Genetic variations in the interleukin-12/interleukin-23 receptor (beta1) chain, and implications for IL-12 and IL-23 receptor structure and function

IL12RB1 allele bias in human TH cells is regulated by functional SNPs in its 3'UTR

Allele bias is an epigenetic mechanism wherein only the maternal- or paternal-derived allele of a gene is preferentially expressed. Allele bias is used by T cells to regulate expression of numerous genes, including those which govern their development and response to cytokines. Here we demonstrate that human T_H cell expression of the cytokine receptor gene IL12RB1 is subject to allele bias, and the extent to which this bias occurs is influenced by cells' differentiation status and two polymorphic sites in the IL12RB1 3'UTR. The single nucleotide polymorphisms (SNPs) at these sites, rs3746190 and rs404733, function to increase expression of their encoding allele. Modeling suggests this is due to a stabilizing effect of these SNPs on the predicted mRNA secondary structure. The SNP rs3746190 is also proximal to the predicted binding site of microRNA miR-1277, raising the possibility that miR-1277 cannot exert suppression in the presence of rs3746190. Functional experiments demonstrate, however, that miR-1277 suppression of IL12RB1 3'UTR expression-which itself has not been previously reported-is nevertheless independent of rs3746190. Collectively, these data demonstrate that rs3746190 and rs404733 are functional SNPs which regulate IL12RB1 allele bias in human T_H cells.

Inflammatory Factors: Nonobese Pediatric Obstructive Sleep Apnea and Adenotonsillectomy

Background: Inflammation is often considered relating to pediatric obstructive sleep apnea (OSA). We conducted a study investigating cytokines, including Il-17 and Il-23, in children with OSA before and after adenotonsillectomy (T&A), compared with controls. Methods: Children with OSA between age 4 and 12 receiving T&A were prospectively followed. Evaluation before and reevaluation six months after the treatment were done, including polysomnography (PSG), blood tests, and questionnaires. Blood samples were obtained to determine the values of high-sensitivity-C-reactive-protein (HS-CRP); tumor-necrosis-factor-alpha (TNF-α); and interleukin (IL)-1, 6, 10, 12, 17, and 23. We compared the results with an age-matched control group. Results: We included 55 OSA children and 32 controls. Children with OSA presented significant improvement after T&A in complaints, signs, apnea hypopnea index (AHI) (p < 0.001), mean oxygen desaturation index (p < 0.001), and mean oxygen saturation (p = 0.010). Upon entering this study, children with OSA had significantly higher cytokine levels than the controls and significant changes in HS-CRP (p = 0.013), TNF-α (p = 0.057), IL-1β (p = 0.022), IL-10 (p = 0.035), and IL-17 (p = 0.010) after T&A. Children with improved but persistently abnormal AHI did not have all cytokine levels normalized, particularly IL-23 and HS-CRP. Conclusion: Sleep-disordered breathing can persist after T&A and can continue to have a negative inflammatory effect. HS-CRP and IL-23 may serve as blood markers for the persistence of sleep-disordered breathing after T&A.

Roles of aberrant hemichannel activities due to mutant connexin26 in the pathogenesis of KID syndrome

Germline missense mutations in GJB2 encoding connexin (Cx) 26 have been found in keratitis, ichthyosis and deafness (KID) syndrome. We explored the effects of three mouse Cx26 mutants (Cx26-G12R, -G45E and -D50N) corresponding to KID syndrome-causative human mutants on hemichannel activities leading to cell death and the expression of immune response-associated genes. We analyzed the 3D images of cells expressing wild-type (WT) or mutant Cx26 molecules to demonstrate clearly the intracellular localization of Cx26 mutants and hemichannel formation. High extracellular Ca²⁺ conditions lead to the closure of gap junction hemichannels in Cx26-G12R or Cx26-G45E expressing cells, resulting in prohibition of the Cx26 mutant-induced cell death. Fluorescent dye uptake assays revealed that cells with Cx26-D50N had aberrantly high hemichannel activities, which were abolished by a hemichannel blocker, carbenoxolone and 18α-Glycyrrhetinic acid. These results further support the idea that abnormal hemichannel activities play important roles in the pathogenesis of KID syndrome. Furthermore, we revealed that the expressions of IL15, CCL5, IL1A, IL23R and TLR5 are down-regulated in keratinocytes expressing Cx26-D50N, suggesting that immune deficiency in KID syndrome expressing Cx26-D50N might be associated not only with skin barrier defects, but also with the down-regulated expression of immune response-related genes.

Inflammatory cytokines in pediatric obstructive sleep apnea

Pediatric obstructive sleep apnea (OSA) is associated with chronic systemic inflammation and with cognitive impairments. This study aimed to investigate the status of proinflammatory cytokines, particularly interleukin 17 (IL-17) and interleukin 23 (IL-23) and cognition in pediatric OSA.Controls and OSA children participated in the study. Exclusion criteria were adenotonsillectomy, heart, neurological and severe psychiatric diseases, craniofacial syndromes, and obesity. Polysomnogram was followed by serum testing for inflammatory markers and neurocognitive tests such as continuous performance task (CPT) and Wisconsin card sorting test, questionnaires, analyses of plasma high-sensitivity C-reactive protein (HS-CRP), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), interleukin 6 (IL-6), IL-17, and IL-23.Seventy-nine, 4 to 12-year-old subjects in 2 groups ended the study: 47 nonobese OSA children (mean age = 7.84 ± 0.56 years, body mass index [BMI] = 16.95 ± 0.47 kg/m, BMI z-score = 0.15 ± 0.21, and mean apnea-hypopnea index [AHI] = 9.13 ± 1.67 events/h) and 32 healthy control children (mean age = 7.02 ± 0.65 years, with BMI = 16.55 ± 0.58 kg/m, BMI z-score = -0.12 ± 0.27, and mean AHI = 0.41 ± 0.07 event/h) were enrolled. Serum cytokine analyses showed significantly higher levels of HS-CRP, IL-17, and IL-23 in OSA children (P = 0.002, P = 0.024, and P = 0.047). Regression test showed significant influence of HS-CRP, TNF-α, IL-6, IL-17, and specifically IL-23, with the continuous performance test and Wisconsin card sorting test.OSA children have abnormal levels of IL-17, an interleukin related to T helper 17 cells, a T helper cell involved in development of autoimmunity and inflammation. This high expression level may contribute to the complications of pediatric OSA; we also found a significant influence of inflammatory cytokines, particularly IL-23, on abnormal neurocognitive testing.

