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1.
Clin Exp Immunol ; 2023 Oct 12.
Article En | MEDLINE | ID: mdl-37823420

There was evidence that pANCA (perinuclear antineutrophil cytoplasmic antibodies) in autoimmune liver diseases react with human beta-tubulin-5 (TBB5). Here we re-evaluate the specificity and clinical relevance of anti-TBB5 antibodies. Patients with untreated autoimmune hepatitis (AIH; n=53), AIH under immunosuppressive therapy (AIH-IS; n=125), primary sclerosing cholangitis (PSC; n=40), primary biliary cholangitis (PBC; n=250), non-autoimmune liver diseases (n=158), inflammatory bowel diseases (IBD; n=30), and healthy individuals (n=62) were tested by enzyme linked immunosorbent assay (ELISA) for IgG- and IgA-antibodies against recombinant human TBB5. pANCA were detected by immunofluorescence test. Sera were absorbed with TBB5 coupled to cyanogen bromide-activated sepharose. Prevalence and reactivity of IgG anti-TBB5 were significantly higher in patients with untreated AIH (68%; arbitrary units [AU] median:369) than in PSC (28%; AU median:84, p<0.001), other liver diseases (14%; AU median:185, p<0.0001), IBD (3%; AU median:111, p<0.0001) and healthy controls (3%; AU median:135; p<0.0001). Anti-TBB5 did not correlate with pANCA, and immunoprecipitation with TBB5 did not abolish pANCA reactivity. In untreated AIH anti-TBB5-reactivity was significantly higher than in AIH-IS. Transaminases decreased under IS preferentially in anti-TBB5 negative patients. There was no correlation between anti-TBB5-reactivity and histological stages. IgA-anti-TBB5 was mainly found in alcohol-associated liver disease (ALD; 39%). Our data do not support TBB5 as an autoantigenic target of pANCA. However, IgG-anti-TBB5 showed high specificity for (untreated) AIH. While they did not correlate with histological and laboratory parameters, their presence may indicate a poor response to IS.

2.
Autoimmun Rev ; 22(5): 103310, 2023 May.
Article En | MEDLINE | ID: mdl-36906052

G protein-coupled receptors (GPCR) are involved in various physiological and pathophysiological processes. Functional autoantibodies targeting GPCRs have been associated with multiple disease manifestations in this context. Here we summarize and discuss the relevant findings and concepts presented in the biennial International Meeting on autoantibodies targeting GPCRs (the 4th Symposium), held in Lübeck, Germany, 15-16 September 2022. The symposium focused on the current knowledge of these autoantibodies' role in various diseases, such as cardiovascular, renal, infectious (COVID-19), and autoimmune diseases (e.g., systemic sclerosis and systemic lupus erythematosus). Beyond their association with disease phenotypes, intense research related to the mechanistic action of these autoantibodies on immune regulation and pathogenesis has been developed, underscoring the role of autoantibodies targeting GPCRs on disease outcomes and etiopathogenesis. The observation repeatedly highlighted that autoantibodies targeting GPCRs could also be present in healthy individuals, suggesting that anti-GPCR autoantibodies play a physiologic role in modeling the course of diseases. Since numerous therapies targeting GPCRs have been developed, including small molecules and monoclonal antibodies designed for treating cancer, infections, metabolic disorders, or inflammatory conditions, anti-GPCR autoantibodies themselves can serve as therapeutic targets to reduce patients' morbidity and mortality, representing a new area for the development of novel therapeutic interventions.


