Browse
Submit Data
Databases
API
Help

Dataset Information

31 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Impact of Antigen Presentation Mechanisms on Immune Response in Autoimmune Hepatitis

ABSTRACT: The liver is a very tolerogenic organ. It is continually exposed to a multitude of antigens and is able to promote an effective immune response against pathogens and simultaneously immune tolerance against self-antigens. In spite of strong peripheral and central tolerogenic mechanisms, loss of tolerance can occur in autoimmune liver diseases, such as autoimmune hepatitis (AIH) through a combination of genetic predisposition, environmental factors, and an imbalance in immunological regulatory mechanisms. The liver hosts several types of conventional resident antigen presenting cells (APCs) such as dendritic cells, B cells and macrophages (Kupffer cells), and unconventional APCs including liver sinusoidal endothelial cells, hepatic stellate cells and hepatocytes. By standard (direct presentation and cross-presentation) and alternative mechanisms (cross-dressing and MHC class II-dressing), liver APCs presents self-antigen to naive T cells in the presence of costimulation leading to an altered immune response that results in liver injury and inflammation. Additionally, the transport of antigens and antigen:MHC complexes by trogocytosis and extracellular vesicles between different cells in the liver contributes to enhance antigen presentation and amplify autoimmune response. Here, we focus on the impact of antigen presentation on the immune response in the liver and on the functional role of the immune cells in the induction of liver inflammation. A better understanding of these key pathogenic aspects could facilitate the establishment of novel therapeutic strategies in AIH.

SUBMITTER: Fasano R

PROVIDER: S-EPMC8804214 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Role of age in presentation, response to therapy and outcome of autoimmune hepatitis.

Project description:BackgroundFew studies with diverging results and a small sample size have compared autoimmune hepatitis (AIH) in the elderly to younger patients.AimTo unbiasedly investigate the role of age in behaviour and treatment outcome of AIH.MethodsAll patients with probable or definite AIH type 1 in four tertiary academic centres were included in this retrospective-and since 2006 prospective-cohort study. Influence of age on presentation, remission and outcome of AIH were investigated.Results359 patients were included. Presence of cirrhosis at AIH diagnosis around 30% was independent of age. ALAT was higher at age 30-60 years on AIH diagnosis, and above age 60 there were less acute onset, less jaundice and more concurrent autoimmune disease. Remission was reached in 80.2%, incomplete remission in 18.7%, only 1.1% (all aged 50-65) was treatment-refractory. Age was not an independent predictor of remission, while cirrhosis was. Above age 45 there was more diabetes, above age 60 more loss of remission. Rate of progression to cirrhosis was 10% in the 10 years after diagnosis and unrelated to age at AIH diagnosis. With onset below age 30, there was more development of decompensated cirrhosis over time. With higher age at AIH diagnosis there was a lower survival free of liver-related death or liver transplantation.ConclusionsAIH presents at all ages. Age influences features at diagnosis, but not response to treatment, while survival without liver-related death or liver transplantation decreases with higher age at diagnosis.

| S-EPMC6026593 | biostudies-literature

Manipulating antigen presentation for antigen-specific immunotherapy of autoimmune diseases.

Project description:Current treatments for autoimmune diseases do not address the immune pathology underlying their initiation and progression and too often rely on non-specific immunosuppressive drugs for control of symptoms. Antigen-specific immunotherapy aims to induce tolerance selectively among the cells causing the disease while leaving the rest of the adaptive immune system capable of protecting against infectious diseases and cancers. Here we describe how novel approaches for antigen-specific immunotherapy are designed to manipulate antigen presentation and promote tolerance to specific self-antigens. This analysis points to liver antigen presenting cells, targeted by carrier particles, and steady-state dendritic cells, to which antigen-processing independent T-cell epitopes (apitopes) bind directly, as the principal targets for antigen-specific immunotherapy. Delivery of antigens to these cells holds great promise for effective control of this rapidly expanding group of diseases.

| S-EPMC8376632 | biostudies-literature

Clinical presentation of autoimmune hepatitis in Pakistani children.

