Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01889 (ankylosing spondylitis)
 5,717 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The association of HLA-B27 with ankylosing spondylitis and related spondyloarthropathies has been known for two decades and has provided a great impetus to the epidemiologic studies and also helped broaden the clinical spectrum of these diseases. The etiology of these diseases is likely to be multifactorial and include genetic, immunologic, and environmental mechanisms. The detailed three-dimensional x-ray crystallographic structure of B27 has now been reported. It has revealed electron density compatible with oligopeptides that are nine amino acid-long (nonamers) bound in the antigen-binding cleft of the molecule. Microsequence analysis of 11 peptides eluted from the antigen-binding cleft has confirmed that all are nonamers. The most restricted position in the bound peptide is the second position, where all the 11 peptides contain arginine. The side chain of arginine extends into the B pocket ("45 pocket"), which seems to act as a specificity side pocket in the antigen-binding cleft of the B27 molecule. It is very likely that an understanding of the detailed structure of B27, including the peptide-binding motif and the structural domains recognized by cytotoxic T cells, along with the recent development of the B27 transgenic rat model for spondyloarthropathies, will further enhance our understanding of the immunogenetics of these diseases. It is hoped that this will lead to the source of the arthritogenic triggers and possibly disease prevention by antigen-specific immunomodulation. Because T-cell activation is initiated by the formation of antigen-MHC complexes that are the ligands that are recognized by the antigen-specific T-cell receptor (TCR), it might be possible to inhibit this activation by blocking the antigen-binding cleft of MHC molecules by using high-affinity MHC-binding peptides (MHC blockade) or by a novel, new, and more efficient method of TCR antagonism.
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PMID:Immunogenetics of spondyloarthropathies. 145 47

The mechanism by which HLA-B27 confers genetic susceptibility to the seronegative spondyloarthropathies ankylosing spondylitis, Reiter's syndrome, and reactive arthritis, is not well understood. The current concept of an extraarticular bacterial infection functioning as the triggering event in a genetically susceptible host suggests the possibility of direct microbial-MHC interaction. We have addressed the role of HLA-B27 in microbial-host cell interaction by examining invasion by putatively arthritogenic gram-negative bacteria. Target cells used were murine L cells transfected with HLA-B27, HLA-A3, HLA-A2, HLA B44, HLA B18, or pSV2neo vector alone. Relative to the pSV2neo control and the HLA-A3 transfectant, HLA-B27-transfected cells demonstrated a consistent decrease in invasion for each of the following pathogens: Salmonella typhimurium (45 +/- 2% decrease), Shigella sonnei (53 +/- 13% decrease), Shigella flexneri (45 +/- 5% decrease), and enteroinvasive Escherichia coli (57 +/- 8% decrease). This decrease was specific for the HLA B27-transfected L cells and was not observed in the other B allele transfectants. The decreased invasion in the HLA-B27 transfectants is not the result of either altered endogenous mouse class I expression as a result of human class I transfection or increased intracellular bacterial killing within the B27 transfectants. There was an inverse relationship between the amount of surface expression of HLA-B27, as measured by FACS, and the degree of invasion. Blocking of surface B27 Ag with anti-B27 mAb augmented bacterial invasion in the B27 transfectants. These studies demonstrate a novel bacterial-B27 interaction that may have relevance to the pathogenesis of B27-related arthritis.
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PMID:HLA-B27 expression modulates gram-negative bacterial invasion into transfected L cells. 158 45

Several MHC (major histocompatibility complex) genes are associated with increased incidence of disease. The strongest association is between the class I gene, HLA-B27, and ankylosing spondylitis (AS). HLA-B27 is also highly associated with Reiter's syndrome. As not all subjects with HLA-B27 develop AS or Reiter's syndrome, environmental factors may have a key role in the pathogenesis of these arthritic diseases. Several studies have implicated klebsiella in the development of AS, whereas Reiter's syndrome may result from infection with yersinia, shigella, salmonella, campylobacter, or chlamydia. Transgenic mice present a unique opportunity to study the association of specific MHC genes and disease. HLA-B27 transgenic mice were produced to study the association of HLA-B27, bacterial infection, and arthritic disease. Mice with the HLA-B27 gene are more susceptible to intravenous infection with Yersinia enterocolitica 0:8 WA than negative litter mates as shown by a higher incidence of spinal abscesses and mortality. Understanding the mechanism(s) responsible for this difference may yield valuable insights into the pathogenesis of HLA-B27 associated disease in humans.
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PMID:Role of enterobacteria and HLA-B27 in spondyloarthropathies: studies with transgenic mice. 211 64