Autoimmune Diseases , COVID-19 , Humans , Autoantibodies , Autoimmunity , Receptors, G-Protein-Coupled/metabolism
3.
Rheumatology (Oxford) ; 62(6): 2168-2177, 2023 06 01.
Article En | MEDLINE | ID: mdl-36222553

OBJECTIVES: To evaluate the effect of autologous stem cell transplantation (aSCT) on functional antibodies (abs) to the angiotensin II type-1-receptor (AT1R) and topoisomerase-I (topo-I) in SSc-patients and to analyse their prognostic relevance. MATERIAL AND METHODS: Forty-three SSc-patients in whom aSCT was performed were analysed. Thirty-one patients had a favourable outcome after aSCT (group 1), 12 patients showed no response or relapse (group 2). Patients' sera were tested for anti-AT1R and anti-topo-I antibodies by ELISA and in a luminometric assay (LA) using AT1R-expressing Huh7-cells for inhibitory or stimulatory anti-AT1R antibodies before and after aSCT (4-217 months, median 28 months). Anti-topo-I antibodies were also analysed for their capacity to inhibit enzyme function. RESULTS: A total of 70% of the SSc patients had anti-topo-I- and 51% anti-AT1R antibodies in the ELISA before aSCT. In all instances, anti-topo-I antibodies inhibited topo-I-enzyme function. In the LA, 40% had stimulatory and 12% inhibitory anti-AT1R antibodies. Anti-topo-I- and anti-AT1R-reactivity (ELISA) significantly decreased after aSCT. Before aSCT, anti-topo-I-reactivity was significantly higher in group 2 patients than in group 1 patients (P < 0.001), while there was no difference between both groups for anti-AT1R antibodies detected by ELISA. Stimulatory anti-AT1R antibodies detected by LA were confined to group 1-patients. CONCLUSIONS: Reactivity of functionally active anti-AT1R antibodies was not influenced by aSCT, while anti-topo-I antibodies decreased after aSCT. The fact that anti-topo-I antibodies inhibited enzyme function in all instances supports the hypothesis of a pathogenetic role of the topo-I antigen/antibody-system in SSc. High anti-topo-I reactivity before aSCT was associated with an unfavourable, presence of stimulatory anti-AT1R antibodies with a favourable course after aSCT.


Hematopoietic Stem Cell Transplantation , Scleroderma, Systemic , Humans , Autoantibodies , Transplantation, Autologous , Scleroderma, Systemic/complications , Enzyme-Linked Immunosorbent Assay , DNA Topoisomerases, Type I
4.
J Clin Med ; 11(3)2022 Jan 28.
Article En | MEDLINE | ID: mdl-35160133

BACKGROUND: Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) constitute rare chronic inflammatory biliary diseases which likely comprise genetic, environmental and autoimmune factors. Specific inhibitory (auto-) antibodies against the muscarinic acetylcholine receptor type 3 (mAChR3 auto-ab) may contribute to the pathogenesis of chronic biliary inflammation by modulating mAChR3- mediated signaling. AIMS: The aim of this study was to analyze the prevalence and relevance of inhibitory mAChR3 auto-ab (mAChR3inh+ auto-ab) in a large cohort of PBC patients from two independent tertiary centers in Berlin and Leipzig in comparison to a large PSC cohort. Baseline parameters and response rates to standard treatment with ursodeoxycholic acid (UDCA) were characterized with respect to the individual mAChR3 auto-ab status. METHODS: In total, the study population comprised 437 PBC patients, 187 PSC patients and 80 healthy controls. Clinical and laboratory baseline characteristics were retrieved from medical records. The response to ursodeoxycholic acid (UDCA) therapy after 12 months of treatment was available in 176 PBC and 45 PSC patients. RESULTS: The prevalence of mAChR3inh+ auto-ab was significantly higher among PBC patients (11.2%, 49/437; p = 0.008 vs. healthy controls) and PSC patients (33.6%, 63/187; p < 0.0001 vs. healthy controls) compared to healthy controls (2.5%, 2/80), respectively. PBC patients with mAChR3inh+ auto-ab exhibited significantly higher levels of alkaline phosphatase (ALP) and bilirubin, which constitute established parameters for PBC risk stratification. Moreover, mAChR3inh+ PBC patients tended to show decreased response rates to UDCA therapy compared to PBC patients without mAChR3inh+ auto-ab (mAChR3- PBC). In contrast, PSC patients with mAChR3inh+ auto-ab showed no significant differences in laboratory findings compared to mAChR3 auto-ab negative (mAChR3-) PSC patients. CONCLUSION: MAChR3inh+ auto-ab might be involved in the pathogenesis and treatment response of chronic biliary inflammation in patients with PBC but not in patients with PSC.

