A Germinal Center Checkpoint of AIRE in B Cells Limits Antibody Diversification.

In response to antigens, B cells undergo affinity maturation and class switching mediated by activation-induced cytidine deaminase (AID) in germinal centers (GCs) of secondary lymphoid organs, but uncontrolled AID activity can precipitate autoimmunity and cancer. The regulation of GC antibody diversification is of fundamental importance but not well understood. We found that autoimmune regulator (AIRE), the molecule essential for T cell tolerance, is expressed in GC B cells in a CD40-dependent manner, interacts with AID and negatively regulates antibody affinity maturation and class switching by inhibiting AID function. AIRE deficiency in B cells caused altered antibody repertoire, increased somatic hypermutations, elevated autoantibodies to T helper 17 effector cytokines and defective control of skin Candida albicans. These results define a GC B cell checkpoint of humoral immunity and illuminate new approaches of generating high-affinity neutralizing antibodies for immunotherapy.

IL-6-specific autoantibodies among APECED and thymoma patients.

INTRODUCTION: Both autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) and the rare thymoma patients with chronic mucocutaneous candidiasis (CMC) have neutralizing autoantibodies to Th17 cytokines and significant defects in production of IL-22 and IL-17F by their T cells. The cause of these defects is unknown. We hypothesized that they might result from autoimmunity against upstream cytokines normally responsible for generating and maintaining Th17 cells. METHODS: Luciferase immunoprecipitation (LIPS) was used to screen for autoantibodies to IL-6, IL-1ß, TGF-ß3, IL-21, and IL-23 in patients with APECED or thymoma. We used Western blotting to assess the conformation-dependence of the IL-6 autoantibodies and flow cytometric analysis of intracellular phospho-STAT3 induction to assess IL-6-neutralizing capacity in IgGs isolated from patient and control sera. We also used Luminex xMAP to measure serum cytokine levels. RESULTS: We found autoantibodies binding to conformational epitopes of IL-6 in 19.5% of 41 patients with APECED and 12.5% of 104 with thymoma-especially in those with long disease durations. The autoantibodies were predominantly of IgG1 subclass and failed to neutralize IL-6 activity. Notably, serum levels of the IL-6 and IL-17A cytokines were higher in anti-IL-6 seropositive than-negative APECED patients or healthy controls. We also detected autoantibody binding to IL-23 in 27.9% of thymoma patients, resulting from cross-recognition through the p40 subunit it shares with IL-12. CONCLUSIONS: IL-6 and IL-17A elevation in these seropositive patients suggests that antibody-binding may protect IL-6 from degradation and prolong its half-life in vivo.

Gastrointestinal Autoimmunity Associated With Loss of Central Tolerance to Enteric α-Defensins.

BACKGROUND & AIMS: Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is an autoimmune disorder characterized by chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal insufficiency, but patients also develop intestinal disorders. APECED is an autosomal recessive disorder caused by mutations in the autoimmune regulator (AIRE, which regulates immune tolerance) that allow self-reactive T cells to enter the periphery. Enteric α-defensins are antimicrobial peptides secreted by Paneth cells. Patients with APECED frequently have gastrointestinal symptoms and seroreactivity against secretory granules of Paneth cells. We investigated whether enteric α-defensins are autoantigens in humans and mice with AIRE deficiency. METHODS: We analyzed clinical data, along with serum and stool samples and available duodenal biopsies from 50 patients with APECED collected from multiple centers in Europe. Samples were assessed for expression of defensins and other molecules by quantitative reverse transcription polymerase chain reaction and flow cytometry; levels of antibodies and other proteins were measured by immunohistochemical and immunoblot analyses. Histologic analyses were performed on biopsy samples. We used Aire(-/-) mice as a model of APECED, and studied the effects of transferring immune cells from these mice to athymic mice. RESULTS: Enteric defensins were detected in extraintestinal tissues of patients with APECED, especially in medullary thymic epithelial cells. Some patients with APECED lacked Paneth cells and were seropositive for defensin-specific autoantibodies; the presence of autoantibodies correlated with frequent diarrhea. Aire(-/-) mice developed defensin-specific T cells. Adoptive transfer of these T cells to athymic mice resulted in T-cell infiltration of the gut, loss of Paneth cells, microbial dysbiosis, and the induction of T-helper 17 cell-mediated autoimmune responses resembling those observed in patients with APECED. CONCLUSIONS: In patients with APECED, loss of AIRE appears to cause an autoimmune response against enteric defensins and loss of Paneth cells. Aire(-/-) mice developed defensin-specific T cells that cause intestinal defects similar to those observed in patients with APECED. These findings provide a mechanism by which loss of AIRE-mediated immune tolerance leads to intestinal disorders in patients with APECED.