Variations in IL-23 and IL-25 receptor gene structure, sequence and expression associated with the two disease forms of sheep paratuberculosis

The immunopathology of paucibacillary and multibacillary sheep paratuberculosis is characterized by inflammatory T cell and macrophage responses respectively. IL-23 and IL-25 are key to the development of these responses by interaction with their complex receptors, IL-23R/IL-12RB1 and IL-17RA/IL-17RB. In humans, variations in structure, sequence and/or expression of these genes have been implicated in the different pathological forms of tuberculosis and leprosy, and in gastrointestinal inflammatory disorders such as Crohn’s disease. Sequencing has identified multiple transcript variants of sheep IL23R, IL12RB1 and IL17RB and a single IL17RA transcript. RT-qPCR assays were developed for all the identified variants and used to compare expression in the ileo-caecal lymph node of sheep with paucibacillary or multibacillary paratuberculosis and uninfected animals. With IL-23 receptor, only the IL12RB1v3 variant, which lacks the receptor activation motif was differentially expressed and was significantly increased in multibacillary disease; this may contribute to high Th2 responses. Of the IL17RB variants only full length IL17RB was differentially expressed and was significantly increased in multibacillary pathology; which may also contribute to Th2 polarization. IL17RA expression was significantly increased in paucibacillary disease. The contrast between the IL17RA and IL17RB results may indicate that, in addition to Th1 cells, Th17 T cells are also involved in paucibacillary pathology.

The introduction of RNA-DNA differences underlies interindividual variation in the human IL12RB1 mRNA repertoire

Human interleukin 12 and interleukin 23 (IL12/23) influence susceptibility or resistance to multiple diseases. However, the reasons underlying individual differences in IL12/23 sensitivity remain poorly understood. Here we report that in human peripheral blood mononuclear cells (PBMCs) and inflamed lungs, the majority of interleukin-12 receptor β1 (IL12RB1) mRNAs contain a number of RNA-DNA differences (RDDs) that concentrate in sequences essential to IL12Rβ1's binding of IL12p40, the protein subunit common to both IL-12 and IL-23. IL12RB1 RDDs comprise multiple RDD types and are detectable by next-generation sequencing and classic Sanger sequencing. As a consequence of these RDDs, the resulting IL12Rβ1 proteins have an altered amino acid sequence that could not be predicted on the basis of genomic DNA sequencing alone. Importantly, the introduction of RDDs into IL12RB1 mRNAs negatively regulates IL12Rβ1's binding of IL12p40 and is sensitive to activation. Collectively, these results suggest that the introduction of RDDs into an individual's IL12RB1 mRNA repertoire is a novel determinant of IL12/23 sensitivity.

IL12Rβ1ΔTM is a secreted product of il12rb1 that promotes control of extrapulmonary tuberculosis

IL12RB1 is a human gene that is important for resistance to Mycobacterium tuberculosis infection. IL12RB1 is expressed by multiple leukocyte lineages, and encodes a type I transmembrane protein (IL12Rβ1) that associates with IL12p40 and promotes the development of host-protective T(H)1 cells. Recently, we observed that il12rb1—the mouse homolog of IL12RB1—is alternatively spliced by leukocytes to produce a second isoform (IL12Rβ1ΔTM) that has biological properties distinct from IL12Rβ1. Although the expression of IL12Rβ1ΔTM is elicited by M. tuberculosis in vivo, and its overexpression enhances IL12p40 responsiveness in vitro, the contribution of IL12Rβ1ΔTM to controlling M. tuberculosis infection has not been tested. Here, we demonstrate that IL12Rβ1ΔTM represents a secreted product of il12rb1 that, when absent from mice, compromises their ability to control M. tuberculosis infection in extrapulmonary organs. Furthermore, elevated M. tuberculosis burdens in IL12Rβ1ΔTM-deficient animals are associated with decreased lymph node cellularity and a decline in TH1 development. Collectively, these data support a model wherein IL12Rβ1ΔTM is a secreted product of il12rb1 that promotes resistance to M. tuberculosis infection by potentiating T(H) cells response to IL-12.

Role of IL-23 in the pathogenesis of psoriasis: a novel potential therapeutic target?

INTRODUCTION

Psoriasis is a chronic inflammatory skin disorder determined by the activation of several immune cells and resident tissue cells. Various cytokines mediate inflammatory signals, including IL-23, which is an important factor involved in the differentiation of T helper (Th17) cells.

AREAS COVERED

Increasing evidence suggests that IL-23 is a central cytokine to the pathogenesis of psoriasis. An overview on both experimental and human data will be reported in order to support the hypothesis of a key pathogenic role of IL-23/Th17 axis.

EXPERT OPINION

Targeting IL-23 might be a more selective, valid and effective therapeutic approach, which, potentially, may show important advantages in terms of long-term efficacy and safety in the treatment of psoriasis.

