical animal model of human multiple sclerosis. Anti-IL-23p19 treatment reduced the serum level of IL-17 as well as CNS expression of IFN-gamma, IP-10, IL-17, IL-6, and TNF mRNA. In addition, therapeutic treatment with anti-IL-23p19 during active disease inhibited proteolipid protein (PLP) epitope spreading and prevented subsequent disease relapse. Thus, therapeutic targeting of IL-23 effectively inhibited multiple inflammatory pathways that are critical for driving CNS autoimmune inflammation.

The IL-23/IL-17 axis in inflammation

IL-23 induces the differentiation of naive CD4(+) T cells into highly pathogenic helper T cells (Th17/Th(IL-17)) that produce IL-17, IL-17F, IL-6, and TNF-alpha, but not IFN-gamma and IL-4. Two studies in this issue of the JCI demonstrate that blocking IL-23 or its downstream factors IL-17 and IL-6, but not the IL-12/IFN-gamma pathways, can significantly suppress disease development in animal models of inflammatory bowel disease and MS (see the related articles beginning on pages 1310 and 1317). These studies suggest that the IL-23/IL-17 pathway may be a novel therapeutic target for the treatment of chronic inflammatory diseases.

IL-23 is essential for T cell-mediated colitis and promotes inflammation via IL-17 and IL-6

Uncontrolled mucosal immunity in the gastrointestinal tract of humans results in chronic inflammatory bowel disease (IBD), such as Crohn disease and ulcerative colitis. In early clinical trials as well as in animal models, IL-12 has been implicated as a major mediator of these diseases based on the ability of anti-p40 mAb treatment to reverse intestinal inflammation. The cytokine IL-23 shares the same p40 subunit with IL-12, and the anti-p40 mAbs used in human and mouse IBD studies neutralized the activities of both IL-12 and IL-23. IL-10-deficient mice spontaneously develop enterocolitis. To determine how IL-23 contributes to intestinal inflammation, we studied the disease susceptibility in the absence of either IL-23 or IL-12 in this model, as well as the ability of recombinant IL-23 to exacerbate IBD induced by T cell transfer. Our study shows that in these models, IL-23 is essential for manifestation of chronic intestinal inflammation, whereas IL-12 is not. A critical target of IL-23 is a unique subset of tissue-homing memory T cells, which are specifically activated by IL-23 to produce the proinflammatory mediators IL-17 and IL-6. This pathway may be responsible for chronic intestinal inflammation as well as other chronic autoimmune inflammatory diseases.

Ovarian follicular concentration of IL-12, IL-15, IL-18 and p40 subunit of IL-12 and IL-23

BACKGROUND

The aim of the study was to determine the presence of interleukin (IL)-12, IL-15, IL-18 and p40 subunit of IL-12/IL-23 in follicular fluid from spontaneous cycles and the relation between the concentration of selected cytokines and IVF-embryo transfer outcome.

METHODS

IVF-embryo transfer and enzyme immunoassay (EIA) (R&D Systems, Minneapolis, MN, USA and MBL, Nagoya, Japan) were used.

RESULTS

Follicular fluid of women included in the IVF-embryo transfer procedure contained common p40 subunit of IL-12/IL-23 (median 70.1 pg/ml), IL-15 (median 1.3 pg/ml) and IL-18 (median 38.2 pg/ml). There was a significant negative correlation between follicular fluid concentrations of IL-15 and IL-18 (R=-0.392, P=0.003). Significantly higher concentrations of common p40 subunit of IL-12/IL-23 (median 79.8 pg/ml) were found in the follicular fluid taken from follicles containing oocytes, when compared with those without an oocyte (median 44.5 pg/ml, P=0.006). Patients who achieved clinical pregnancy had significantly decreased concentration of IL-15 (median 0.8 pg/ml) compared with patients without successful IVF-embryo transfer outcome (median 1.4 pg/ml, P=0.047).

CONCLUSION

Follicular fluid collected from spontaneous cycles contains detectable levels of p40 subunit of IL-12/IL-23, IL-15 and IL-18. Increased concentrations of p40 subunit of IL-12/IL-23 in follicles containing oocytes suggest an important role of this cytokine in reproduction. Possible negative value of IL-15 as a predictor of IVF-embryo transfer success remains to be determined.

Progress in tuberculosis vaccine development

The first tuberculosis vaccine candidates have reached clinical testing. Novel subunit vaccine candidates aimed at boosting previous BCG-prime vaccination and novel viable attenuated vaccine candidates aimed at substituting BCG have both completed the preclinical stage. Despite these achievements, rational vaccine design against tuberculosis has not come to an end. Novel findings in basic immunology and microbiology will advance further improvements in vaccine development. These include the potential role of crosspriming to induce more potent T-cell responses, the role of memory T cells and regulatory T cells in sustaining or curtailing optimal immune responses, respectively, as well as the involvement of cytokines in T-cell migration to nonimmunologic tissue sites and in the generation of memory. Knowledge about basic mechanisms underlying optimum protection will not only have a direct impact on future vaccine design against tuberculosis but also help in the formulation of a set of biomarkers with predictive value for vaccine efficacy assessment.