5.
Front Immunol ; 12: 786039, 2021.
Article En | MEDLINE | ID: mdl-34956217

Objectives: 1) To detect functionally active antibodies(abs) to the angiotensin II type-1-receptor (AT1R) by a novel luminometric assay. 2) To assess their prevalence in systemic sclerosis (SSc), other collagen disorders, as well as in further chronic inflammatory disorders including autoimmune, toxic and chronic viral diseases. 3) To compare these abs with anti-AT1R antibodies by ELISA as well as with antibodies to endothelin-type-A receptors (ETA1) and to topoisomerase I (topo-I) with respect to their specificity and clinical relevance. Methods: Sera from 98 SSc-patients, 110 patients with other chronic inflammatory rheumatic disorders, 97 patients with autoimmune liver diseases, 57 patients with toxic or chronic viral liver diseases and 36 healthy controls were analyzed. A luminometric bioassay was established with Huh-7-cells constitutively expressing the AT1R. Patients' sera were also tested by commercially available ELISA for anti-AT1R, -ETA1- and by an in-house ELISA for anti-topo-I-abs. Results: Fifty-two percent of the SSc-patients had functionally active anti-AT1R-abs with stimulatory (34%) or inhibitory capacity (18%). They were present also in up to 59% of patients with other rheumatic diseases but only 22% of healthy individuals (sensitivity 52%, specificity 53%). The functionally active antibodies detected by the luminometric assay did not correlate with anti-AT1R-, -ETA1- or -topo-I-abs measured by ELISA, but there was a strong correlation between anti-topo-I-, AT1R-, and -ETA1-ab reactivity measured by ELISA. Sensitivities of 55%, 28% and 47% and specificities of 66%, 87%, and 99% were calculated for these anti-AT1R-, -ETA1-, and anti-topo-I-abs, respectively. Functionally active abs did not correlate with disease severity or any organ manifestation. In contrast, abs to topo-I, AT1R, and ETA1 were associated with digital ulcers, pulmonary- and esophageal manifestation. Conclusions: Functionally active anti-AT1R-abs can be detected in SSc-patients but do not correlate with disease activity. They are not specific for this disease and occur also in other autoimmune disorders and even viral or toxic diseases. Also, the vascular antibodies detected by ELISA are not SSc-specific but correlated with disease manifestations. In contrast, anti-topo-I-abs were confirmed to be a highly specific biomarker for both, diagnosis and organ manifestations of SSc.


Autoantibodies/blood , DNA Topoisomerases, Type I/immunology , Receptor, Angiotensin, Type 1/immunology , Scleroderma, Systemic/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Autoantibodies/immunology , Biological Assay/methods , Biomarkers/blood , Cell Line, Tumor , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Receptor, Endothelin A/immunology , Scleroderma, Systemic/blood , Scleroderma, Systemic/immunology , Sensitivity and Specificity , Severity of Illness Index , Young Adult
6.
Vaccines (Basel) ; 9(5)2021 Apr 24.
Article En | MEDLINE | ID: mdl-33923363

We describe the results of two vaccinations of a self-experimenting healthy volunteer with SARS-CoV-2-derived peptides performed in March and April 2020, respectively. The first set of peptides contained eight peptides predicted to bind to the individual's HLA molecules. The second set consisted of ten peptides predicted to bind promiscuously to several HLA-DR allotypes. The vaccine formulation contained the new TLR 1/2 agonist XS15 and was administered as an emulsion in Montanide as a single subcutaneous injection. Peripheral blood mononuclear cells isolated from blood drawn before and after vaccinations were assessed using Interferon-γ ELISpot assays and intracellular cytokine staining. We detected vaccine-induced CD4 T cell responses against six out of 11 peptides predicted to bind to HLA-DR after 19 days, following vaccination, for one peptide already at day 12. We used these results to support the design of a T-cell-inducing vaccine for application in high-risk patients, with weakened lymphocyte performance. Meanwhile, an according vaccine, incorporating T cell epitopes predominant in convalescents, is undergoing clinical trial testing.