Increasing the ex vivo antigen-specific IFN-γ production in subpopulations of T cells and NKp46+ cells by anti-CD28, anti-CD49d and recombinant IL-12 costimulation in cattle vaccinated with recombinant proteins from Mycobacterium avium subspecies paratuberculosis

T cells, which encounter specific antigen (Ag), require additional signals to mount a functional immune response. Here, we demonstrate activation of signal 2, by anti-CD28 mAb (aCD28) and other costimulatory molecules (aCD49d, aCD5), and signal 3, by recombinant IL-12, enhance Ag-specific IFN-γ secretion by CD4, CD8, γδ T cells and NK cells. Age matched male jersey calves, experimentally infected with Mycobacterium avium subsp. paratuberculosis (MAP), were vaccinated with a cocktail of recombinant MAP proteins or left unvaccinated. Vaccine induced ex vivo recall responses were measured through Ag-specific IFN-γ production by ELISA and flow cytometry. There was a significant increase in production of IFN-γ by T cell subsets or NKp46+ cells cultured in the presence of Ag and aCD28/aCD49d. The increase was accompanied by an increase in the integrated median fluorescence intensity (iMFI) of activated T cells. Addition of rIL-12 induced a significant additive effect leading to a maximum increase in responder frequency of Ag-specific T cell subsets or NKp46+ cells with a heavy bias toward IFN-γ production by CD4 T cells. We provide the first description of using aCD28/aCD49d costimulation to potentiate an Ag-specific increase in the production of IFN-γ in bovine immunology. The study also shows the degree of signaling in T cells is regulated by the costimulatory environment.

IL-12Rβ1 deficiency: mutation update and description of the IL12RB1 variation database

IL-12Rβ1 deficiency is an autosomal recessive disorder characterized by predisposition to recurrent and/or severe infections caused by otherwise poorly pathogenic mycobacteria and salmonella. IL-12Rβ1 is a receptor chain of both the IL-12 and the IL-23 receptor and deficiency of IL-12Rβ1 thus abolishes both IL-12 and IL-23 signaling. IL-12Rβ1 deficiency is caused by bi-allelic mutations in the IL12RB1 gene. Mutations resulting in premature stop codons, such as nonsense, frame shift, and splice site mutations, represent the majority of IL-12Rβ1 deficiency causing mutations (66%; 46/70). Also every other morbid mutation completely inactivates the IL-12Rβ1 protein. In addition to disease-causing mutations, rare and common variations with unknown functional effect have been reported in IL12RB1. All these variants have been deposited in the online IL12RB1 variation database (www.LOVD.nl/IL12RB1). In this article, we review the function of IL-12Rβ1 and molecular genetics of human IL12RB1.

Cytokines in radiobiological responses: a review

Cytokines function in many roles that are highly relevant to radiation research. This review focuses on how cytokines are structurally organized, how they are induced by radiation, and how they orchestrate mesenchymal, epithelial and immune cell interactions in irradiated tissues. Pro-inflammatory cytokines are the major components of immediate early gene programs and as such can be rapidly activated after tissue irradiation. They converge with the effects of ionizing radiation in that both generate free radicals including reactive oxygen and nitrogen species (ROS/RNS). "Self" molecules secreted or released from cells after irradiation feed the same paradigm by signaling for ROS and cytokine production. As a result, multilayered feedback control circuits can be generated that perpetuate the radiation tissue damage response. The pro-inflammatory phase persists until such times as perceived challenges to host integrity are eliminated. Antioxidant, anti-inflammatory cytokines then act to restore homeostasis. The balance between pro-inflammatory and anti-inflammatory forces may shift to and fro for a long time after radiation exposure, creating waves as the host tries to deal with persisting pathogenesis. Individual cytokines function within socially interconnected groups to direct these integrated cellular responses. They hunt in packs and form complex cytokine networks that are nested within each other so as to form mutually reinforcing or antagonistic forces. This yin-yang balance appears to have redox as a fulcrum. Because of their social organization, cytokines appear to have a considerable degree of redundancy and it follows that an elevated level of a specific cytokine in a disease situation or after irradiation does not necessarily implicate it causally in pathogenesis. In spite of this, "driver" cytokines are emerging in pathogenic situations that can clearly be targeted for therapeutic benefit, including in radiation settings. Cytokines can greatly affect intrinsic cellular radiosensitivity, the incidence and type of radiation tissue complications, bystander effects, genomic instability and cancer. Minor and not so minor, polymorphisms in cytokine genes give considerable diversity within populations and are relevant to causation of disease. Therapeutic intervention is made difficult by such complexity; but the potential prize is great.

Inflammatory signals direct expression of human IL12RB1 into multiple distinct isoforms

IL12RB1 is essential for human resistance to multiple intracellular pathogens, including Mycobacterium tuberculosis. In its absence, the proinflammatory effects of the extracellular cytokines IL-12 and IL-23 fail to occur, and intracellular bacterial growth goes unchecked. Given the recent observation that mouse leukocytes express more than one isoform from il12rb1, we examined whether primary human leukocytes similarly express more than one isoform from IL12RB1. We observed that human leukocytes express as many as 13 distinct isoforms, the relative levels of each being driven by inflammatory stimuli both in vitro and in vivo. Surprisingly, the most abundant isoform present before stimulation is a heretofore uncharacterized intracellular form of the IL-12R (termed "isoform 2") that presumably has limited contact with extracellular cytokine. After stimulation, primary PBMCs, including the CD4(+), CD8(+), and CD56(+) lineages contained therein, alter the splicing of IL12RB1 RNA to increase the relative abundance of isoform 1, which confers IL-12/IL-23 responsiveness. These data demonstrate both a posttranscriptional mechanism by which cells regulate their IL-12/IL-23 responsiveness, and that leukocytes primarily express IL12RB1 in an intracellular form located away from extracellular cytokine.