STAT3 and NF-kappaB signal pathway is required for IL-23-mediated IL-17 production in spontaneous arthritis animal model IL-1 receptor antagonist-deficient mice

IL-23 is a heterodimeric cytokine composed of a p19 subunit and the p40 subunit of IL-12. IL-23 has proinflammatory activity, inducing IL-17 secretion from activated CD4(+) T cells and stimulating the proliferation of memory CD4(+) T cells. We investigated the pathogenic role of IL-23 in CD4(+) T cells in mice lacking the IL-1R antagonist (IL-1Ra(-/-)), an animal model of spontaneous arthritis. IL-23 was strongly expressed in the inflamed joints of IL-1Ra(-/-) mice. Recombinant adenovirus expressing mouse IL-23 (rAd/mIL-23) significantly accelerated this joint inflammation and joint destruction. IL-1beta further increased the production of IL-23, which induced IL-17 production and OX40 expression in splenic CD4(+) T cells of IL-1Ra(-/-) mice. Blocking IL-23 with anti-p19 Ab abolished the IL-17 production induced by IL-1 in splenocyte cultures. The process of IL-23-induced IL-17 production in CD4(+) T cells was mediated via the activation of Jak2, PI3K/Akt, STAT3, and NF-kappaB, whereas p38 MAPK and AP-1 did not participate in the process. Our data suggest that IL-23 is a link between IL-1 and IL-17. IL-23 seems to be a central proinflammatory cytokine in the pathogenesis of this IL-1Ra(-/-) model of spontaneous arthritis. Its intracellular signaling pathway could be useful therapeutic targets in the treatment of autoimmune arthritis.

Immunological and antitumor effects of IL-23 as a cancer vaccine adjuvant

The promising, but modest, clinical results of many human cancer vaccines indicate a need for vaccine adjuvants that can increase both the quantity and the quality of vaccine-induced, tumor-specific T cells. In this study we tested the immunological and antitumor effects of the proinflammatory cytokine, IL-23, in gp100 peptide vaccine therapy of established murine melanoma. Neither systemic nor local IL-23 alone had any impact on tumor growth or tumor-specific T cell numbers. Upon specific vaccination, however, systemic IL-23 greatly increased the relative and absolute numbers of vaccine-induced CD8(+) T cells and enhanced their effector function at the tumor site. Although IL-23 specifically increased IFN-gamma production by tumor-specific T cells, IFN-gamma itself was not a primary mediator of the vaccine adjuvant effect. The IL-23-induced antitumor effect and accompanying reversible weight loss were both partially mediated by TNF-alpha. In contrast, local expression of IL-23 at the tumor site maintained antitumor activity in the absence of weight loss. Under these conditions, it was also clear that enhanced effector function of vaccine-induced CD8(+) T cells, rather than increased T cell number, is a primary mechanism underlying the antitumor effect of IL-23. Collectively, these results suggest that IL-23 is a potent vaccine adjuvant for the induction of therapeutic, tumor-specific CD8(+) T cell responses.

Human dendritic cells following Aspergillus fumigatus infection express the CCR7 receptor and a differential pattern of interleukin-12 (IL-12), IL-23, and IL-27 cytokines, which lead to a Th1 response

Aspergillus fumigatus is the most prevalent airborne fungal pathogen and causes fatal invasive aspergillosis in immunocompromised patients. Given the essential role of dendritic cells (DC) in initiating and regulating immune responses, we investigated the impact of A. fumigatus conidial infection on human DC. A. fumigatus conidia were rapidly internalized and induced the release of tumor necrosis factor alpha within the first 8 h. After A. fumigatus infection, the majority of DC underwent full maturation, although CCR7 expression was observed only in DC that had internalized the conidia. Additionally, the analysis of regulatory cytokines showed that infected DC simultaneously produced interleukin-12p70 (IL-12p70) and significant amounts of IL-10. IL-10 neutralization was not able to further increase IL-12p70 production from infected DC. Whereas the central role of IL-12 in the generation of Th1 cells has long been appreciated, recently two other members of the IL-12 family, IL-23 and IL-27, were reported to play important roles in the regulation of gamma interferon (IFN-gamma) production from naïve and memory T cells. A. fumigatus-infected DC were also able to express high levels of IL-23p19 and low levels of IL-27p28 at later stages of infection. According to this expression pattern, A. fumigatus-infected DC were able to prime IFN-gamma production of naïve T cells. Thus, this study on the expression of the new IL-12 family members controlling the Th1 response sheds light on a novel aspect of the contribution of DC to anti-Aspergillus immunity.

