Recurrent Visceral Leishmaniasis in a Case With Interleukin-12 Receptor Beta-1 Deficiency.

PURPOSE: In this study, we present the case of a children who was followed up for recurrent visceral leishmaniasis and diagnosed with IL-12Rß1 deficiency. METHODS: A female patient who received Bacille Calmette-Guérin (BCG) vaccine 2 months after birth and developed visceral leishmaniasis at the age of 91 months was subsequently diagnosed with IL-12Rß1 deficiency. The patient's diagnosis and treatment process were examined retrospectively. RESULTS: IL-12Rß1 deficiency is an autosomal recessive disease characterized by susceptibility to recurrent and/or severe infections caused by weakly pathogenic mycobacteria and salmonella. Infections with other intramacrophagic organisms may also occur, although rarely. Based on this information, it is believed that the mutation in the IFN-γ/IL-12 axis in our patient predisposed her to recurrent Leishmania infections. CONCLUSION: This study adds to the limited literature on IL12RB1 deficiency as a cause of VL. Patients diagnosed with VL should be evaluated immunologically, as recurrent Leishmania infections may occur in those with IL-12Rß1 defects.

Differential expression of interleukin-35 receptor distinguishes different subsets of granulocyte-macrophage-colony-stimulating factor-producing T helper cells in a mouse endometriosis model.

The immune system contributes to the pathophysiology of endometriosis. The role of ThGM cells, which produce granulocyte macrophage-colony-stimulating factor (GM-CSF), in the pathogenesis of endometriosis remains unknown. To analyze the features of ThGM cells in endometriosis, a mouse endometriosis model was established. ThGM cells in the spleen, peritoneal fluid (PF), and endometriotic lesions (EL) were measured by flow cytometry, based on the expression of surface markers and intracellular proteins. Live ThGM cells were sorted according to chemokine receptor expression profiles and their effects on other CD4+ T cell subsets were determined by co-culture assays. An adoptive transfer assay was performed to characterize the effect of ThGM cells on endometriosis. We found that ThGM cells were present in endometriotic PF and EL. Live EL ThGM cells were enriched in CD4+CXCR3-CCR8-CCR4+CCR10+ T cells. EL ThGM cells differentially express interleukin-35 receptor (IL-35R), consisting of an IL-35R+ subset and an IL-35R- subset. The IL-35R+ subset expressed less GM-CSF, interleukin-2 (IL-2), and tumor necrosis factor-alpha (TNF-α) and proliferated slower than the IL-35R- subset. Meanwhile, the IL-35R+ subset was weaker than the IL-35R- subset in promoting the functions of Th1 and Th17 cells. ThGM cell transfer did not influence EL development but significantly alleviated pro-inflammatory cytokines in PF and ELs. Interleukin-35 (IL-35), the ligand of IL-35R, suppressed ThGM cell function and proliferation in an IL-35R-dependent manner. In summary, ThGM cells in the PF and ELs might exacerbate endometriotic inflammation. IL-35 might suppress the function of ThGM cells via IL-35R.

Association between gene polymorphisms of IL-12, IL-12 receptor and IL-27 and organ involvement in Iranian endometriosis patients.

Endometriosis is an inflammatory disease characterized by the presence of ectopic endometrial tissue, immune cell dysfunction and abnormal cytokine secretion. In addition to immunological factors, genetic variations that influence endometriosis severity and cytokine expression levels play important roles in the pathogenesis of this disease. Interleukin-12 (IL-12), specifically its p40 subunit encoded by IL-12B gene and the interleukin-12 receptor ß1 (IL-12Rß2) chain of its receptor, as well as interleukin-27 (IL-27) are important in the establishment of endometriosis. So, in this study, we measured IL-12 and IL-27 serum levels and investigated the possible links between IL-12B rs3212227, IL-12Rß2 rs3790565 and IL-27 rs153109 polymorphisms and the risk of developing endometriosis in a group of Iranian women. In this case-control study, 162 endometriosis patients and 151 healthy women were included and tested for the aforementioned polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The enzyme-linked immunosorbent assay (ELISA) method was also used to measure IL-12 and IL-27 serum levels. Although there was no statistically significant association between the genotypes and alleles of the studied polymorphisms and the development of endometriosis in general, the AA genotype of IL-12B rs3212227 showed a significant association with uterine endometriosis when compared to AC+CC genotypes (p = .04, CI = 0.270-0.988, OR = 0.517). Indeed, the AA genotype of the IL-12B rs3212227 single nucleotide polymorphism (SNP) may be linked with a lower risk of developing uterine endometriosis. There was no significant difference in IL-27 levels between the two studied groups (p = .49), and IL-12 levels were undetectable in both groups. In conclusion, the AA genotype of IL-12B rs3212227 might be associated with a decreased risk of uterine involvement in endometriosis patients.