74 overlapping peptides of varying lengths from Klebsiella pneumoniae nitrogenase reductase (residues 181-199) and from the HLA B27.1 molecule (residues 65-85) were synthesized and tested by ELISA against sera from HLA B27+ ankylosing spondylitis (AS) patients, and sera from HLA B27+ and HLA B27- healthy first-degree relatives. Antibody activity in AS sera to Klebsiella peptides of four to eight amino acids was maximal with the peptide NSRQTDR. Activity to HLA B27 peptides was maximal with the peptide KAKAQTDR (named epitope I). These peptides overlap with, but are proximal to the NH2 terminus from QTDRED, which is homologous in HLA B27.1 and K. pneumoniae nitrogenase reductase. A second weaker reactive site was noted in the HLA B27.1 peptides, proximal to the COOH terminus from the homologous sequence, namely peptide REDLRTLL (named epitope II). Little activity was seen against peptides that included the entire homologous sequence. Sera from 50 AS patients showed higher total Ig activity against peptides KAKAQTDR (p less than 0.001) and NSRQTDR (p less than 0.02) than did sera from 22 B27+ and 22 B27- healthy controls. These data indicate that AS patient sera contain antibodies that bind to K. pneumoniae nitrogenase peptides and HLA B27.1 peptides, and that there are at least two epitopes on HLA B27.1 in the alpha 1 domain, at the MHC groove region, that are autoantigenic in AS patients. Epitope I may be a site for crossreactivity between HLA B27 and Klebsiella.
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PMID:Antibody activity in ankylosing spondylitis sera to two sites on HLA B27.1 at the MHC groove region (within sequence 65-85), and to a Klebsiella pneumoniae nitrogenase reductase peptide (within sequence 181-199). 218 31

Despite major advances in genetic and structural studies of the HLA-B27 antigen, the underlying mechanism responsible for the remarkable association between this antigen and spondylarthropathies remains unknown. At a molecular level, the use of B27M1 and B27M2 monoclonal antibodies has permitted the identification of distinct allospecific epitopes on the B27 molecule. One of these epitopes, B27M2, is polymorphic and has allowed us to define B27 variants: B27M2[+], B27M2[-], and B27M2[int]. The heterogeneity of the B27 antigen correlates well with biochemical and cytotoxic evidence of genetic heterogeneity. These variants exhibit ethnic variation and also appear to correlate, in preliminary studies, with disease susceptibility, especially among Orientals. HLA gene probing is potentially an even more precise tool than monoclonal antibodies for the study of MHC-related disease susceptibilities. Initial work in our laboratory has resulted in the production of probes with specificity for HLA-B locus genes and current efforts are directed toward the derivation of B27 allele-specific probes. It seems likely that, when such probes are applied to B27-positive individuals, complexity in addition to the B27M2 variants will be revealed. Yet to be defined is the mechanism behind the association between B27 and AS. Is the association causal for disease, or is B27 indeed just a marker for other pathogenic factors somehow linked to it? Available evidence points to both causal and linked roles for B27 in ankylosing spondylitis. Products of both HLA and non-HLA gene families may interact with infectious disease pathogens in susceptible individuals to produce a disorder which may not be specific in its association with any one pathogenic factor.
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PMID:Molecular variants of the HLA-B27 antigen in healthy individuals and patients with spondylarthropathies. 241 52

T-cell subpopulations and natural killer (NK) cells from peripheral blood, synovial fluid and synovial membranes from patients with seronegative spondyloarthropathies were investigated. Thirty-four patients with ankylosing spondylitis, sixteen patients with psoriatic arthropathy and six patients with pauciarticular juvenile chronic arthritis were studied. All the patient groups had normal proportions of T4+ and T8+ cells as well as normal T4/T8 ratios in peripheral blood. In the synovial fluids the T4/T8 ratios were reduced in ankylosing spondylitis and psoriatic arthropathy (p less than 0.05). Although both the T4 and T8 subpopulations were reduced, the T4/T8 ratios in the synovial membranes of patients with these two disorders tended to be within the normal range of that of peripheral blood. Increased numbers of T-cells in the synovial fluid from patients with ankylosing spondylitis expressed class II MHC antigens. The natural killer cell activity was normal in peripheral blood and synovial fluids of patients with ankylosing spondylitis and psoriatic arthropathy while it tended to be reduced, although not significantly, in pauciarticular juvenile chronic arthritis. Synovial membranes were almost devoid of NK cell activity. The number of Leu 7+ cells were reduced in synovial fluid of patients with psoriatic arthropathy (p less than 0.04), but not as significantly as in the two other patient groups.
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PMID:Phenotypes and spontaneous cell cytotoxicity of mononuclear cells from patients with seronegative spondyloarthropathies: ankylosing spondylitis, psoriatic arthropathy and pauciarticular juvenile chronic arthritis--analysis of mononuclear cells from peripheral blood, synovial fluid and synovial membranes. 326 76