Impact of cytokine and cytokine receptor gene polymorphisms on cellular immunity after smallpox vaccination

We explored associations between SNPs in cytokine/cytokine receptor genes and cellular immunity in subjects following primary smallpox vaccination. We also analyzed the genotype-phenotype associations discovered in the Caucasian subjects among a cohort of African-Americans. In Caucasians we found 277 associations (p<0.05) between gene SNPs and inter-individual variations in IFN-α, IL-12p40, IL-1β, IL-2, and TNF-α secretion levels. A collection of SNPs in the IL1RN, IL2RB, IL4R, IL6, IL10RB, IL12A, and IL12RB2 genes had consistent associations among both Caucasians and African-Americans. A regulatory SNP (rs452204) in the IL1RN gene was significantly associated with higher levels of IL-2 secretion in an allele dose-dependent manner in both race groups (p=0.05 for Caucasians and p=0.002 for African-Americans). IL12RB2 polymorphism rs3790567 was associated with a dose-related decrease in IL-1β secretion (p=0.009 for Caucasians and p=0.01 for African-Americans). Our results demonstrate that variations in smallpox vaccine-induced cytokine responses are modulated by genetic polymorphisms in cytokine and cytokine receptor genes.

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.

Rapid multiplex high resolution melting method to analyze inflammatory related SNPs in preterm birth

Background

Complex traits like cancer, diabetes, obesity or schizophrenia arise from an intricate interaction between genetic and environmental factors. Complex disorders often cluster in families without a clear-cut pattern of inheritance. Genomic wide association studies focus on the detection of tens or hundreds individual markers contributing to complex diseases. In order to test if a subset of single nucleotide polymorphisms (SNPs) from candidate genes are associated to a condition of interest in a particular individual or group of people, new techniques are needed. High-resolution melting (HRM) analysis is a new method in which polymerase chain reaction (PCR) and mutations scanning are carried out simultaneously in a closed tube, making the procedure fast, inexpensive and easy. Preterm birth (PTB) is considered a complex disease, where genetic and environmental factors interact to carry out the delivery of a newborn before 37 weeks of gestation. It is accepted that inflammation plays an important role in pregnancy and PTB.

Methods

Here, we used real time-PCR followed by HRM analysis to simultaneously identify several gene variations involved in inflammatory pathways on preterm labor. SNPs from TLR4, IL6, IL1 beta and IL12RB genes were analyzed in a case-control study. The results were confirmed either by sequencing or by PCR followed by restriction fragment length polymorphism.

Results

We were able to simultaneously recognize the variations of four genes with similar accuracy than other methods. In order to obtain non-overlapping melting temperatures, the key step in this strategy was primer design. Genotypic frequencies found for each SNP are in concordance with those previously described in similar populations. None of the studied SNPs were associated with PTB.

Conclusions

Several gene variations related to the same inflammatory pathway were screened through a new flexible, fast and non expensive method with the purpose of analyzing their association to PTB. It can easily be used for simultaneously analyze any set of SNPs, either as the first choice for new association studies or as a complement to large-scale genotyping analysis. Given that inflammatory pathway is in the base of several diseases, it is potentially useful to analyze a broad range of disorders.

Interleukin-23 as a potential therapeutic target for rheumatoid arthritis

Cytokine-mediated immunity plays a crucial role in the pathogenesis of various autoimmune diseases, including rheumatoid arthritis (RA). Increasing evidence has revealed the importance of IL-23, which closely resembles IL-12 structurally and immunologically, in linking innate and adaptive immunity. IL-23, a newly identified heterodimeric pro-inflammatory cytokine, is composed of a p40 subunit in common with IL-12 and a unique p19 subunit. Recent evidence suggests that IL-23, rather than IL-12, is the crucial factor in the pathogenesis of various immune-mediated disorders. In addition, recent studies have explored the role of IL-23 in patients with RA. An elevated expression of IL-23 has been demonstrated in the synovial fibroblasts and plasma of patients with RA. Moreover, an association between IL-23 and IL-23R polymorphisms with susceptibility to RA has been reported. Therefore, the targeting of IL-23 or the IL-23 receptor has been proposed as a potential therapeutic approach for RA. In this review we will discuss the biological features of IL-23, and summarize recent advances in our understanding of the role of IL-23 in the pathogenesis and treatment of RA.

Identification of single nucleotide polymorphisms in the bovine interleukin-12 and interleukin-23 receptor genes and their associations with health and production traits in Holstein cows

Interleukin-12 (IL-12) and interleukin-23 (IL-23) are proinflammatory cytokines produced by macrophages and dendritic cells in response to infection with intracellular pathogens. The IL-12 receptor (IL-12R) is a heterodimer composed of 2 subunits, β1 and β2. The IL-23 receptor (IL-23R) is a heterodimer composed of the IL-12Rβ1 subunit and a unique IL-23R subunit. Given the importance of IL-12 and IL-23 for modulating inflammation and the host immune response, the IL-12 and IL-23 receptor genes may be suitable candidate genes for studying disease resistance in dairy cattle. We hypothesize that single nucleotide polymorphisms (SNP) exist within these genes and that they contribute to variation in health and production traits in dairy cattle. To investigate this, a selective DNA pool was constructed using bull semen based on the estimated breeding values for somatic cell score (SCS), an indicator trait used to achieve genetic improvement for resistance to mastitis. Gene segments were amplified from this pool by PCR and the amplicons were sequenced to reveal SNP. A total of 10 SNP, including 2 in IL-12Rβ1, 5 in IL-12Rβ2, and 3 in IL-23R were identified. The SNP (n=5) were found in the 5' untranslated region (UTR) putative promoter regions of the genes, and SNP IL-23R c.1714A>C was a nonsynonymous SNP. Canadian Holstein bulls (n=492) were genotyped using Sequenom MassARRAY (Sequenom Inc., San Diego, CA). No association was found with SCS based on bull deregressed estimated breeding values for SCS; however, associations of SNP in the IL-12Rβ2 gene (c.-511A>G, c.87A>G, c.2957A>C) were found with milk and protein yield. Further investigation will be required to elucidate the biological and practical relevance of these SNP.