7.
Nat Immunol ; 22(1): 74-85, 2021 01.
Article En | MEDLINE | ID: mdl-32999467

T cell immunity is central for the control of viral infections. To characterize T cell immunity, but also for the development of vaccines, identification of exact viral T cell epitopes is fundamental. Here we identify and characterize multiple dominant and subdominant SARS-CoV-2 HLA class I and HLA-DR peptides as potential T cell epitopes in COVID-19 convalescent and unexposed individuals. SARS-CoV-2-specific peptides enabled detection of post-infectious T cell immunity, even in seronegative convalescent individuals. Cross-reactive SARS-CoV-2 peptides revealed pre-existing T cell responses in 81% of unexposed individuals and validated similarity with common cold coronaviruses, providing a functional basis for heterologous immunity in SARS-CoV-2 infection. Diversity of SARS-CoV-2 T cell responses was associated with mild symptoms of COVID-19, providing evidence that immunity requires recognition of multiple epitopes. Together, the proposed SARS-CoV-2 T cell epitopes enable identification of heterologous and post-infectious T cell immunity and facilitate development of diagnostic, preventive and therapeutic measures for COVID-19.


COVID-19/immunology , Epitopes, T-Lymphocyte/immunology , Peptides/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Viral Vaccines/immunology , COVID-19/prevention & control , COVID-19/virology , Cross Reactions/immunology , HLA-DR Antigens/immunology , HLA-DR Antigens/metabolism , Histocompatibility Antigens Class I/immunology , Histocompatibility Antigens Class I/metabolism , Humans , Immunologic Memory/immunology , SARS-CoV-2/physiology , T-Lymphocytes/metabolism , Viral Vaccines/administration & dosage
8.
Front Immunol ; 11: 1151, 2020.
Article En | MEDLINE | ID: mdl-32695096

Background and Aims: In primary biliary cholangitis (PBC), antibodies to a peptide of the muscarinic acetylcholine receptor 3 (mAChR3) have been described. Since the mAChR3 is expressed on cholangiocytes and mAChR3-signaling is involved in the pathogenesis of chronic inflammatory biliary diseases, we wanted to investigate whether anti-mAChR3-antibodies influence the function of the receptor and the proliferative response of cholangiocytes. Methods: Immunoglobulins were isolated by ammonium sulfate precipitation using sera from patients with PBC (n = 63) and with other chronic liver disorders (n = 150). All immunoglobulins were analyzed by a luminometric assay using Chinese hamster ovary (CHO) cells overexpressing the mAChR3 and cholangiocytes (TFK-1-cells) expressing the receptor constitutively. Cell proliferation was measured by 3H-thymidine assay. PBC patients were also analyzed in the follow-up. Results: Antibodies inhibiting the mAChR3 were found in 49 and 79% of PBC patients using CHO-cells or TFK-1-cells, respectively, but only in up to 26% of controls (p < 0.01). Stimulatory antibodies were hardly detected. Antibody reactivity only marginally changed during the course of the disease, independently of the choice of treatment (ursodeoxycholic acid, immunosuppressive therapy, or no medication). There was no correlation with laboratory, clinical or histological parameters, but the antibodies were more frequently found in PBC patients with a benign course (96%) than in patients with active disease progressing to late stages within 10 years (57%; p < 0.01). Proliferation of cells was not influenced by immunoglobulins from PBC-patients. Conclusion: Sera from patients with PBC contain inhibitory antibodies to the mAChR3 on cholangiocytes (TFK-1 cells) without influencing TFK-1-cell proliferation. These antibodies were predominantly observed in patients with non-progressing PBC.