In man a number of diseases are associated with certain alleles of MHC antigens. The most pronounced example is ankylosing spondylitis, which is strongly associated with HLA-B27. As a first step towards a model system to study the basis of this association, transgenic mice were generated that showed cell surface expression of the HLA-B27 antigen biochemically indistinguishable from HLA-B27 antigen expressed on human cells. This result was obtained by crossing two independently derived strains of mice, one of which is transgenic for the HLA-B27 heavy chain gene, and the other carrying and expressing the human beta 2m gene. Examination of HLA-B27 and human beta 2m mRNA in various tissues shows the two genes to be expressed in a coordinate fashion. The mRNA levels follow those of endogenous H-2 Class I genes.
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PMID:Crosses of two independently derived transgenic mice demonstrate functional complementation of the genes encoding heavy (HLA-B27) and light (beta 2-microglobulin) chains of HLA class I antigens. 330 31

We studied 175 consecutive patients with ankylosing spondylitis (AS) to define the genetic characteristics of those patients who had associated acute anterior uveitis (AAU). The first 131 patients were tested for HLA antigens of the A and B loci, and the remaining 44 patients were typed only for HLA-B27. AAU was significantly more common in B27 positive patients, occurring in 40 of 144 B27 positive (27.7%) and in only 3 of 31 B27 negative patients (9.7%) (p less than 0.05). Among the B27 positive AS patients, AAU occurred in 24 of 68 patients (35%) who also possessed HLA-A2 and in only 5 of 35 patients (14%) who lacked A2 (p less than 0.025). An independent association of AAU with A2 could not be shown. In the absence of evidence of linkage disequilibrium between A2 and B27 in the general population, the data suggest that the presence of A2 in B27 positive AS patients enhances the risk of AAU above that associated with B27 alone, and that other MHC-linked genetic factors, in addition to B27, are associated with susceptibility to AAU in AS patients.
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PMID:Association of HLA-A2 with uveitis in HLA-B27 positive patients with ankylosing spondylitis. 719 16

Linkage analysis of HLA haplotypes, HLA-B27 subtypes, and a 9.2-kb PvuII B7 restriction fragment length polymorphism (RFLP) (shown previously to be associated with peripheral arthritis in ankylosing spondylitis [AS]) in 115 relatives from 12 multiplex spondyloarthropathy (SNSA) and 2 B27-positive control families showed AS to be linked to HLA-B27 haplotypes. The RFLP segregated with HLA-A3- and HLA-A9-bearing haplotypes (lod score, 10.98; odds in favor of linkage, 9.2 x 10(10):1), although its linkage to AS or other SNSA per se was not seen. The association of HLA-A3/A9 with the RFLP was also seen in 52 AS patients and 92 controls, although no HLA-A, -B, -C, or -DR allele (other than HLA-B27) was significantly increased in frequency. The HLA-B27 subtype seen on all but one of the haplotypes studied was B*2705, the sole exception being HLA-B*2702. Although not ruling out a second HLA-A-linked gene influencing the clinical expression of AS, these data fail to support the role of a second MHC-associated gene in the pathogenesis of AS per se.
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PMID:HLA in ankylosing spondylitis: is HLA-B27 the only MHC gene involved in disease pathogenesis? 791 56

Superantigens are thought to play a role in acute infections and in the pathogenesis of autoimmune diseases that are believed to have an infectious etiology. The effect of the superantigens staphylococcal enterotoxin A, staphylococcal enterotoxin B, and streptococcal M type 5 protein on T cells derived from inflammatory tissues and peripheral blood (PB) of arthritis patients was studied in seven rheumatoid arthritis (RA), two psoriatic arthritis, two reactive arthritis, and one ankylosing spondylitis patient. Superantigen-reactive T cells and T cell lines derived from the PB, synovial fluid (SF), and synovial membrane (SM) of all 12 arthritis tissues recognized the superantigens in an MHC-unrestricted manner. Heterogeneities in proliferation and superantigen-directed T cell cytotoxicity were observed in E+ T cells and the T cell lines. Four SF-CD4+ mycobacteria heat-shock protein 65-kDa specific T cell clones generated from an RA patient could recognize and lyse each other when pulsed with staphylococcal enterotoxin A and used as targets. From another RA patient, four SF-CD4+ T cell clones that specifically recognize autoantigens were generated with human IgG fragments or collagen type II fragments. Heterogeneities of such superantigen-mediated specific lysis were also demonstrated. The data presented by us suggest a model in which superantigens do not have to be involved in triggering the initial disease because autoreactive T cells elicited by antigen can, in the presence of superantigen, lyse cells that express MHC class II molecules, including activated T cells.
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PMID:Superantigen-mediated proliferation and cytotoxicity of T cells isolated from the inflammatory tissues and peripheral blood of arthritis patients. 863 87


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