Enhancing sensitivity of detection of immune responses to Mycobacterium leprae peptides in whole-blood assays

Although worldwide leprosy prevalence has been reduced considerably following multidrug therapy, new case detection rates remain relatively stable, suggesting that transmission of infection still continues. This calls for new efforts, among which is development of assays that can identify subclinical/early-stage Mycobacterium leprae-infected subjects, a likely source of transmission. Areas in which leprosy is endemic often lack sophisticated laboratories, necessitating development of field-friendly immunodiagnostic tests for leprosy, like short-term whole-blood assays (WBA). In classical, peripheral blood mononuclear cell (PBMC)-based gamma interferon (IFN-gamma) release assays, M. leprae peptides have been shown to discriminate in a more specific fashion than M. leprae proteins between M. leprae-exposed contacts and patients as opposed to healthy controls from the same area of endemicity. However, peptides induced significantly lower levels of IFN-gamma than did proteins, particularly when whole blood was used. Therefore, possibilities of specifically enhancing IFN-gamma production in response to M. leprae peptides in 24-h WBA were sought by addition of various cytokines and antibodies or by mannosylation of peptides. In addition, other cytokines and chemokines were analyzed as potential biomarkers in WBA. We found that only interleukin 12 (IL-12), not other costimulants, increased IFN-gamma production in WBA while maintaining M. leprae peptide specificity, as evidenced by lack of increase of IFN-gamma in control samples stimulated with IL-12 alone. The IL-12-induced increase in IFN-gamma was mainly mediated by CD4+ T cells that did not produce IL-2 or tumor necrosis factor (TNF). Mannosylation further allowed the use of 100-fold-less peptide. Although not statistically significantly, macrophage inflammatory protein 1beta (MIP-1beta) and macrophage c protein 1 (MCP-1) levels specific for M. leprae peptide tended to be increased by IL-12. IP-10 production was also found to be a useful marker of M. leprae peptide responses, but its production was enhanced by IL-12 nonspecifically. We conclude that IFN-gamma-based WBA combined with IL-12 represents a more sensitive and robust assay for measuring reactivity to M. leprae peptides.

SNP/haplotype associations in cytokine and cytokine receptor genes and immunity to rubella vaccine

An effective immune response to vaccination is, in part, a complex interaction of alleles of multiple genes regulating cytokine networks. We conducted a genotyping study of Th1/Th2/inflammatory cytokines/cytokine receptors in healthy children (n = 738, 11-19 years) to determine associations between individual single-nucleotide polymorphisms (SNPs)/haplotypes and immune outcomes after two doses of rubella vaccine. SNPs (n = 501) were selected using the ldSelect-approach and genotyped using Illumina GoldenGate and TaqMan assays. Rubella-IgG levels were measured by immunoassay and secreted cytokines by ELISA. Linear regression and post hoc haplotype analyses were used to determine associations between single SNPs/haplotypes and immune outcomes. Increased carriage of minor alleles for the promoter SNPs (rs2844482 and rs2857708) of the TNFA gene were associated with dose-related increases in rubella antibodies. IL-6 secretion was co-directionally associated (p < or = 0.01) with five intronic SNPs in the TNFRSF1B gene in an allele dose-related manner, while five promoter/intronic SNPs in the IL12B gene were associated with variations in IL-6 secretion. TNFA haplotype AAACGGGGC (t-statistic = 3.32) and IL12B promoter haplotype TAG (t-statistic = 2.66) were associated with higher levels of (p < or = 0.01) rubella-IgG and IL-6 secretion, respectively. We identified individual SNPs/haplotypes in TNFA/TNFRSF1B and IL12B genes that appear to modulate immunity to rubella vaccination. Identification of such "genetic fingerprints" may predict the outcome of vaccine response and inform new vaccine strategies.

Mycobacterium tuberculosis infection induces il12rb1 splicing to generate a novel IL-12Rbeta1 isoform that enhances DC migration

RNA splicing is an increasingly recognized regulator of immunity. Here, we demonstrate that after Mycobacterium tuberculosis infection (mRNA) il12rb1 is spliced by dendritic cells (DCs) to form an alternative (mRNA) il12rb1Δtm that encodes the protein IL-12Rβ1ΔTM. Compared with IL-12Rβ1, IL-12Rβ1ΔTM contains an altered C-terminal sequence and lacks a transmembrane domain. Expression of IL-12Rβ1ΔTM occurs in CD11c⁺ cells in the lungs during M. tuberculosis infection. Selective reconstitution of il12rb1^−/− DCs with (mRNA) il12rb1 and/or (mRNA) il12rb1Δtm demonstrates that IL-12Rβ1ΔTM augments IL-12Rβ1-dependent DC migration and activation of M. tuberculosis-specific T cells. It cannot mediate these activities independently of IL12Rβ1. We hypothesize that M. tuberculosis-exposed DCs express IL-12Rβ1ΔTM to enhance IL-12Rβ1-dependent migration and promote M. tuberculosis–specific T cell activation. IL-12Rβ1ΔTM thus represents a novel positive-regulator of IL12Rβ1-dependent DC function and of the immune response to M. tuberculosis.

Antisense-mediated exon skipping to correct IL-12Rbeta1 deficiency in T cells

Patients with Mendelian susceptibility to mycobacterial disease have severe, recurrent life-threatening infections with otherwise poorly pathogenic mycobacteria and salmonellae. The extreme susceptibility is the result of genetic defects in the interleukin-12/interferon-gamma (IL-12/IFN-gamma) pathway. The infections are difficult to treat, and therapeutic options are limited. We explored the feasibility of antisense-mediated exon skipping as therapy for Mendelian susceptibility to mycobacterial disease with cells from a complete IL-12Rbeta1(-/-) patient. Expression constructs were first studied to determine whether IL12RB1 lacking exon 2 encodes a functional protein. The IL-12Rbeta1 expression construct lacking exon 2 was expressed on T cells. On IL-12 or IL-23 stimulation, this construct phosphorylated similar amounts of STAT1, STAT3, and STAT4 and induced similar amounts of IFN-gamma compared with a normal IL-12Rbeta1 construct. Antisense oligonucleotides (AONs) directed at exon 2 resulted in transcripts lacking exon 2 in both controls' and patients' T cells. In IL-12Rbeta1(-/-) cells, skipping of exon 2 led to expression of IL-12Rbeta1 on the cell surface and responsiveness to IL-12. We showed that IL12RB1 lacking exon 2 encodes a functional IL-12Rbeta1. We demonstrated that T cells can be highly efficiently transduced with AONs and are amenable to antisense-mediated exon skipping. Furthermore, we showed that exon skipping (partly) corrects the IL-12Rbeta1 deficiency in patients' cells.