Autoantibodies/immunology , Liver Cirrhosis, Biliary/immunology , Receptor, Muscarinic M3/immunology , Adult , Aged , Aged, 80 and over , Animals , Autoantigens/immunology , CHO Cells , Cricetulus , Female , Humans , Male , Middle Aged , Young Adult
9.
BMC Gastroenterol ; 18(1): 58, 2018 May 02.
Article En | MEDLINE | ID: mdl-29720090

BACKGROUND: In a recent study we had evidence that sulphite oxidase (SO) may be a relevant autoantigen in primary sclerosing cholangitis (PSC). Aim of the present study was, therefore, to analyse humoral and cellular immune-reactivity towards SO in these patients in more detail. METHODS: Sera from 53 patients with PSC (30 untreated and 23 treated with ursodeoxycholic acid [UDCA] at time of analysis), from 422 patients with different hepatic and non-hepatic disorders, and from 50 healthy individuals were tested by ELISA for antibodies against full-length-SO (SO-fl) and its three major domains expressed in E.coli (SO-I, SO-II, SO-III). For epitope-mapping, 29 overlapping peptides were used. Peripheral blood mononuclear cells (PBMC) were obtained from 33 PSC-patients and analysed for SO-induced proliferation, production of cytokines, and expression of the activation marker cluster of differentiation (CD) 69. RESULTS: 43% of the 30 untreated and 26% of the 23 treated PSC-patients had IgG anti-SO-antibodies predominantly reacting with SO-fl, SO-I and SO-II. Antibody-reactivity decreased after UDCA-treatment. Prevalence and reactivity of anti-SO-antibodies were significantly higher in PSC than in patients with other hepatic and non-hepatic disorders. Epitope mapping revealed no distinct immuno-dominant regions within SO. Incubation of PBMC from PSC-patients (but not from controls) with SO-antigens revealed an activation of B-cells and a T-helper cell type-2 reaction pattern (production of interleukin [IL]-13, IL-10). CONCLUSIONS: PSC-patients show humoral and cellular immune response towards SO. Antibodies may be predominantly directed against conformational epitopes. SO enhances in vitro especially T-helper cell type-2 immune-reactions, which may be pro-fibrotic. SO is a detoxifying enzyme present also in bacteria; further studies analysing its role in the aetiology and pathogenesis in PSC may, therefore, be important.


Autoantibodies/blood , Autoantigens/immunology , Cholangitis, Sclerosing/immunology , Immunity, Cellular , Immunity, Humoral , Mitochondria/enzymology , Sulfite Oxidase/immunology , Adolescent , Adult , Aged , B-Lymphocytes/physiology , Cholagogues and Choleretics/therapeutic use , Cholangitis, Sclerosing/drug therapy , Epitope Mapping , Female , Gene Expression , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Lymphocyte Activation , Male , Middle Aged , Sulfite Oxidase/genetics , Th2 Cells/physiology , Ursodeoxycholic Acid/therapeutic use , Young Adult
10.
BMC Gastroenterol ; 12: 152, 2012 Oct 24.
Article En | MEDLINE | ID: mdl-23095491