IL-12RB1: a novel immune prognostic biomarker for oral squamous cell carcinoma and linked to PD-1/PD-L1 expression in the tumor immune microenvironment.

Background: This study aimed to screen and identify potential immune biomarker to predict the prognosis of oral squamous cell carcinoma (OSCC). Methods: Data of OSCC patient from The Cancer Genome Atlas (TCGA) database were downloaded, and the ESTIMATE algorithm was used to calculate stromal and immune scores. Differentially expressed genes (DEGs) between the high and low immune score groups were screened, and Kaplan-Meier survival analysis was performed to identify the DEGs linked to the overall survival (OS) time of OSCC patients. Then, those DEGs were validated in anther cohort. A correlation analysis was used to further screen the prognostic genes which were tightly linked to the expression of programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1). The expression profiles of the candidate genes interleukin 12 receptor subunit beta 1 (IL-12RB1), cytotoxic T-lymphocyte associated protein 4 (CTLA4), and G protein-coupled receptor 25 (GPR25) were identified in the single-cell RNA sequence OSCC dataset from GSE103322. Finally, immunohistochemistry (IHC) and immunofluorescence (IF) were applied to confirm the expression pattern of IL-12RB1 in OSCC tissue microarray. Kaplan-Meier analysis was used to assess the prognostic significance of IL-12RB1 staining score in the malignant and non-malignant cells among the patients. Results: The high immune score group showed better OS compared with that of the low immune scores group. Among 339 DEGs, 90 were identified as being tightly linked to OS time. In the validation set, 23 genes were confirmed to be closely associated with survival prognosis, and the expression levels of IL-12RB1, CTLA4, and GPR25 were commonly associated with the expression of PD-1/PD-L1. The RNA-sequencing showed that IL-12RB1 was expressed in epithelial and immune cells, whereas CTLA4 and GPR25 were relatively poorly expressed in the OSCC tissue. IHC showed that IL-12RB1 was positively expressed in both malignant and non-malignant cells. IF showed that IL-12RB1 was co-expressed with CD3, CD68, PD-1, and PD-L1 on the cytomembrane. Additionally, high score of IL-12RB1 expression in the non-malignant cells was a prognostic risk factor for OS of OSCC. Conclusions: IL-12RB1 was tightly associated with survival of OSCC and with the expression levels of PD-1/PD-L1 in the tumor immune microenvironment.

[The expression and significance of interleukin-35 receptor in oral lichen planus].

OBJECTIVE: To investigate the expression of glycoprotein 130 (gp130) and interleukin 12 receptor ß2 (IL-12Rß2) in two subunits of interleukin-35 receptor (IL-35R), singal transducer and activator of transcription (STAT) 1 and STAT4 in oral lichen planus (OLP) tissues, and to explore the role and significance of IL-35R in the formation and development of OLP lesions. METHODS: Totally 41 samples of OLP tissues (OLP group) and 15 samples of normal oral mucosa (control group) were collected. The expression levels of gp130, IL-12Rß2, STAT1, STAT4 mRNA in the tissues were detected by real-time fluorescent quantitative polymerase chain reaction and the distribution and expression of protein gp130 and IL-12Rß2 were detected by immunohistochemistry. The potential relationship between gp130 and IL-12Rß2 and clinical features of OLP was analyzed. RESULTS: 1) The expression levels of gp130, IL-12Rß2, STAT1 and STAT4 mRNA in the OLP group were significantly higher than those in the control group (P<0.05). 2) The positive expression rates of gp130 and IL-12Rß2 protein in the OLP group were higher than those in the control group (P<0.05). The expression of gp130 and IL-12Rß2 proteins in OLP tissues were positively correlated (r=0.984, P<0.001). 3) The expression rates of gp130 and IL-12Rß2 protein in erosive OLP tissues were significantly higher than those in non-erosive ones (P<0.05). CONCLUSIONS: The expression of IL-35R and STAT is up-regulated in OLP tissues, and the expression of IL-35R is related to the clinical classification of OLP, suggesting that IL-35R might play an important role in the formation and development of damage OLP lesions.