Project description:Introduction:Autoimmune hepatitis (AIH) is one of the most common disorder resulting in end stage liver disease (ESLD) among children. Scarce data is available in this regard from Pakistan. In this study we have analyzed clinical and biochemical parameters of children suffering from this disorder. Methods:It was a cross sectional study conducted in the Department of Hepatogastroenterology, Sindh Institute of Urology and Transplantation (SIUT) Karachi from January 2005 to June 2016. Patients aged up-to 18 years were included. AIH was diagnosed by using International Autoimmune hepatitis group (IAIHG) pre-treatment and simplified AIH score. Patients with both probable and definite score were included. Biochemical, serological, sonographic and demographics were recorded at the time of diagnosis, liver biopsy was also performed in most of the cases. Data was analyzed by using SPSS ver.20 and p-value of < 0.05 was considered significant. Results:Total 51 patients were enrolled most of them were females (68.6%). Mean age of presentation was around 10 years. Males had statistically significant earlier age of presentation, p-value = 0.007. The most common presenting complain was jaundice. Hypergammaglobulinemia is seen in almost all patients. Type I AIH was the most common entity while Type II AIH was statistically more significant in males p-value = 0.019. Raised GGT was also seen in male patient specifically in Type II AIH, p-value = 0.001. Conclusion:Autoimmune hepatitis predominantly affects female children who have late age of presentation as compare to the males. Type I AIH was the most common while Type II AIH was more common in males and they also had raised GGT.

| S-EPMC6196082 | biostudies-other

Antigen presentation by keratinocytes directs autoimmune skin disease.

Project description:The antigen-presenting cells that initiate and maintain MHC class II-associated organ-specific autoimmune diseases are poorly defined. We now describe a new T cell antigen receptor (TCR) transgenic (Tg) model of inflammatory skin disease in which keratinocytes activate and are the primary target of autoreactive CD4(+) T cells. We previously generated keratin 14 (K14)-A(beta)b mice expressing MHC class II only on thymic cortical epithelium. CD4(+) T cells from K14-A(beta)b mice fail to undergo negative selection and thus have significant autoreactivity. The TCR genes from an autoreactive K14-A(beta)b CD4 hybridoma were cloned to produce a TCR Tg mouse, 2-2-3. 2-2-3 TCR Tg cells are negatively selected in WT C57BL6 mice but not in 2-2-3K14-A(beta)b mice. Interestingly, a significant number of mice that express both the K14-A(beta)b transgene and the autoreactive 2-2-3 TCR spontaneously develop inflammatory skin disease with mononuclear infiltrates, induction of MHC class II expression on keratinocytes, and T helper 1 cytokines. Disease can be induced by skin inflammation but not solely by activation of T cells. Thus, cutaneous immunopathology can be directed through antigen presentation by tissue-resident keratinocytes to autoreactive TCR Tg CD4(+) cells.

| S-EPMC152302 | biostudies-literature

Gut microbiota modulate dendritic cell antigen presentation and radiotherapy-induced antitumor immune response.

Project description:Alterations in gut microbiota impact the pathophysiology of several diseases, including cancer. Radiotherapy (RT), an established curative and palliative cancer treatment, exerts potent immune modulatory effects, inducing tumor-associated antigen (TAA) cross-priming with antitumor CD8+ T cell elicitation and abscopal effects. We tested whether the gut microbiota modulates antitumor immune response following RT distal to the gut. Vancomycin, an antibiotic that acts mainly on gram-positive bacteria and is restricted to the gut, potentiated the RT-induced antitumor immune response and tumor growth inhibition. This synergy was dependent on TAA cross presentation to cytolytic CD8+ T cells and on IFN-γ. Notably, butyrate, a metabolite produced by the vancomycin-depleted gut bacteria, abrogated the vancomycin effect. In conclusion, depletion of vancomycin-sensitive bacteria enhances the antitumor activity of RT, which has important clinical ramifications.

| S-EPMC6934221 | biostudies-literature

Clinical and Pathological Characteristics of Autoimmune Hepatitis with Acute Presentation.

Project description:Aim. To study the differences between acute presentation-autoimmune hepatitis (A-AIH) and chronic autoimmune hepatitis (C-AIH). Methods. Through long-term follow-up, 80 patients were included in our study by using the revised international autoimmune hepatitis group (IAIHG) score and were divided into acute and chronic groups for comparison. Results. No significant difference was found in the gender, age, IAIHG score (pretreatment/posttreatment), definite diagnosis rate, extrahepatic autoimmune disease, onset time, or treatment before biopsy between the acute and chronic groups. In terms of clinical symptoms, A-AIH patients were more prone to jaundice, anorexia, yellow urine, and detesting oil than C-AIH patients, but melena only occurred in chronic group (P < 0.05). The acute group exhibited more severe injury upon histological evaluation, with lobular inflammation and bile duct injury, especially central necrosis of the lobule, more pronounced in this group (P < 0.05). Conclusion. A-AIH had manifestations of acute hepatitis and presented cholestasis. Serum indicators could preliminarily distinguish A-AIH and C-AIH. Histologically, the primary manifestation of A-AIH was lobular inflammation, which was usually accompanied by lobular central necrosis. For the diagnosis of A-AIH, more attention should be paid to long-term follow-up. This study was registered at ClinicalTrials.gov (identifier: NCT02994537).

| S-EPMC5878912 | biostudies-literature

Mechanisms and Consequences of Antigen Presentation by CD1.