Neuron navigator 3 alterations in nervous system tumors associate with tumor malignancy grade and prognosis.

Copy number changes or reduced expression of the Neuron navigator 3 (NAV3) gene occurs in neuroblastomas and malignancies of epithelial or lymphoid origin. To elucidate whether NAV3 has a role in the tumorigenesis of nervous system tumors in general, we studied central and peripheral nervous system tumors for NAV3 copy number changes. In search for common tumorigenic denominators, we analyzed 113 central and peripheral nervous system tumors, including glial tumors (grades I-IV gliomas), medulloblastomas, and neuroblastomas. NAV3 copy number changes were studied by fluorescence in situ hybridization and correlated to survival analyses. To identify target genes of NAV3 deletion, NAV3 was silenced by siRNA in glioblastoma cell lines and gene expression profiles were analyzed by Agilent 4×44k dual-color microarrays. Selected upregulations were confirmed by immunohistochemistry and quantitative polymerase chain reaction. We found NAV3 amplifications to dominate in neuronally differentiated tumors, whereas glial tumors showed almost equal proportions of NAV3 deletion and amplification. However, Grade IV gliomas had more frequent NAV3 deletions than grades I-III gliomas. Silencing of NAV3 in glioma cell lines led to the upregulation of receptor genes associated with gonadotropin-releasing hormone and Jak-Stat signaling pathways. Kaplan-Meier analysis of the entire clinical tumor material showed association between NAV3 amplifications and favorable prognosis, as well as NAV3 deletions and unfavorable prognosis. With Cox regression model, a hazard ratio of 0.51 was observed for NAV3 amplifications and 1.36 for NAV3 deletions. We conclude that NAV3 may be a potential new prognostic biomarker and a potential therapeutic target.

What is the burden of living with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) in 2012? A health-related quality-of-life assessment in Finnish patients.

OBJECTIVE: Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is a rare disorder responsible for chronic candidiasis, a wide variety of autoimmune disorders and a risk of squamous cell carcinoma of the oral cavity or oesophagus. We investigated the impairment of quality of life in our cohort of Finnish patients. SUBJECTS, DESIGN AND MEASUREMENT: In a postal survey, 26 patients with APECED responded to three self-reported health-related quality-of-life questionnaires: RAND-36 (general health), RBDI (depression) and DLQI (dermatology life quality index). RESULTS: General health and vitality were the most affected items in our cohort. Male subjects presented higher impairment in emotional role limitations, social functioning, bodily pain, general mental health/emotional well-being, energy/vitality and general health perceptions but without reaching statistical significance. The number of accumulated diseases in APECED was not associated with lower results. But, age and duration of APECED correlated with fatigue (P = 0·01), well-being (P = 0·02) and general health (P = 0·03) impairment. Depressive symptoms affected 29% of the patients. There was a statistical negative correlation between RBDI score and age and duration of APECED. Hair loss, alopecia areata universalis especially, affected more severely the quality of life of female patients. Vitiligo and candidiasis did not have any significant impact on both the genders. CONCLUSIONS: We report the first study on specific impairment of quality of life related to APECED in a cohort of adult Finnish patients. General health, emotional well-being and vitality were the most diminished aspects of quality of life in our cohort. However, our results will need to be confirmed by additional controlled studies.

Molecular markers associated with clinical response to bexarotene therapy in cutaneous T-cell lymphoma.

Bexarotene (Targretin(®)), was registered for the treatment of cutaneous T-cell lymphoma (CTCL) in 2002, and has been reported to induce a 45% overall response. Responses are mostly partial or generate a stable, skin-restricted disease. This study explored the usefulness of a novel cancer-associated gene, NAV3 and corresponding chromosome 12 copy numbers as possible biomarkers to monitor the therapeutic response to bexarotene in 21 Finnish patients with CTCL. Six patients (29%) reached complete remission (CR) and 3 of these remained in CR for more than 24 months, 12 (57%) reached a partial response (PR, with one stable disease) and 3 were non-responders. Low-level NAV3 deletions were detected using a fluorescence in-situ hybridization (FISH) assay in the lesions of 5 patients, 4 of whom were non-responders or progressed after short PR. This occurrence of NAV3 deletions was statistically significant compared with non-progressors (p = 0.011, Fisher's exact test). Chromosome 12 tetraploidy was found in the lesions of two of the 3 patients with CR who remained in remission. While such tetraploidy is a feature of proliferating normal T cells, this observation may reflect a favourable anti-tumour immune response among the skin-infiltrating lymphocytes.