IL-12Rß1 deficiency corresponding to concurrency of two diseases, mendelian susceptibility to mycobacterial disease and Crohn's disease.

BACKGROUND: The interleukin-12 receptor ß1 (IL-12Rß1) deficiency is a primary immunodeficiency (PID), affecting the immunological pathway of interleukin 12/interferon- γ (IL12/IFN-γ) axis and interleukin 23 receptor (IL23R). Defect in this pathway is mainly affecting the cellular immunity-related disorders. IL-12Rß1 is a receptor chain of both the IL-12 and the IL-23 receptors and thus, deficiency of IL-12Rß1 abolishes both IL-12 and IL-23 signaling. MATERIAL AND METHODS: In this study, we performed whole exon sequencing and confirmatory Sanger sequencing in IL-12Rß1. Evaluation of the IL12/IFN-γ axis was performed by assessment of patients' whole blood cell to IL12/IFN-γ responding. Total and surface IL-12Rß1expression was evaluated, in peripheral blood mononuclear cells (PBMCs) and T cell- derived PBMCs, and Th17 count was assessed. RESULTS: In the present study, we described a c.1791 + 2T > G mutation at a splicing site position in IL-12Rß1, using whole exome sequencing, and confirmed with targeted Sanger sequencing in a 26- year-old patient with Mendelian susceptibility to mycobacterial disease (MSMD) and Crohn's disease (CD). Complete lack of IL-12Rß1 protein expression was detected in patient's PBMCs, compared to the healthy control. Furthermore, no IL-12Rß1 protein was expressed on the cell surface. Interestingly, IL-12Rß1-mutant cells showed an impaired response to IL12, and Bacillus Calmette-Guérin stimulation, confirming that the mutation is causative in this patient. CONCLUSION: A 3'splicing site mutation in IL12Rß1, can be corresponding to the abolished expression of IL12Rß1 in patients' cells, and associated with an impaired IL12-mediated signaling, which may lead not only to MSMD, but also to inflammatory bowel disease (IBD).

Current Status of the Management of Mendelian Susceptibility to Mycobacterial Disease in Mainland China.

PURPOSE: Although many studies have investigated Mendelian susceptibility to mycobacterial disease (MSMD) worldwide, there is no report of the long-term clinical management and prognosis for MSMD in China. METHODS: This is a cohort study from January 2000 to June 2018. Three hundred and twenty-four patients with bacillus Calmette-Guérin (BCG) infection were diagnosed during this period, and those with MSMD diagnosed by genetic and functional experiments were enrolled in the study. The clinical and genetic characteristics and management of these MSMD patients were summarized. RESULTS: Thirty patients diagnosed with MSMD were followed up. The age at the follow-up end point ranged from 5 to 173 months. Among the patients, IL12RB1 mutations were identified in 22, IFNGR1 mutations in 5, STAT1 mutations in 2, and IFNGR2 mutation in 1. The medium age at onset was 3 months. BCG infection involved multiple organs, including regional infection (8/30; 26.7%) or distant or disseminated infection (22/30; 73.3%). Ten percent (30/324) of patients with BCG infection had a confirmed MSMD diagnosis. Protein expression of IL12RB1 or IFNGR1 was decreased in all patients with IL12RB1 or IFNGR1 mutation, respectively, as indicated by flow cytometry. In addition, 77.8% of patients received rhIFN-γ treatment, which can improve the prognosis of patients with IL12RB1 deficiency. Two patients received stem cell transplantation. Twenty-five patients remained alive at the time of publication. CONCLUSION: MSMD is an important cause of BCG infection. Flow cytometric detection of IL12RB1 and IFNGR1 expression is very useful for rapid MSMD diagnosis. rhIFN-γ therapy is effective in patients with MSMD, particularly improving prognosis in those with IL12RB1 deficiency.