Toll-like receptor 7 mitigates lethal West Nile encephalitis via interleukin 23-dependent immune cell infiltration and homing

West Nile virus (WNV), a mosquito-transmitted single-stranded RNA (ssRNA) flavivirus, causes human disease of variable severity. We investigated Toll-like receptor 7-deficient (Tlr7(-/-)) and myeloid differentiation factor 88-deficient (Myd88(-/-)) mice, which both have defective recognition of ssRNA, and found increased viremia and susceptibility to lethal WNV infection. Despite increased tissue concentrations of most innate cytokines, CD45(+) leukocytes and CD11b(+) macrophages failed to home to WNV-infected cells and infiltrate into target organs of Tlr7(-/-) mice. Tlr7(-/-) mice and macrophages had reduced interleukin-12 (IL-12) and IL-23 responses after WNV infection, and mice deficient in IL-12 p40 and IL-23 p40 (Il12b(-/-)) or IL-23 p19 (Il23a(-/-)), but not IL-12 p35 (Il12a(-/-)), responded similarly to Tlr7(-/-) mice, with increased susceptibility to lethal WNV encephalitis. Collectively, these results demonstrate that TLR7 and IL-23-dependent WNV responses represent a vital host defense mechanism that operates by affecting immune cell homing to infected target cells.

Identification and characterization of multiple splice forms of the human interleukin-23 receptor alpha chain in mitogen-activated leukocytes

The signalling of interleukin-23 (IL-23) and its receptor (IL-23R) is a key element in the differentiation of T cells to the Th17 phenotype. Here, we present the identification and characterization of human IL23R splice variants resulting from alternative splicing of the IL23R mRNA, from activated human leukocytes, following the analysis of IL23R cDNA. Twenty-four different IL23R transcripts were observed in this study, which may potentially lead to an alteration in the protein coding region of IL-23R alpha. Consequently, by analysing amino acid sequences deduced from alternatively spliced mRNA sequences, four different putative premature early termination forms of IL-23R alpha: (1) a very short 'IL-23R alpha', (2) an IL-23R alpha containing only the extracellular region, (3) a IL-23R alpha with truncated intracellular domain and (4) in-frame exon-skipping causing changes to the extracellular region of the IL-23R alpha were revealed. These changes may affect the function of IL-23R by altering the ligand-binding interaction, producing a soluble form of the receptor to act as a decoy receptor and/or modify the IL-23/IL-23R signalling, respectively. Taken together, identification of potentially functional splice variants of IL23R underscores the biological diversity of the IL23R gene and will aid in the understanding of the gene's function in normal and pathological conditions.

Interleukin-23: immunological roles and clinical implications

Increasing evidence has revealed the importance of IL-23, which closely resembles IL-12 both structurally and immunologically, in linking innate and adaptive immunity. IL-23, produced by activated type 1 macrophages and dendritic cells (DC), possesses unique roles in the differentiation and expansion of memory T cells. IL-23 has been associated with several inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease (IBD) and Helicobacter pylori associated gastritis, mainly due to its capacity to induce a strong Th1 type immune response. IL-23 is also associated with Th17 responses and the cytokine produced by the antigen presenting cells (APC), i.e. IL-12 vs IL-23 determines in part if a response is Th1 or Th17. Recent studies have also associated chronic inflammatory diseases such as IBD, psoriasis and myocardial infarction with polymorphisms of the IL-23 receptor complex. The current review focuses on the immunological role of IL-23 and possible therapeutic avenues for inflammatory diseases.

Human leukocyte antigen and cytokine receptor gene polymorphisms associated with heterogeneous immune responses to mumps viral vaccine

OBJECTIVES

Mumps outbreaks continue to occur throughout the world, including in highly vaccinated populations. Vaccination against mumps has been successful; however, humoral and cellular immune responses to mumps vaccines vary significantly from person to person. We set out to assess whether HLA and cytokine gene polymorphisms are associated with variations in the immune response to mumps viral vaccine.

METHODS

To identify genetic factors that might contribute to variations in mumps vaccine-induced immune responses, we performed HLA genotyping in a group of 346 healthy schoolchildren (12-18 years of age) who previously received 2 doses of live mumps vaccine. Single-nucleotide polymorphisms (minor allele frequency of >5%) in cytokine and cytokine receptor genes were genotyped for a subset of 118 children.

RESULTS

Median values for mumps-specific antibody titers and lymphoproliferative stimulation indices were 729 IU/mL and 4.8, respectively. Girls demonstrated significantly higher mumps antibody titers than boys, indicating gender-linked genetic differences in humoral immune response. Significant associations were found between the HLA-DQB1*0303 alleles and lower mumps-specific antibody titers. An interesting finding was the association of several HLA class II alleles with mumps-specific lymphoproliferation. Alleles of the DRB1 (*0101, *0301, *0801, *1001, *1201, and *1302), DQA1 (*0101, *0105, *0401, and *0501), and DQB1 (*0201, *0402, and *0501) loci were associated with significant variations in lymphoproliferative immune responses to mumps vaccine. Additional associations were observed with single-nucleotide polymorphisms in the interleukin-10RA, interleukin-12RB1, and interleukin-12RB2 cytokine receptor genes. Minor alleles for 4 single-nucleotide polymorphisms within interleukin-10RA and interleukin-12RB genes were associated with variations in humoral and cellular immune responses to mumps vaccination.