Chronic mucocutaneous candidiasis in APECED or thymoma patients correlates with autoimmunity to Th17-associated cytokines.

Chronic mucocutaneous candidiasis (CMC) is frequently associated with T cell immunodeficiencies. Specifically, the proinflammatory IL-17A-producing Th17 subset is implicated in protection against fungi at epithelial surfaces. In autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED, or autoimmune polyendocrine syndrome 1), CMC is often the first sign, but the underlying immunodeficiency is a long-standing puzzle. In contrast, the subsequent endocrine features are clearly autoimmune, resulting from defects in thymic self-tolerance induction caused by mutations in the autoimmune regulator (AIRE). We report severely reduced IL-17F and IL-22 responses to both Candida albicans antigens and polyclonal stimulation in APECED patients with CMC. Surprisingly, these reductions are strongly associated with neutralizing autoantibodies to IL-17F and IL-22, whereas responses were normal and autoantibodies infrequent in APECED patients without CMC. Our multicenter survey revealed neutralizing autoantibodies against IL-17A (41%), IL-17F (75%), and/ or IL-22 (91%) in >150 APECED patients, especially those with CMC. We independently found autoantibodies against these Th17-produced cytokines in rare thymoma patients with CMC. The autoantibodies preceded the CMC in all informative cases. We conclude that IL-22 and IL-17F are key natural defenders against CMC and that the immunodeficiency underlying CMC in both patient groups has an autoimmune basis.

Mapping of human autoantibody binding sites on the calcium-sensing receptor.

Previously, we have demonstrated the presence of anti-calcium-sensing receptor (CaSR) antibodies in patients with autoimmune polyglandular syndrome type 1 (APS1), a disease that is characterized in part by hypoparathyroidism involving hypocalcemia, hyperphosphatemia, and low serum levels of parathyroid hormone. The aim of this study was to define the binding domains on the CaSR of anti-CaSR antibodies found in APS1 patients and in one patient suspected of having autoimmune hypocalciuric hypercalcemia (AHH). A phage-display library of CaSR peptides was constructed and used in biopanning experiments with patient sera. Selectively enriched IgG-binding peptides were identified by DNA sequencing, and subsequently, immunoreactivity to these peptides was confirmed in ELISA. Anti-CaSR antibody binding sites were mapped to amino acid residues 41-69, 114-126, and 171-195 at the N-terminal of the extracellular domain of the receptor. The major autoepitope was localized in the 41-69 amino acid sequence of the CaSR with antibody reactivity demonstrated in 12 of 12 (100%) APS1 patients with anti-CaSR antibodies and in 1 AHH patient with anti-CaSR antibodies. Minor epitopes were located in the 114-126 and 171-195 amino acid domains, with antibody reactivity shown in 5 of 12 (42%) and 4 of 12 (33%) APS1 patients, respectively. The results indicate that epitopes for anti-CaSR antibodies in the AHH patient and in the APS1 patients who were studied are localized in the N-terminal of the extracellular domain of the receptor. The present work has demonstrated the successful use of phage-display technology in the discovery of CaSR-specific epitopes targeted by human anti-CaSR antibodies.

Combining DNA technologies and different modes of immunization for induction of humoral and cellular anti-HIV-1 immune responses.

We show here that it is possible to combine two different genetic immunogens, one designed to induce HIV-1 specific humoral immune responses (pKCMVgp160B) and one designed to induce cellular anti-HIV-1 immune responses (Auxo-GTU-MultiHIV), and still retain the major properties of both vaccine constructs. The two different constructs were delivered using two different methods; the gene-gun and the Biojector, which both are needle-free devices. In BALB/c mice we were able to induce high levels of HIV-1-specific T cell responses as well as high levels of anti-gp160 antibodies by co-administrating the vaccine constructs. The cellular immune responses, but not antibody responses, were moderately compromised from the combination. This study shows that it is a feasible strategy to combine different vaccines and modes of delivery, but that interference as to magnitude may occur to certain gene products.

GTU-MultiHIV DNA vaccine results in protection in a novel P815 tumor challenge model.

