Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The three-dimensional structure of the HLA class I molecules has highlighted the importance of the "groove" formed by the helices. We used site-directed mutagenesis to construct a series of HLA-B27 mutants with different substitutions at the sites of the conserved amino acid residues of HLA-B27 subtypes, specifically residue 77 which is thought to be critical to the binding site of the molecule, and a residue at the CD8 binding site. We formed an anti-B27 CTL line and derived six anti-B27 clones. Each of the six clones showed a different pattern of reaction, reflecting the diversity of the epitopes recognized. All nine mutants were effective in altering allorecognition by HLA-B27 specific CTL, although positions 45 and 77 caused the most drastic effect. The residue in position 77 is also the last amino acid of the peptide sequence shared with Klebsiella. Our results highlight the importance of certain epitopes in allorecognition that may have important implications for the immunotherapy of autoimmune diseases.
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PMID:Effect of the substitution of critical residues on the allorecognition of HLA-B27. 128 53

Many human diseases are associated with HLA class I, class II and class III antigens. It appears that the class III antigen disease associations can be explained by a direct defect operating at the level of either the class III gene or its gene product. The mechanism underlying class I and class II antigen disease associations is at present unknown. In this review we have considered thirty diseases which have been ranked according to their relative risk as defined by the frequency of a given HLA antigen in patient and control populations. The chronic inflammatory disorder, ankylosing spondylitis and its association with HLA B27 has been used as a model to study the HLA linked diseases. We have suggested that the disease may be caused by the Gram-negative microorganism Klebsiella which has antigenic similarity to HLA B27. It is proposed that some antibodies made against Klebsiella bind to HLA B27, thereby acting as autoantibodies leading to the pathological sequelae of chronic inflammatory arthritis. This is the crosstolerance hypothesis or molecular mimicry model and it has been compared to the receptor model. It is further suggested that the crosstolerance hypothesis can be utilised as a general theory to explain the association of other diseases with the class I and class II antigens, and offer a possible explanation for the polymorphism of HLA.
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PMID:HLA and disease. 128 96

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the sacroiliac joints and vertebral column of unknown aetiology, but strongly related to the presence of the HLA-B27 antigen. The participation of bacterial infections as triggering factors have also been suggested. We have associated the 60 kDa heat shock protein of Klebsiella pneumoniae (HSP60Kp) with AS since we have previously demonstrated that most of the patients have IgG antibodies and active T cells that recognize preferentially this protein, but we have not yet identified the epitopes involved in the recognition. In order to know the amino acid sequence of HSP60Kp, and to be able to analyse in the future the relevant epitopes; we amplified by PCR and cloned the gene coding for this protein into the SmaI site of pUC19. The nucleotide sequence of the gene was obtained by the Sanger method using both manual and automatic techniques. Amino acid sequence of the HSP60Kp was deduced by translating the nucleotide sequence of the gene. The antigenic analysis of this sequence was compared to the antigenic analysis of the reported sequences of Escherichia coli GroEL and Yersinia enterocolitica HSP60. Using a software to predict HLA class I motifs, the nonapeptide (KRGIDKAVL) residues 117-125 of HSP60Kp showed a much higher affinity for HLA-B27 than the similar nonapeptide of E. coli GroEL and Y. enterocolitica HSP60. The only difference between the three peptides was in position nine. This finding could explain the association of AS only with the HSP60 of Klebsiella pneumoniae. On the other hand, hydrophilicity analysis, which indicates B cell epitopes, showed three similar strongly antigenic regions in the three proteins.
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PMID:Cloning and sequencing of the gene that codes for the Klebsiella pneumoniae GroEL-like protein associated with ankylosing spondylitis. 970 46