CONCLUSIONS

These data suggest the important role of HLA and immunoregulatory cytokine receptor gene polymorphisms in explaining variations in mumps vaccine-induced immune responses.

Association of IL12RB1 polymorphisms with susceptibility to and severity of tuberculosis in Japanese: a gene-based association analysis of 21 candidate genes

Tuberculosis (TB) is the second commonest cause of death from infectious disease after HIV/AIDS worldwide. Association studies have revealed that host genetic factors, such as human leukocyte antigen and solute carrier family 11 member A1 (NRAMP1), play roles in susceptibility to TB. To identify host genetic factors involved in the susceptibility to TB in Japanese, we performed a gene-based association analysis of 21 candidate genes on 87 TB patients and 265 controls using marker single nucleotide polymorphisms (SNPs). For the genes with two or more marker SNPs exhibiting significant allele association, we subsequently analysed the association between adjacent coding SNPs (cSNPs) and TB. Among a total of 118 marker SNPs, 3 of IL1B and 2 of IL12RB1 showed association with TB. Non-synomymous cSNPs were not identified in IL1B. Association studies on four non-synomymous cSNPs of IL12RB1 (641A/G, 1094T/C, 1132C/G, 1573G/A) in linkage disequilibrium showed that three of them (641A/G, 1094T/C, 1132C/G) were significantly associated with the development of TB. Haplotype analysis on the four cSNPs demonstrated that frequency of ATGG haplotype was significantly lower in TB patients than in controls. When TB patients were divided into two subgroups according to the severity of lung disease, advanced subgroup showed a prominent association with 641A/G, 1094T/C and 1132C/G SNPs. These data suggested that genetic variants of IL12RB1, at least in part, confer genetic susceptibility to TB, and are associated with the progression of the disease, in Japanese.

Association of polymorphisms in IL-12/IFN-gamma pathway genes with susceptibility to pulmonary tuberculosis in Indonesia

Upon infection with mycobacteria the IL-12/IFN-gamma axis plays an essential role in the activation of cell-mediated immunity required for the elimination of pathogens. Mutations in genes of the IL-12/IFN-gamma axis are known to cause extreme susceptibility to infection with environmental mycobacteria, and subtle variations in these genes may influence susceptibility to more virulent mycobacteria. We analyzed the distribution of polymorphisms in four essential genes from the IL-12/IFN-gamma axis, IL12B, IL12RB1, IFNG and IFNGR1, in 382 pulmonary tuberculosis patients and 437 healthy controls from an endemic region in Jakarta, Indonesia. The IL12RB1 gene was sequenced in a subset of individuals. Nine known single nucleotide polymorphisms (SNPs) and two new silent variations, 135G>A and 1056C>T, were detected in IL12RB1. Six functional SNPs (-2C>T, 467G>A, 641A>G, 1312C>T, 1573G>A, 1781G>A) in IL12RB1, an IL12B promoter insertion/deletion polymorphism and CA repeats in IFNG and IFNGR1 were analyzed in the cohort. The IFNGR1 allele CA(12) (p=0.004) and genotype CA(12)/CA(12) (p=0.01; OR 0.5) were associated with protection from pulmonary tuberculosis. Interestingly, IL12B promoter heterozygosity was associated with protection from tuberculosis in BCG-vaccinated individuals (p=0.03; OR=0.6). This new finding supports the role that IL-23-of which IL12B encodes a subunit--plays in generation of memory T cells.

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.

Genetic evidence for the existence of interleukin-23 and for variation in the interleukin-12 and interleukin-12 receptor genes in the horse

Immune loci, characterized by features reflecting their role in defense reactions and consequently related to evolutionary mechanisms, including polymorphisms or association with disease are suitable candidates for comparative analysis. Interleukin-12 and related cytokines are key molecules regulating natural and specific immune responses. In this study, we analyzed four horse IL12-related genes: IL23p19, IL12Rbeta2, IL12p40, and IL12p35. Genomic nucleotide sequence of the horse IL23 p19 sub-unit encoding gene was determined. The horse IL23p19 gene consists of four exons; its total mRNA length is 1004 bp, with a coding region of 579 bp. The predicted amino acid sequence of the horse IL23p19 sub-unit showed 88.0% sequence identity with the human sequence. A partial genomic sequence highly homologous to human IL12Rbeta2 suggesting existence of this gene in the horse was retrieved. Single nucleotide polymorphisms (SNPs) were identified in all four genes analyzed. PCR-RFLP genotyping was developed for selected SNPs. Inter-breed differences in allele and genotype frequencies were observed in IL12p35 SNP 242. The results showed that horse IL12-related genes are comparable to their counterparts in other mammalian species in terms of their structure and their genetic variation.

Identification and functional characterization of a novel interleukin 17 receptor: a possible mitogenic activation through ras/mitogen-activated protein kinase signaling pathway

Interleukin-17 receptor (IL-17R) is increasingly emerged as a distinct receptor family functioning in diverse cellular processes including inflammation and cancer. In this study, we uncovered a novel member of IL-17R from mouse tissue that was named mouse IL-17RE (mIL-17R). Mouse IL-17RE cDNA is composed of at least 14 exons and presents at least 6 spliced isoforms (mIL-17RE1-6) with a molecular weight ranging from 34.2 to 70.1 kD. Mouse IL-17RE is expressed in limited tissues such as lung, kidney, stomach, intestine and testis, etc., and is mainly localized in the cytoplasm and on cell membrane. IL-17RE can also be detected in numerous tumor cell lines. Importantly, a mitogenic effect was detected in BaF3 cells stably transfected with the chimeric receptor fused by the ectodomain of erythropoietin receptor (EPOR) with the transmembrane and endomain of IL-17RE in a serum-dependent but EPO-independent manner. Moreover, ERK1/2 phosphorylation was significantly up-regulated as the dose of mIL-17RE increased. Specific RNAi targeting at mIL-17RE dramatically inhibited the activation of ERK1/2, indicating that mIL-17RE could functionally activate RAS/MAPK signaling pathway. Using dominant negative MEK (Dn-MEK) or RAS (Dn-RAS) as a signaling blocker, we were able to show that mIL-17RE probably activated RAS/MAPK signaling at or upstream of RAS. Overall, our results strongly indicate that mIL-17RE may belong to a novel growth-receptor like molecule that has the capability to support cellular mitogenesis through RAS/MAPK pathway.