A novel animal model for testing the immunogenicity and protective immune response induced by HIV-1 DNA vaccines was developed. DBA/2 mice were immunized with GTU-MultiHIV DNA encoding multigene for Rev, Nef, Tat, optp17/24 and a stretch of Pol/Env epitopes. A single GTU-MultiHIV B-clade specific plasmid or Auxo-GTU-MultiHIV(mix) (mixture of four plasmids with A, B, C and FGH clade specific MultiHIV antigens) were administered via gene gun and cell-mediated and humoral immune responses were analysed. The protective efficacy of the immune response was evaluated by challenging the mice with syngeneic tumor cells (P815) stably transfected with the MultiHIV fusion gene. Our results show that the strong MultiHIV-specific immune response generated by the GTU-MultiHIV vaccines in DBA/2 mice was able to delay the tumor growth substantially, indicating that the CTL response detected in vitro confers protection in vivo. The model described here is a safe and feasible in vivo assay for assessment of the vaccine potency to induce protective cell-mediated immune responses.

Induction of human immunodeficiency virus type-1-specific immunity with a novel gene transport unit (GTU)-MultiHIV DNA vaccine.

A multiHIV fusion gene expressing an antigenic fusion protein composed of regulatory HIV-1 proteins Rev, Nef, and Tat, as well as Gag p17/p24 and a stretch of 11 cytotoxic T lymphocyte (CTL) epitope clusters from Pol and Env, was cloned into a novel DNA vector named the Gene Transport Unit (GTU). A mouse H-2(d)-restricted HIV-1 gp120 epitope (RGPGRAFVTI) was cloned into the fusion gene as well. In addition to the HIV- 1 genes the GTU codes for a nuclear anchoring protein (bovine papilloma virus E2), ensuring the long maintenance of the vector and a high expression level of the selected immunogens. BALB/c mice were immunized with the GTU-MultiHIV DNA construct by different routes and regimens of immunization to assess the immunogenicity of the DNA vaccine in vivo. Mice developed strong CD8(+) CTL responses to HIV-1 Env and Gag measured by an ELISPOT-IFN-gamma assay and chromium release assay. In addition, T cell responses to regulatory proteins Rev, Nef, and Tat were induced. Antibody responses were detected to each of the HIV antigens encoded by the DNA construct. Minimal doses of the GTU-MultiHIV DNA delivered by gene gun were potent in inducing significant HIV-specific CTL responses. The equivalent doses of the conventional plasmid expressing MultiHIV DNA delivered by gene gun failed to do so. An ideal DNA vaccine should yield high expression of the viral antigens for a prolonged period of time, and expression of the multiple viral antigens is probably required for the induction of a broad and protective immune response. The GTU-MultiHIV DNA vaccine described is a good vaccine candidate that meets the above criteria.

Anti-interferon autoantibodies in autoimmune polyendocrinopathy syndrome type 1.

BACKGROUND: The autoimmune regulator (AIRE) gene influences thymic self-tolerance induction. In autoimmune polyendocrinopathy syndrome type 1 (APS1; OMIM 240300), recessive AIRE mutations lead to autoimmunity targetting endocrine and other epithelial tissues, although chronic candidiasis usually appears first. Autoimmunity and chronic candidiasis can associate with thymomas as well. Patients with these tumours frequently also have high titre immunoglobulin G autoantibodies neutralising type I interferon (IFN)-alpha and IFN-omega, which are secreted signalling proteins of the cytokine superfamily involved in both innate and adaptive immunity. METHODS AND FINDINGS: We tested for serum autoantibodies to type I IFNs and other immunoregulatory cytokines using specific binding and neutralisation assays. Unexpectedly, in 60/60 Finnish and 16/16 Norwegian APS1 patients with both AIRE alleles mutated, we found high titre neutralising immunoglobulin G autoantibodies to most IFN-alpha subtypes and especially IFN-omega (60% homologous to IFN-alpha)-mostly in the earliest samples. We found lower titres against IFN-beta (30% homologous to IFN-alpha) in 23% of patients; two-thirds of these (from Finland only) also had low titres against the distantly related "type III IFN" (IFN-lambda1; alias interleukin-29). However, autoantibodies to the unrelated type II IFN, IFN-gamma, and other immunoregulatory cytokines, such as interleukin-10 and interleukin-12, were much rarer and did not neutralise. Neutralising titres against type I IFNs averaged even higher in patients with APS1 than in patients with thymomas. Anti-type I IFN autoantibodies preceded overt candidiasis (and several of the autoimmune disorders) in the informative patients, and persisted for decades thereafter. They were undetectable in unaffected heterozygous relatives of APS1 probands (except for low titres against IFN-lambda1), in APS2 patients, and in isolated cases of the endocrine diseases most typical of APS1, so they appear to be APS1-specific. Looking for potentially autoimmunising cell types, we found numerous IFN-alpha(+) antigen-presenting cells-plus strong evidence of local IFN secretion-in the normal thymic medulla (where AIRE expression is strongest), and also in normal germinal centres, where it could perpetuate these autoantibody responses once initiated. IFN-alpha2 and IFN-alpha8 transcripts were also more abundant in antigen-presenting cells cultured from an APS1 patient's blood than from age-matched healthy controls. CONCLUSIONS: These apparently spontaneous autoantibody responses to IFNs, particularly IFN-alpha and IFN-omega, segregate like a recessive trait; their high "penetrance" is especially remarkable for such a variable condition. Their apparent restriction to APS1 patients implies practical value in the clinic, e.g., in diagnosing unusual or prodromal AIRE-mutant patients with only single components of APS1, and possibly in prognosis if they prove to predict its onset. These autoantibody responses also raise numerous questions, e.g., about the rarity of other infections in APS1. Moreover, there must also be clues to autoimmunising mechanisms/cell types in the hierarchy of preferences for IFN-omega, IFN-alpha8, IFN-alpha2, and IFN-beta and IFN-lambda1.