BACKGROUND: In a recent study we showed that in patients with primary biliary cirrhosis (PBC) being positive or negative for anti-M2 antibodies reacting with the 2-oxoacid-dehydrogenase complex (ODC) also antibodies to the beta- and gamma-subunits of F1F0-ATPase (anti-ß, anti-γ) occur. This is a mitochondrial enzyme but parts are also expressed on plasma membranes of endothelial cells. Here we wanted to analyse in more detail their clinical relevance. METHODS: Fifty-nine untreated and histologically defined PBC patients who had been followed for at least five years were included into the study (51 anti-M2 positive, 8 anti-M2 negative). Twenty-three of them were treated in the follow up with ursodeoxycholic acid (UDCA), eight received during a trial methotrexate (MTX). In 13 patients orthotopic liver transplantation (OLT) had to be performed. Serum samples before and during therapy were available. Patients were analysed with respect to laboratory parameters, disease activity and histological stages.Patients' sera were tested by ELISA for IgG- and IgM-antibodies against the beta- and gamma-subunits which had been recombinant expressed in E.coli and highly purified by electro-elution from SDS-gels after electrophoresis. RESULTS: Fifty-nine percent of the anti-M2 positive and 50% of the anti-M2 negative PBC patients had anti-ß- and/or anti-γ-antibodies. There were no differences between anti-ß- and/or anti-γ-antibody positive or negative patients with respect to biochemical parameters, immunoglobulins, histological stages or disease activity. Antibody reactivity significantly decreased during UDCA and MTX-treatment and also after OLT. CONCLUSIONS: Antibodies to the ß- and γ-subunits of F1F0-ATPase occur in anti-M2 positive and -negative PBC but do not have any relevance with respect to clinical activity or prognosis. However, in contrast to the anti-M2 antibodies they decrease during UDCA and immunosuppressive therapy.


Autoantibodies/immunology , Liver Cirrhosis, Biliary/immunology , Mitochondria, Liver/immunology , Proton-Translocating ATPases/immunology , Adult , Age of Onset , Autoantibodies/blood , Cholagogues and Choleretics/therapeutic use , Female , Humans , Liver Cirrhosis, Biliary/drug therapy , Liver Cirrhosis, Biliary/surgery , Liver Transplantation , Longitudinal Studies , Male , Methotrexate/therapeutic use , Middle Aged , Treatment Outcome , Ursodeoxycholic Acid/therapeutic use , Young Adult
11.
Liver Int ; 32(2): 249-57, 2012 Feb.
Article En | MEDLINE | ID: mdl-22098431

BACKGROUND AND AIMS: Recently, a non-M2-related mitochondrial 60 kDa protein found to be recognized by antimitochondrial antibody (AMA) negative sera from patients with primary biliary cirrhosis (PBC) has been shown to contain parts of the five F(1)-ATPase subunits α, ß, γ, δ and ε. In this study, we examined whether this enzyme is, indeed, a target antigen in PBC. METHODS: Analysed were 60 AMA-positive/anti-M2-negative and 103 anti-M2-positive PBC patients, 46 patients with autoimmune hepatitis (AIH), 35 patients with primary sclerosing cholangitis (PSC), 110 patients with viral hepatitis, 40 patients with inflammatory bowel diseases (IBD), 33 patients with connective tissue diseases (systemic lupus erythematosus, mixed connective tissue disease, Sjögren disease, systemic sclerosis) and 25 blood donors. The F(1)-ATPase-subunits α-δ were recombinantly expressed in Escherichia coli, purified and applied to ELISA and Western blotting. RESULTS: In all, 40 of the 60 AMA-positive/anti-M2-negative (67%) and 44 (43%) of the 103 anti-M2-positive PBC-sera reacted with at least one of the F(1)-subunits α-δ. The ß- and γ-subunits were preferentially recognized. However, also up to 57% of patients with AIH and 34% of patients with PSC had anti-ß- or γ-antibodies, while patients with viral hepatitis had these antibodies in up to 13%. Patients with IBD had anti-ß and anti-γ-antibodies in up to 20 and 5% respectively. None of the patients with connective tissue diseases had antibodies to the ß- and only 6% to the γ-subunit. Sera from healthy blood donors were negative. CONCLUSIONS: Antibodies to the ß- and γ-subunits of F(1)-ATPase are further AMAs in PBC but occur also in other autoimmune liver disorders; they may be, therefore, indicators for a general autoimmune process of the liver.