Molecular complementation of IL-12Rβ1 deficiency reveals functional differences between IL-12Rβ1 alleles including partial IL-12Rβ1 deficiency

Patients with mutations in IL12RB1, the gene encoding IL-12Rbeta1, suffer from combined IL-12R/IL-23R deficiency and are unusually susceptible to nontuberculous mycobacteria and salmonellae. The functional effects of amino acid changes in IL-12Rbeta1, however, have not been determined at the molecular level. Molecular complementation studies are essential to demonstrate how structural amino acid changes affect IL-12Rbeta1 function, and whether functionally different IL-12Rbeta1 alleles can be distinguished. Thirteen different IL-12Rbeta1 alleles, including 11 amino acid substitutions and the two major haplotypes (214Q-365M-378G and 214R-365T-378R), were retrovirally transduced in IL-12Rbeta1 deficient human T cells. We provide functional evidence that L77P, R173P, C186S, R213W and Y367C are deleterious mutations leading to non-functional proteins. Conversely, S74R, R156H, H438Y, A525T and G594E are fully functional IL-12Rbeta1 variants. The C198R mutation leads to a partially functional IL-12Rbeta1, representing the first molecularly proven partial IL-12Rbeta1 deficiency. Interleukin-12 (IL-12) induced not only Interferon-gamma but also IL-10 in all responder but not in null-mutant alleles, with intermediate levels in C198R. The QMG allele was found to be a higher IL-12 responder allele compared with the RTR allele. These results have implications for understanding IL-12R/IL-23R structure-function and the role of IL-12R/IL-23R in human disease.

Association of the IL12RB1 promoter polymorphisms with increased risk of atopic dermatitis and other allergic phenotypes

Atopic dermatitis (AD) is frequently associated with eosinophilia, highly elevated immunoglobulin E (IgE) levels and increased levels of T-helper 2-type (Th2) cytokines in skin lesions due to infiltrating T cells. Interleukin-12 (IL-12), in combination with interferon-gamma (IFN-gamma), inhibits IgE synthesis and Th2 cell function. As the IFN-gamma-inducing cytokines IL-12 and IL-23 utilize IL-12Rbeta1 as part of their receptors, it is possible that polymorphic variants of the IL-12Rbeta1 (IL12RB1) gene might determine an individual's susceptibility to AD. Here, we carried out a systemic search for genetic variants of the human IL12RB1 in Japanese subjects and identified 48 genetic variants. In a case-control association study, we found that promoter polymorphisms -111A/T and -2C/T were significantly associated with an increased risk of AD under a recessive model. The -111T-allele frequency in the independent population of child asthmatics was also much higher than that in the control group. In addition, the -111T/T genotype was progressively more common in AD with high total serum IgE levels in an IgE-level-dependent manner. Deletion analysis of the IL12RB1 promoter suggested that the -265 to -104 region that contained the -111A/T polymorphic site harbored an important regulatory element. Furthermore, we showed that the -111A/T substitution appeared to cause decreased gene transcriptional activity such that cells from -111A/A individuals exhibited higher IL12RB1 mRNA levels than those from -111T allele carriers. Our results suggested that in individuals with the -111T/T genotype, reduced IL-12Rbeta1 expression may lead to increased Th2 cytokine production in the skin and contribute to the development of AD and other subsequent allergic diseases.

A review of the role of proinflammatory cytokines in labor and noninfectious preterm labor

The prevention of preterm labor has the potential to reduce newborn morbidity and mortality by decreasing the incidence of preterm birth. Half of all preterm births occur in women with no known clinical risk factors. Labor onset and progress is multifactorial, and we are just beginning to understand the role of cytokines in uterine activity. The purpose of this article is to review the role of cytokines in labor and preterm labor not associated with infection and to provide implications for research and practice.

Intranasal interleukin-12 treatment promotes antimicrobial clearance and survival in pulmonary Francisella tularensis subsp. novicida infection

Francisella tularensis is a highly virulent facultative intracellular bacterium and is considered a potential biological warfare agent. Inhalation tularemia can lead to the development of bronchopneumonia, which is frequently fatal without medical intervention. Treatment strategies that directly target the respiratory mucosa may extend the efficacy of therapy, particularly for the medical management of acute aerosol exposure. To this end, we describe an intranasal (i.n.) strategy for the treatment of pulmonary Francisella infection in mice that uses a combinatorial approach with the conventional antibiotic gentamicin and interleukin 12 (IL-12). The i.n. administration of IL-12 alone promoted bacterial clearance and extended the time to death but did not prevent mortality against lethal pulmonary challenge with Francisella tularensis subsp. novicida. However, i.n. treatment with gentamicin and IL-12 therapeutically at 8 and 24 h after challenge markedly enhanced the rate of survival (70 to 100%) against pulmonary infection compared to the rates of survival for animals treated with antibiotic alone (17%) or IL-12 alone (0%). A delay in combinatorial therapy over a span of 4 days progressively decreased the efficacy of this treatment regimen. This combinatorial treatment was shown to be highly dependent upon the induction of endogenous gamma interferon and may also involve the activation of natural killer cells. Together, these findings suggest that IL-12 may be a potent adjunct for chemotherapy to enhance drug effectiveness against pulmonary Francisella infection.