Autoantibodies in patients with interleukin 12 receptor beta 1 deficiency.

OBJECTIVE: Interleukin 12 receptor beta 1 (IL-12Rß1) deficiency is a primary immunodeficiency that exposes affected individuals to an augmented risk of intracellular pathogen-mediated infections. The paradoxical presence of autoimmune manifestations in immune-deficient patients has been recognized, but the basis of this phenomenon is unclear, with the role of frequent infections being a possible trigger to break tolerance. Our study aimed to analyze extensively a profile of autoantibodies in a clinically well-defined case series of patients with IL-12Rß1 deficiency. METHODS: Eight patients with IL-12Rß1 deficiency referred to Children's Medical Center in Tunis, Tunisia, during 1995-2012 were enrolled in the study. Sixteen age- and gender-matched blood donors served as controls. Serum, liver-related autoantibodies immunoglobulin (Ig)G, IgM, IgA were tested by ELISA and by standard indirect immunofluorescence on Hep-2 cells. RESULTS: We found a significant prevalence of liver autoantibodies in the study group. Regarding primary biliary cholangitis (PBC), two of eight patients were positive for MIT3 autoantibodies, both confirmed by immunofluorescence, and one patient was positive for PBC-specific antinuclear antibodies, sp100. Moreover, two patients had significantly increased gamma-glutamyltransferase levels and one had IgM levels twice the upper limit of normal. Intriguingly two patients were positive for anti-actin antibodies; a typical feature of autoimmune hepatitis type 1, along with a significant increase in IgG levels. CONCLUSIONS: This is the first report of a serological analysis in patients with an IL-12Rß1 deficiency. Despite the difficulty in interpreting the role of the IL-12, the evidence of liver-specific autoantibodies confirms the importance its signal in liver autoimmunity.

Interleukin-12 receptor ß2 from grass carp: Molecular characterization and its involvement in Aeromonas hydrophila-induced intestinal inflammation.

Interleukin-12 receptor ß2 (IL-12Rß2) is a signaling subunit of heterodimeric receptors for IL-12 and IL-35. It plays important regulatory functions in the development of Th1 cells and in the expression of inflammatory cytokines in mammals and other higher vertebrates. However, little is known about IL-12Rß2 in teleost fish. In this work, we have cloned and characterized IL-12Rß2 from grass carp (Ctenopharyngodon idella). The full-length cDNA of grass carp IL-12Rß2 is 2875 bp, which encodes a mature protein with 741 amino acids. This mature protein contains three fibronectin type III domains, a transmembrane helix, and CXW and WSXWS-like motifs that are characteristic of the type I cytokine receptor family. Phylogenetic analysis revealed that cyprinid fish IL-12Rß2 formed a single branch, clearly separated from those of other vertebrates. We expressed and purified a recombinant grass carp IL-12Rß2 protein containing major antigenic regions, which was used to raise a polyclonal antibody. The specificity of the antibody was assessed by Western blotting analysis of whole cell lysates from Escherichia coli cells expressing the recombinant IL-12Rß2, grass carp intestinal intraepithelial lymphocytes, and cultured C. idella kidney cells. To explore the potential regulatory role of IL-12Rß2 in inflammation, we generated an intestinal inflammation model by anal intubation of fish with Aeromonas hydrophila. Immunohistochemical staining of the inflamed intestines revealed that IL-12Rß2 expression is consistent with inflammatory cell recruitment during intestinal inflammation. Real-time quantitative PCR revealed that IL-12Rß2 is widely expressed in normal tissues and is up-regulated in most tissues after infecting with A. hydrophila. We found that IL-12Rß2, IL-12p35, and interferon-γ were expressed in similar patterns in the intestines during inflammation. Taken together, our results suggest that IL-12Rß2 is involved in the regulation of intestinal inflammation.

MiR-151a is involved in the pathogenesis of atopic dermatitis by regulating interleukin-12 receptor ß2.

