Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anti-DNA antibodies have been successfully induced in normal, nonautoimmune mice by immunization with complexes formed with a DNA-binding peptide, Fus1, and native, B form, mammalian DNA. Fus1 is a 27-amino acid peptide from the internal domain of a ubiquitin fusion protein from Trypanosoma cruzi. The structure of this peptide is homologous to the consensus amino acid sequence for a DNA-binding, "zinc finger" motif, and the peptide binds to DNA. A panel of six anti-DNA antibody-producing hybridomas, two IgM and four IgG2a, have been generated from a single BALB/c mouse immunized with Fus1-DNA. The V region structures for both H and L chains of the induced anti-DNA antibodies are highly homologous if not identical to the V region structures of spontaneous anti-DNA antibodies from autoimmune (NZB x NZW)F1 mice. The DNA specificities of the anti-DNA antibodies were also similar to those of autoimmune anti-DNA antibodies. Three of the four induced IgG antibodies bound equally well to native and denatured DNA. These results demonstrate that antibody specific for nDNA can be induced with immunogenic complexes of native DNA. They also demonstrate that monoclonal representatives of the induced anti-DNA antibodies have serologic and structural characteristics similar if not identical to those of spontaneous anti-DNA antibodies from autoimmune mice. The experimental system described here should provide insight not only about the structural basis for autoimmunity to DNA but also the function of anti-DNA antibody in the immunopathology of SLE.
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PMID:Structural similarity of antibody variable regions from immune and autoimmune anti-DNA antibodies. 849 96

We identified HLA-DRB1*0901-binding peptides by affinity-based selection of a phage random peptide library using the biotinylated DR9 complex. Analogue peptides with single amino acid residue substitutions of a DR9 binder revealed that two major anchors (WxxS, where x is any amino acid) play an essential role in binding to DR9. Determination of the binding affinity of synthetic wild-type-based analogue peptides showed that substituting W to F or L, and S to A, V, or F allow high affinity binding with DR9. Collectively, DR9-binding peptide motifs identified in this study are characteristic in that (a) only two anchors of the NH2-terminal half of binding peptides play important roles in binding, and (b) small neutral hydrophilic Ser is allowed as the second anchor for high-affinity binding, unlike the other DR-binding motifs heretofore reported. The implications of our results are discussed in light of the HLA-DR9-associated susceptibility to juvenile-onset myasthenia gravis and systemic lupus erythematosus with antiphospholipid syndrome, in particular, T-cell responses to autoantigens.
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PMID:Identification of HLA-DR9 (DRB1*0901)-binding peptide motifs using a phage fUSE5 random peptide library. 888 11

The hydrophobicity of short synthetic peptides of 5-10 residues was enhanced for high coating efficiency as antigens in indirect ELISA. To obtain enhanced hydrophobicity, coupling of epsilon-aminocaproic acids to the synthetic peptides was carried out during solid phase peptide synthesis. As a short peptide model, three analogues of a streptavidin binding peptide consisting of 5 amino acid residues were prepared with four epsilon-aminocaproic acid residues. HPLC analysis showed a dramatic increase in hydrophobicity after modification and the modified peptides showed a better adsorption ability than the unmodified peptides in indirect ELISA. The whole process from antigen coating to color development was carried out within 2.5 to 3 h by dissolving the peptide in methyl alcohol and evaporating the solvent in each well of the microplate. As an application of this method, a peptide assumed to function as one of the epitopes of the human 60 kDa Ro/SSA antigen was selected from hydrophilicity, acrophilicity and hydropathy plots. The peptide was synthesized having an epsilon-aminocaproic acid modification at both N and C terminal ends and was tested with 30 sera from patients with systemic lupus erythematosus (SLE), 20 normal sera and a standard anti-Ro/SSA serum. The ELISA results revealed that the method gave a high signal-to-background ratio without altering the specificity of the assay. Moreover, our process was far simpler and more rapid than conventional methods used in indirect ELISA. Thus this method could be useful in the development of techniques for the diagnosis of SLE.
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PMID:Modification of short peptides using epsilon-aminocaproic acid for improved coating efficiency in indirect enzyme-linked immunosorbent assays (ELISA). 943 69