Project description:The CD1 proteins are a family of non-polymorphic and MHC class I-related molecules that present lipid antigens to subsets of T lymphocytes with innate- or adaptive-like immune functions. Recent studies have provided new insight into the identity of immunogenic CD1 antigens and the mechanisms that control the generation and loading of these antigens onto CD1 molecules. Furthermore, substantial progress has been made in identifying CD1-restricted T cells and decoding the diverse immunological functions of distinct CD1-restricted T cell subsets. These findings shed new light on the contributions of the CD1 antigen-presentation pathway to normal health and to a diverse array of pathologies, and provide a new impetus for exploiting this fascinating recognition system for the development of vaccines and immunotherapies.

| S-EPMC5159200 | biostudies-literature

Evaluation of RNA Amplification Methods to Improve DC Immunotherapy Antigen Presentation and Immune Response.

Project description:Dendritic cells (DCs) transfected with total amplified tumor cell RNA have the potential to induce broad antitumor immune responses. However, analytical methods required for quantitatively assessing the integrity, fidelity, and functionality of the amplified RNA are lacking. We have developed a series of assays including gel electrophoresis, northern blot, capping efficiency, and microarray analysis to determine integrity and fidelity and a model system to assess functionality after transfection into human DCs. We employed these tools to demonstrate that modifications to our previously reported total cellular RNA amplification process including the use of the Fast Start High Fidelity (FSHF) PCR enzyme, T7 Powerswitch primer, post-transcriptional capping and incorporation of a type 1 cap result in amplification of longer transcripts, greater translational competence, and a higher fidelity representation of the starting total RNA population. To study the properties of amplified RNA after transfection into human DCs, we measured protein expression levels of defined antigens coamplified with the starting total RNA populations and measured antigen-specific T cell expansion in autologous DC-T cell co-cultured in vitro. We conclude from these analyses that the improved RNA amplification process results in superior protein expression levels and a greater capacity of the transfected DCs to induce multifunctional antigen-specific memory T cells.Molecular Therapy-Nucleic Acids (2013) 2, e91; doi:10.1038/mtna.2013.18; published online 7 May 2013.

| S-EPMC4817939 | biostudies-literature

Antigen presentation, autoantibody production, and therapeutic targets in autoimmune liver disease.

Project description:The liver is an important immunological organ that controls systemic tolerance. The liver harbors professional and unconventional antigen-presenting cells that are crucial for tolerance induction and maintenance. Orchestrating the immune response in homeostasis depends on a healthy and well-toned immunological liver microenvironment, which is maintained by the crosstalk of liver-resident antigen-presenting cells and intrahepatic and liver-infiltrating leukocytes. In response to pathogens or autoantigens, tolerance is disrupted by unknown mechanisms. Intrahepatic parenchymal and nonparenchymal cells exhibit unique antigen-presenting properties. The presentation of microbial and endogenous lipid-, metabolite- and peptide-derived antigens from the gut via conventional and nonconventional mechanisms can educate intrahepatic immune cells and elicit effector responses or tolerance. Perturbation of this balance results in autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. Although the exact etiologies of these autoimmune liver diseases are unknown, it is thought that the disruption of tolerance towards self-antigens and microbial metabolites and lipids, as well as alterations in bile acid composition, may result in changes in effector cell activation and polarization and may reduce or impair protective anti-inflammatory regulatory T and B cell responses. Additionally, the canonical and noncanonical transmission of antigens and antigen:MHC complexes via trogocytosis or extracellular vesicles between different (non) immune cells in the liver may play a role in the induction of hepatic inflammation and tolerance. Here, we summarize emerging aspects of antigen presentation, autoantibody production, and the application of novel therapeutic approaches in the characterization and treatment of autoimmune liver diseases.

| S-EPMC7852534 | biostudies-literature