Autoantibodies/blood , Autoantigens/immunology , Hepatitis, Autoimmune/immunology , Mitochondrial Membranes/enzymology , Proton-Translocating ATPases/immunology , Adolescent , Adult , Aged , Child , Cholangitis, Sclerosing/blood , Cholangitis, Sclerosing/enzymology , Cholangitis, Sclerosing/immunology , Connective Tissue Diseases/blood , Connective Tissue Diseases/enzymology , Connective Tissue Diseases/immunology , Female , Hepatitis, Autoimmune/blood , Hepatitis, Autoimmune/enzymology , Hepatitis, Viral, Human/blood , Hepatitis, Viral, Human/enzymology , Hepatitis, Viral, Human/immunology , Humans , Inflammatory Bowel Diseases/blood , Inflammatory Bowel Diseases/enzymology , Inflammatory Bowel Diseases/immunology , Liver/pathology , Male , Middle Aged , Protein Subunits/genetics , Protein Subunits/immunology , Proton-Translocating ATPases/classification , Proton-Translocating ATPases/genetics , Young Adult
12.
Graefes Arch Clin Exp Ophthalmol ; 250(2): 297-305, 2012 Feb.
Article En | MEDLINE | ID: mdl-21842131

BACKGROUND: A high incidence of autoantibodies to lens proteins has been found in sera of patients with uveitis. We showed previously that the anti-lens antibodies reacted predominantly with α-crystallins. The aim of the present study was to identify immunodominant epitopes within the protein chains of human αA- and αB-crystallin. METHODS: Epitope specificities of antibodies to αA- and αB-crystallin were examined by ELISA using synthetic overlapping peptides, spanning the entire length of both α-crystallins. The peptides consisted of 25 amino acid residues, with an overlap of at least eight amino acids each. The synthetic peptides were tested against sera of 110 patients with different uveitis forms, classified according to anatomical location of intraocular inflammation. RESULTS: Four immunodominant regions within the protein chains of αA- and αB-crystallin could be identified. These regions were recognized by antibodies in sera of 56% of uveitis patients. Anti-lens antibodies of IgG-type reacted preferentially with regions located at amino acid (aa) residues aa:69-93 and aa:137-161 of αA-crystallin as well as aa:69-110 and aa:137-161 of αB-crystallin. IgM antibodies recognized predominantly region aa:149-173 of αA-crystallin, and aa:69-110 and aa:151-175 of αB-crystallin. IgM antibodies directed to peptide aa:69-93 of αB-crystallin were found in sera of 30% of patients with intermediate uveitis. CONCLUSIONS: Four immunodominant B-cell epitopes within the protein chains of αA- and αB-crystallin have been identified; however, no clear correlation with the anatomically defined uveitis subtypes has been found except for intermediate uveitis. Whether there may be a correlation with uveitis forms with similar etiopathogenesis has to be evaluated in further studies.


Autoantibodies/blood , Autoantigens/immunology , Immunodominant Epitopes/immunology , Uveitis/immunology , alpha-Crystallin A Chain/immunology , alpha-Crystallin B Chain/immunology , Adolescent , Adult , Aged , Amino Acid Sequence , Child , Cross Reactions , Enzyme-Linked Immunosorbent Assay , Epitope Mapping , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Molecular Sequence Data , Peptide Fragments/immunology
13.
Brain Behav Immun ; 25(2): 279-85, 2011 Feb.
Article En | MEDLINE | ID: mdl-20884345