Immunization of mice with beta2 glycoprotein I (beta2GPI) and also with GDKV, a synthetic peptide representing the phospholipid (PL)-binding site of beta2GPI, induced pathogenic aPL antibodies that bind and activate endothelial cells, enhanced thrombus formation and caused fetal death in pregnant mice. TIFI is a PL-binding peptide spanning the Thr101-Thr120 of ulb0-hcmva from human cytomegalovirus (CMV), which shares structural similarity with the PL-binding site of beta2GPI. Immunization with this peptide induced pathogenic aPL and anti-beta2GPI antibodies in mice. These antibodies activated endothelial cells and enhanced thrombus formation in vivo, but whether these antibodies cause fetal death in mice is not known. The objective of this study was to examine the effects of these antibodies on pregnancy outcome in mice. Two groups of pregnant BALB/c mice were injected with either hybridoma supernatant containing D3/AC10, a CMV-peptide-induced monoclonal aPL, at days four, eight and 12 of the pregnancy, 100 microg per mouse (study group) or with culture media alone (control group). The litter size was significantly smaller in the study group (4.80 +/- 1.15 versus 7.28 +/- 0.18, t = - 2.526, P < 0.03). In conclusion, aPL induced by CMV peptides may have pathogenic properties similar to human autoimmune aPL. These findings further support the hypothesis that at least in some patients with APS, pathogenic aPL antibodies may be generated by immunization with CMV products during incidental exposure to the virus via a molecular mimicry mechanism.
Lupus 2004
PMID:Intrauterine fetal death in mice caused by cytomegalovirus-derived peptide induced aPL antibodies. 1487 Sep 13

Antigen-specific CD8+T lymphocytes play an important role in defense against cutaneous microbial infection and skin cancer as well as in the pathophysiology of autoimmune skin disease such as lupus erythematodes and vitiligo. We have explored the role of CD8+ cytotoxic T lymphocytes (CTL) in an experimental mouse model of vitiligo, a pigmentation disorder characterized by focal loss of melanocytes in the skin. Using genetic immunization techniques we found that pigment cells in the epidermis can be destroyed by CD8+ T cells specifically recognizing a single H2-Kb-binding peptide derived from the model melanocytic self antigen tyrosinase-related protein 2 (TRP2), a melanosomal enzyme involved in pigment synthesis. Experimental evidence suggests that peripheral tolerance of pigment cell-specific cytotoxic CD8+T cells is regulated in two steps. In the induction phase, stimulation and expansion of these T cells in vivo strictly depends on CD4+ T cell help. In the effector phase, autoimmune destruction of melanocytes in the skin depends on local inflammation facilitating the migration of T cells into the epidermis and supporting effector functions. Our results suggest that accidental stimulation of CD8+ CTL recognizing MHC class I-binding peptides derived from melanocytic proteins in the context of an inflammatory skin disease may play an important role in the pathophysiology of vitiligo. Further investigations will address the role of chemokines, chemokine receptors and adhesion molecules in this experimental system and will reveal the role of keratinocytes and Langerhans cells in regulating cutaneous CD8+ T cell responses.
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PMID:Initiation and regulation of CD8+T cells recognizing melanocytic antigens in the epidermis: implications for the pathophysiology of vitiligo. 1567 23

In the present study plasma samples from 15 systemic lupus erythematosus (SLE) patients and 16 healthy controls of initially unknown haptoglobin (Hp) phenotype were separated by 2-DE, and tryptic digests of the excised Hpalpha polypeptide chain spots were analyzed by MALDI-TOF-MS. Selected tryptic peptides were sequenced by nano-(n)ESI-IT MS/MS. The six major Hp phenotypes were present, although with distinct frequencies in controls and SLE patients. Thus, there were an increased proportion of SLE patients with Hp 2-2, or Hp 2-1S phenotypes. The Hp phenotype distribution resulted in allele frequencies of 0 625 (Hp(2)), 0.281 (Hp(1S)), and 0.093 (Hp(1F)) in healthy controls, correlating fairly well with the allele frequencies of European populations. In contrast, the Hp allele frequencies of the SLE patients were 0.733 (Hp(2)), 0.233 (Hp(1S)), and 0.033 (Hp1(1F)), which clearly indicated an increased frequency of Hp(2), a similar proportion of Hp(1S) and a diminished proportion of Hp(1F) in SLE patients compared with that in healthy controls. Preferential Hpalpha2 expression in SLE patients may contribute to some of the clinical manifestations of the disease such as hypergammaglobulinemia, systemic vasculitis, and cardiovascular disorders.
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PMID:Proteomic analysis of plasma from patients with systemic lupus erythematosus: increased presence of haptoglobin alpha2 polypeptide chains over the alpha1 isoforms. 1654 81