MicroRNAs (miRNAs) have been reported to circulate in the blood in a highly stable and cell-free form. Dysregulated expression of miRNAs has been detected in various pathological conditions including atopic dermatitis. In our study, human blood plasma miRNAs were identified by high-throughput sequencing and compared among patients of atopic dermatitis and healthy controls. We found that miR-151a was differentially expressed in the plasma of atopic dermatitis patients. MiR-151a regulates the expression of IL12RB2 by targeting two loci in the 3' untranslated region of the Il12rb2 gene. Moreover, IL12RB2 was remarkably downregulated in Jurkat cells overexpressing miR-151a. Jurkat cells treated with phytohemagglutinin also showed reduced expression of IFN-γ, interleukin-2 (IL-2) and IL-12. Together, these results suggest that miR-151a is involved in the pathogenesis of atopic dermatitis by regulating IL12RB2.

A high ratio of IL-12Rß2-positive tumor-infiltrating lymphocytes indicates favorable prognosis in laryngeal cancer.

BACKGROUND: The purpose of this study was to elucidate IL-12Rß2's roles as a tumor-associated immunological molecule, delineate the complex roles of IL-12Rß2+ tumor-infiltrating lymphocytes (TILs) and tumor cell IL-12Rß2 expression in the tumor microenvironment, and determine the correlation of IL-12Rß2+ TILs and tumor cell IL-12Rß2 expression with clinical prognosis. METHODS: We assessed mRNA and protein levels in matched laryngeal cancer tissues (LTs) and adjacent normal mucous membrane tissues (ANMMTs) from 3 laryngeal cancer (LC) patients and ratios of IL-12Rß2+ TILs in matched LTs and ANMMTs from 61 LC patients. We used the Kaplan-Meier log-rank test and Cox regression hazard ratios to analyze survival. RESULTS: Comparative proteomic and transcriptomic assays revealed that matched LTs and ANMMTs from the 3 patients had significantly different IL-12Rß2 and IFN-γ expression; the ratio of IL-12Rß2+ TILs decreased with lower degrees of tumor differentiation. Among all 61 LC patients, the IL-12Rß2+ TIL ratio in ANMMTs (38.5% ±â€¯22.8%) was significantly higher than that in LTs (29.7% ±â€¯19%; p<.001). Kaplan-Meier analysis revealed that patients with an IL-12Rß2+ TIL ratio ≥35% had significantly better survival than those with an IL-12Rß2+ TIL ratio <35% (log rank p=0.041). Multivariable analysis showed a significant association between a high IL-12Rß2+ TIL ratio and overall survival (hazard ratio, 0.14; 95% confidence interval, 0.03-0.77). CONCLUSION: Tumor cell differentiation is associated with TILs' expression of IL-12Rß2, and an IL-12Rß2+ TIL ratio ≥35%) indicates favorable prognosis in LC.

First Association of Interleukin 12 Receptor Beta 1 Deficiency with Sjögren's Syndrome.

INTRODUCTION: Interleukin 12 receptor beta 1 (IL12Rß1) deficiency is a primary immunodeficiency resulting mainly in susceptibility to opportunistic infection by non-tuberculous, environmental mycobacteria and severe infection caused by Salmonella spp. Till now, less than 300 patients with IL12Rß1 deficiency have been reported. Among them, only three have been described to develop autoimmunity. CASE PRESENTATION: We present the case of a 50-year-old male with IL12Rß1 deficiency due to compound heterozygosity [c. 1623_1624delGCinsTT (pGln542Stop) and c.1791 + 2T > C (donor splice site)], who-18 months after diagnosis of disseminated BCGitis-presented with recurrent fever and sicca syndrome. No indication of an infectious origin of these symptoms could be found at that point. The diagnosis of a Sjögren's syndrome (SS) was made on the basis of fulfilled American-European consensus classification criteria, including a positive minor salivary gland biopsy. CONCLUSION: Apart from persistent antigenic stimulation, which may drive autoimmune inflammation in primary immunodeficiency, evidence on the involvement of interleukin 12 in pathogenesis of SS suggests that the same immunological mechanism may underlie both defense against infection and the maintenance of tolerance. To our knowledge, this is the first report of a case of autoimmunity in the form of SS in a patient with a primary immunodeficiency and one of the rare cases of IL12Rß1 deficiency with manifested autoimmunity.