Cross-clade protection induced by human immunodeficiency virus-1 DNA immunogens expressing consensus sequences of multiple genes and epitopes from subtypes A, B, C, and FGH.

The correlate of protection in human immunodeficiency virus (HIV) infection is not known, but preclinical and clinical studies support the involvement of both antibodies and cellular immunity. In addition, the existence of multiple HIV clades makes HIV vaccine design especially challenging. We have constructed a vaccine platform with an HIV-1 subtype B DNA immunogen expressing full length consensus sequences from HIV-1 rev, nef, tat, and gag with additional cellular epitope clusters from the env and pol regions. Furthermore, this platform has been extended to three additional plasmids expressing the same immunogens but originating from subtypes A or C consensus or FGH ancestral sequences. Immunogenicity in BALB/c mice, by gene gun or intramuscular delivery, revealed strong IFN-gamma production in response to in vitro re-stimulation with a H-2d restricted gag peptide (AMQMLKETI) or even stronger toward an env epitope (RGPGRAFVTI). Weak humoral immunity was detected. Gene gun immunization with a cocktail of all four plasmids induced pre-challenge cellular immunity in C57Bl6/A2.01 mice and subsequently a robust frequency of protection (11/12 animals) after experimental challenge with subtype A or B HIV-1/Murine Leukemia Virus (HIV-1/MuLV). The cross-clade protection observed in this challenge experiment demonstrates that these multigene/multiepitope HIV DNA immunogens are likely to be potent immunogens also against the HIV-infection of human beings.

A DNA HIV-1 vaccine based on a fusion gene expressing non-structural and structural genes of consensus sequence of the A-C subtypes and the ancestor sequence of the F-H subtypes. Preclinical and clinical studies.

A potent DNA vaccine against HIV, combining a vector that takes advantage of the segregation and compartmentalization effect of bovine papilloma virus E2 protein with MultiHIV insert, expressing a fusion gene coding for the non-structural and structural proteins was developed and tested for immunogenicity in mice and humans.

Autoimmune regulator induced changes in the gene expression profile of human monocyte-dendritic cell-lineage.

The autoimmune regulator (AIRE) is a transcriptional regulator expressed in the thymic medullary epithelial cells and in the cells of the monocyte-dendritic lineage both in the thymus and in the secondary lymphoid organs. Mutations in the AIRE gene cause autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a recessively inherited disease characterized by loss of immunological self-tolerance to multiple endocrine organs. Recent mouse knockout studies suggest that AIRE is responsible for ectopic expression of peripheral self-antigens in the thymus. In the present study, we detected an increased level of endogenous AIRE expression during the differentiation process of the human monocyte derived dendritic cells (MoDCs). We subsequently identified candidates for AIRE-regulated genes by using cDNA microarray technology to analyse the changes in the gene expression profile brought about by overexpressing the AIRE protein in the monocytic U937 cells. The changes observed resembled those previously reported to occur during the maturation of DCs, including up-regulation of the CCL22, CD25, ICAM-1 and RelB genes. In contrast, increased expression of the steroidogenic enzymes P450c17, P450c21 and P450scc, the major autoantigens in APECED, was not found either in our cell model or in the dendritic cell cultures. We also identified the ERK signal transduction pathway as a candidate for mediating the signal that results in the altered expression profile. Our findings suggest that the role of AIRE in the DCs differs from its function in the thymus.