In a previous study we found in 50% of patients with neuropsychiatric manifestations of systemic lupus erythematosus (NP-SLE) organ specific antibodies to 45-56 kD proteins in a 100,000 g supernatant (SN) from bovine brain mitochondria. Aim of the present study was to identify the corresponding target antigen. A 100,000 g SN from bovine brain mitochondria was applied to SDS-gel electrophoresis. A 50 kD band recognized by sera from patients with NP-SLE in the Western blot (WB) was excised from the gels and applied to mass spectrometry. The identified protein was expressed in Escherichia coli and retested against sera from eleven patients with NP-SLE (severe symptoms n=6, mild symptoms n=5), 26 SLE-patients without NP manifestations and 53 controls (patients with multiple sclerosis, epilepsy, healthy blood donors). Mass spectrometry of the 50 kD band revealed the presence of α-tubulin. Applying the recombinant α-tubulin in the WB, four of the eleven NP-SLE patients (36%), one of the 26 patients with SLE without NP manifestations (4%) and none of the 53 controls reacted with α-tubulin. The antibodies were more frequently found in patients with severe (50%) than with mild NP-SLE (20%). α-tubulin may be a novel marker autoantigen for a neuropsychiatric manifestation at least in a subgroup of patients with SLE. Whether anti-α-tubulin antibodies are of pathogenetic relevance has still to be clarified.


Autoantigens/immunology , Lupus Vasculitis, Central Nervous System/immunology , Tubulin/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Antibodies, Monoclonal/analysis , Antibody Specificity , Blotting, Western , Brain Chemistry/genetics , Cattle , Cloning, Molecular , Collagen Diseases/immunology , Collagen Diseases/pathology , DNA, Complementary/genetics , Electrophoresis, Polyacrylamide Gel , Female , Humans , Lupus Vasculitis, Central Nervous System/pathology , Male , Middle Aged , Mitochondria/metabolism , Multiple Sclerosis/pathology , Nerve Tissue Proteins/chemistry , Recombinant Proteins/genetics , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Tubulin/genetics , Young Adult
14.
Graefes Arch Clin Exp Ophthalmol ; 245(5): 683-8, 2007 May.
Article En | MEDLINE | ID: mdl-16988835

BACKGROUND: Uveitis is an intraocular inflammatory disease in which autoimmune reactions have been discussed in playing an important role. Many data in this respect derived from the animal model of "experimental autoimmune uveitis", where several organ-specific autoantigens have been described such as the retinal S-antigen and the interphotoreceptor retinoid-binding protein. However, their diagnostic and pathogenic role in humans has been controversially discussed. In recent studies, the possible relevance of betaB1-crystallin, present in lens and ciliary body, has been outlined. We, therefore, wanted to analyse whether sera from patients with uveitis might contain antibodies to lens proteins METHODS: Human lenses from cadaveric eyes were shock frozen, homogenized, and resuspended. The resulting suspension (human lens protein fraction--HLPF) was analyzed for antigenicity by ELISA and Western blotting with patients' sera. A total of 165 patients with uveitis, 54 patients with scleritis and episcleritis, 56 patients with other eye diseases, and 112 healthy blood donors were studied. RESULTS: Twenty-six (49%) of the 53 patients with anterior uveitis, 17 (32%) of the 53 patients with intermediate uveitis and 7 (22%) of 32 patients with posterior uveitis reacted in the ELISA with the HLPF. Antibodies to lens antigens were detected in one-third of patients with panuveitis and retinal vasculitis. In contrast, only 12% of the healthy blood donors were positive in the ELISA. The number of patients with an autoimmune response to alpha-crystallins in Western blot predominated in all investigated groups. CONCLUSIONS: These data indicate that antibodies to lens proteins occur in a high incidence in sera from patients with uveitis. Forty-nine percent of the patients with anterior uveitis and only 12% of healthy controls were positive in the ELISA. In our groups of patients and controls the autoantibodies reacted in the Western blot predominantly with alpha-crystallin. Further studies are required to analyze in more detail the clinical and etiopathogenetic relevance of the antilens antibodies in uveitis.


Autoantibodies/blood , Autoantigens/immunology , Crystallins/immunology , Uveitis/blood , Blotting, Western , Enzyme-Linked Immunosorbent Assay , Humans , Incidence , Scleritis/blood , alpha-Crystallins/immunology , beta-Crystallins/immunology
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