IL-12 receptor 1ß deficiency with features of autoimmunity and photosensitivity.

Primary immunodeficiences are often accompanied by autoimmune phenomena. IL-12 receptor deficiency is a well characterized primary immunodeficiency that leads to propensity to intracellular infections mainly with mycobacteria and Salmonella. We report on two patients with IL-12 receptor ß1 deficiency that presented with autoimmune manifestations and photosensitivity dermatitis and describe possible pathogenetic mechanisms leading to development of clinically significant autoimmune phenomena.

Functional analysis of differences in transcriptional activity conferred by genetic variants in the 5' flanking region of the IL12RB2 gene.

Interleukin 12 receptor ß chain (IL12RB2) is a crucial regulatory factor involved in cell-mediated immune responses, and genetic variants of the gene encoding IL12RB2 are associated with susceptibility to various immune-related diseases. We previously demonstrated that haplotypes with single nucleotide polymorphisms (SNPs) in the 5' flanking region of IL12RB2, including -1035A>G (rs3762315) and -1023A>G (rs3762316), affect the expression of IL12RB2, thereby altering susceptibility to leprosy and periodontal diseases. In the present study, we identified transcription factors associated with the haplotype-specific transcriptional activity of IL12RB2 in T cells and NK cells. The -1023G polymorphism was found to create a consensus binding site for the transcription factor activating protein (AP)-1, and enzyme-linked immunosorbent assay (ELISA)-based binding assays showed that these SNPs enhanced AP-1 binding to this region. In reporter assays, suppression of JunB expression using siRNA eliminated differences in the -1035G/-1023G and -1035A/-1023A regions containing IL12RB2 promoter activity in Jurkat T cells and NK3.3 cells. These results suggested that the -1035/-1023 polymorphisms created differential binding affinities for JunB that could lead to differential IL12RB2 expression. Moreover, the -1035G and -1035A alleles formed binding sites for GATA-3 and myocyte enhancer factor-2 (MEF-2), respectively. Our data indicated that in addition to JunB, the SNP at -1035/-1023 influenced GATA-3 and MEF-2 binding affinity, potentially altering IL12RB2 transcriptional activity. These findings confirm the effects of rs3762315 and rs3762316 on IL12RB2 transcription. These genetic variants may alter cellular activation of T cells and NK cells and modify cell-mediated immune responses.

Higher expression of IL-12Rß2 is associated with lower risk of relapse in relapsing-remitting multiple sclerosis patients on interferon-ß1b therapy during 3-year follow-up.

Cytokines produced by helper T (Th)1 cells, Th17 and regulatory T cells (Treg) are involved in multiple sclerosis (MS) immunopathogenesis. Interferon (IFN)-ß alters the numerous genes' expression, but how this alteration affects the treatment response is still elusive. We assessed relative gene expression of nineteen Th1/Th17/Treg-associated mediators in peripheral blood mononuclear cells and plasma levels of GM-CSF, IL-17A and IL-17F, in relapsing-remitting MS (RRMS) patients before IFN-ß1b treatment initiation and at 6, 12, 24 and 36 months of therapy. All mRNA levels changed significantly during the IFN-ß1b therapy. Higher IL-12Rß2 mRNA levels were associated with lower risk of relapse. Despite recent reports regarding role of GM-CSF in MS, our study failed to demonstrate its significance as therapy response biomarker, both on the mRNA and protein level.

Disseminated BCG in an infant with interleukin-12 receptor B1 (IL12RB1) deficiency.

Although neonatal vaccination with bacille Calmette-Guérin (BCG) is considered to be safe, complications with disseminated disease are associated with underlying immuno-deficiency disorders. A BCG-vaccinated 4-month-old girl of Sri Lankan parentage developed progressive left axillary lymphadenopathy and severe bronchopneumonia. Lymph node biopsy demonstrated epithelioid granulomata and acid-fast bacilli. An older sibling had had a similar clinical presentation and the outcome had been fatal. Investigation for immuno-deficiency detected complete IL12RB1 deficiency. Full recovery followed a prolonged course of anti-tuberculous chemotherapy. She was put on lifelong isoniazid prophylaxis. In HIV-negative infants with unusual complications related to BCG vaccination, a primary immuno-deficiency disorder should be considered.