Interleukin 23 in Acute Inflammatory Demyelination of the Peripheral Nerve

BACKGROUND

Interleukin (IL) 23, a newly identified heterodimeric proinflammatory cytokine and a novel IL-12 family member comprising the p40 subunit of IL-12 but a different p19 subunit, has been reported to preferentially act on memory T cells and play an important role during cellular immune responses. Recent evidence suggests that IL-23 rather than IL-12 is critically involved in the pathogenesis of various immune-mediated disorders.

OBJECTIVE

To determine the role of IL-23p19 during the course of acute immune-mediated demyelinating diseases of the peripheral nervous system.

DESIGN

The sequential RNA expression of IL-23p19 in sciatic nerves from rats with experimental autoimmune neuritis, an animal model of the human Guillain-Barré syndrome (GBS), was analyzed by semiquantitative reverse transcriptase-polymerase chain reaction. Expression and distribution patterns of IL-23p19 protein were studied in sural nerve biopsies and cerebrospinal fluid samples from 5 patients with classical Guillain-Barré syndrome and 5 controls with noninflammatory neuropathies using immunohistochemistry and immunoblotting, respectively.

RESULTS

We found IL-23p19 RNA to be up-regulated prior to the onset of first clinical symptoms with peak expression levels preceding maximum disease severity during experimental autoimmune neuritis. In patients, IL-23p19 protein was detectable in cerebrospinal fluid samples from patients with Guillain-Barré syndrome, and endoneurial macrophages were identified as the cellular source of IL-23p19 in sural nerve biopsies.

CONCLUSION

Our present data indicate that IL-23 may play an important role during the early effector phase in immune-mediated demyelination of the peripheral nerve.

Diversification of T-helper-cell lineages: finding the family root of IL-17-producing cells

CD4+ T helper 1 (T(H)1) and T(H)2 cells have long been regarded as two sides of a coin in terms of adaptive immune responses. However, as I discuss here, this concept needs to be reconsidered. In particular, recent data indicate that interleukin-17 (IL-17) is produced by T(H) cells that are distinct from the traditional T(H)1- and T(H)2-cell subsets. Furthermore, the generation of these IL-17-producing CD4+ T cells from naive precursors during immune responses is not dependent on the cytokines and transcription factors that mediate T(H)1- and T(H)2-cell development. Given that IL-17 has crucial roles in regulating tissue inflammation and the development of disease in several animal models of autoimmunity, I propose that IL-17-producing CD4+ T cells represent a distinct inflammatory T(H)-cell lineage.

Selective regulatory function of Socs3 in the formation of IL-17-secreting T cells

Suppressor of cytokine signaling (Socs) 3 is a cytokine-inducible inhibitor with critical but selective cell-specific effects. We show that deficiency of Socs3 in T cells had minimal effects on differentiation of T cells to the T helper (Th) 1 or Th2 subsets; accordingly, Socs3 had no effect on IL-12-dependent signal transducer and activator of transcription (Stat) 4 phosphorylation or IL-4-dependent Stat6 phosphorylation. By contrast, Socs3 was found to be a major regulator of IL-23-mediated Stat3 phosphorylation and Th17 generation, and Stat3 directly binds to the IL-17A and IL-17F promoters. We conclude that Socs3 is an essential negative regulator of IL-23 signaling, inhibition of which constrains the generation of Th17 differentiation.

IL-23 promotes tumour incidence and growth

Chronic inflammation has long been associated with increased incidence of malignancy and similarities in the regulatory mechanisms have been suggested for more than a century. Infiltration of innate immune cells, elevated activities of matrix metalloproteases and increased angiogenesis and vasculature density are a few examples of the similarities between chronic and tumour-associated inflammation. Conversely, the elimination of early malignant lesions by immune surveillance, which relies on the cytotoxic activity of tumour-infiltrating T cells or intra-epithelial lymphocytes, is thought to be rate-limiting for the risk to develop cancer. Here we show a molecular connection between the rise in tumour-associated inflammation and a lack of tumour immune surveillance. Expression of the heterodimeric cytokine interleukin (IL)-23, but not of its close relative IL-12, is increased in human tumours. Expression of these cytokines antagonistically regulates local inflammatory responses in the tumour microenvironment and infiltration of intra-epithelial lymphocytes. Whereas IL-12 promotes infiltration of cytotoxic T cells, IL-23 promotes inflammatory responses such as upregulation of the matrix metalloprotease MMP9, and increases angiogenesis but reduces CD8 T-cell infiltration. Genetic deletion or antibody-mediated elimination of IL-23 leads to increased infiltration of cytotoxic T cells into the transformed tissue, rendering a protective effect against chemically induced carcinogenesis. Finally, transplanted tumours are growth-restricted in hosts depleted for IL-23 or in IL-23-receptor-deficient mice. Although many strategies for immune therapy of cancer attempt to stimulate an immune response against solid tumours, infiltration of effector cells into the tumour tissue often appears to be a critical hurdle. We show that IL-23 is an important molecular link between tumour-promoting pro-inflammatory processes and the failure of the adaptive immune surveillance to infiltrate tumours.