Non-canonical interleukin 23 receptor complex assembly: p40 protein recruits interleukin 12 receptor ß1 via site II and induces p19/interleukin 23 receptor interaction via site III.

IL-23, composed of the cytokine subunit p19 and the soluble α receptor subunit p40, binds to a receptor complex consisting of the IL-23 receptor (IL-23R) and the IL-12 receptor ß1 (IL-12Rß1). Complex formation was hypothesized to follow the "site I-II-III" architectural paradigm, with site I of p19 being required for binding to p40, whereas sites II and III of p19 mediate binding to IL-12Rß1 and IL-23R, respectively. Here we show that the binding mode of p19 to p40 and of p19 to IL-23R follow the canonical site I and III paradigm but that interaction of IL-23 to IL-12Rß1 is independent of site II in p19. Instead, binding of IL-23 to the cytokine binding module of IL-12Rß1 is mediated by domains 1 and 2 of p40 via corresponding site II amino acids of IL-12Rß1. Moreover, domains 2 and 3 of p40 were sufficient for complex formation with p19 and to induce binding of p19 to IL-23R. The Fc-tagged fusion protein of p40_D2D3/p19 did, however, not act as a competitive IL-23 antagonist but, at higher concentrations, induced proliferation via IL-23R but independent of IL-12Rß1. On the basis of our experimental validation, we propose a non-canonical topology of the IL-23·IL-23R·IL-12Rß1 complex. Furthermore, our data help to explain why p40 is an antagonist of IL-23 and IL-12 signaling and show that site II of p19 is dispensable for IL-23 signaling.

Molecular analysis for patients with IL-12 receptor ß1 deficiency.

Autosomal recessive interleukin-12 receptor ß1 (IL-12Rß1) deficiency has been described as the most common cause of Mendelian susceptibility to mycobacterial disease (MSMD), characterized by clinical disease due to weakly virulent mycobacteria such as Bacille Calmette-Guérin (BCG) vaccines and environmental mycobacteria (EM) in children who are normally resistant to most infectious agents. Here, we report the cases of five patients with mycobacterial infection, including one with systemic lupus erythematosus (SLE). Blood samples from patients and healthy controls were activated in vitro with BCG, BCG+IL-12, and BCG+IFN-γ. The results showed reduced or no production of IFN-γ after IL-12 stimulation in all samples. IL-12Rß1 expression on the cell surface was negligible or absent. Genetic analysis showed five novel mutations.

Interleukin-12 (IL-12), but not IL-23, induces the expression of IL-7 in microglia and macrophages: implications for multiple sclerosis.

Interleukin-12 (IL-12) p70 and IL-23 are bioactive cytokines and their biological functions are becoming clear. Increased expression of IL-7 in the central nervous system as well as in peripheral immune cells is associated with multiple sclerosis and experimental allergic encephalomyelitis. Here, we describe the induction of IL-7 in primary mouse and human microglia, BV-2 microglial cells, mouse peritoneal macrophages and astrocytes by IL-12p70. Interestingly, IL-12 strongly induced the expression of IL-7 whereas IL-23 and other p40 family members remained weak inducers of IL-7 in these cell types. Consistently, IL-12, but not IL-23 and other p40 family members, induced IL-7 promoter-driven luciferase activity in microglial cells. Among various stimuli tested, IL-12 emerged as the most potent stimulus followed by bacterial lipopolysaccharide and HIV-1 gp120 in inducing the activation of IL-7 promoter in microglial cells. Furthermore, increase in IL-7 mRNA expression by over-expression of IL-12p35 subunit, but not p40 and IL-23 p19 subunit, confirm that p35, but not p40 and p19, is responsible for the induction of IL-7. Finally, by using primary microglia from IL-12 receptor ß1-deficient (IL-12Rß1(-/-)) and IL-12Rß2(-/-) mice, we demonstrate that IL-12 induces the expression of IL-7 in microglia and macrophages via both IL-12Rß2 and IL-12Rß1. These studies delineate a novel biological function of IL-12 that is absent in IL-23 and other p40 family members.