Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0409974 (lupus)
 22,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 96-well microplate ELISA for the detection of antibodies to DNA is described. A number of buffers and precoating treatments were used to evaluate the optimal method for coating the plate with DNA. These included pretreatment of the plates with poly-L-lysine or protamine sulfate, and posttreatment with glutaraldehyde, none of which improved the performance of the assay. Whereas bicarbonate and borate coating buffers gave equivalent and satisfactory results, TRIS buffer resulted in very high binding of immunoglobulin to wells not coated with antigen. Sera from groups of patients with autoimmune disease as well as normal sera were tested against plates optimally coated with native E. coli DNA, calf thymus DNA, and heat-denatured DNA. Using native E. coli DNA, virtually none of 35 normal sera had any detectable antibody. With this antigen, as well as with native calf thymus DNA, significant levels of DNA antibody were found only in SLE patients. Most patients with SLE or drug-induced lupus, as well as some patients with rheumatoid arthritis and normal individuals had antibodies that bound to heat-denatured (single-stranded) DNA. Using either native E. coli or calf thymus DNA, a good correlation was found between the amount of DNA antibody detected by ELISA and the Farr-type radioimmunoassay.
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PMID:Microplate ELISA for detection of antibodies to DNA in patients with systemic lupus erythematosus: specificity and correlation with Farr radioimmunoassay. 217 99

Pretreatment of polystyrene microplate wells with certain doses of UV light enhances their capacity for binding to single-stranded DNA, double stranded DNA and various synthetic polynucleotides. The use of UV-irradiated plates to immobilize nucleic acid antigens provides a simple, rapid, and specific ELISA for measuring anti-nucleic acid antibodies. The assay is at least as sensitive as the more complex method of precoating plates with poly(L-lysine). It is useful for detection of anti-DNA antibodies in sera of systemic lupus erythematous patients, as well as in culture fluids of murine and human anti-DNA-secreting hybridomas.
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PMID:A rapid ELISA for measurement of antibodies to nucleic acid antigens using UV-treated polystyrene microplates. 348 20

By studying antinuclear antibody production at the cellular level, we can better understand the problems of immunoregulation in individuals with systemic lupus erythematosus. To date, the use of hemolytic plaque assays to detect B cells secreting antinuclear antibodies has been hampered by an inability to achieve reliable coating of red cells by nuclear antigens. Because the chromic chloride technique has proved ineffective for coupling nucleic acids and/or nuclear antigens to sheep red blood cells (SRBC) in our laboratory, we have developed a method of coupling SS DNA, DS DNA, poly(I).poly(C), Sm, and ENA to red cells pretreated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (ECDI) and poly(L-lysine) (PLL). Coated red cells were agglutinated by specific antisera and not by normal sera and were then used in hemolytic plaque assays to detect antinuclear plaque-forming cells (PFC) in spleens from various strains of mice with lupus-like syndromes. PFC specific for SS DNA, DS DNA, poly(I).poly(C), Sm, and ENA were found in MRL/lpr and NZB x W mice, and the number of anti-SS DNA and anti-DS DNA PFC correlated with the age of the animals. Indirect (IgG) PFC specific for nuclear antigens increased dramatically in female NZB x W mice between 11 and 13 months, a time when more than 50% of the animals usually die. Preliminary studies have shown that PFC specific for nuclear antigens can be detected in peripheral blood from patients with lupus erythematosus. Pretreatment of sheep red cells with ECDI and PLL thus allowed the coupling of selected nuclear antigens to these cells and provided the first demonstration of IgM and IgG PFC specific for a variety of nuclear antigens.
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PMID:Use of nuclear antigen-coated red cells in hemolytic plaque assays. 633 24

Heparan sulphate-reactive antibodies in lupus sera have been suggested to be anti-DNA-DNA/histone immune complexes and to be associated with lupus nephritis. In this study, 23 anti-DNA-positive lupus sera including 13 active nephritis sera were tested for the presence of circulating anti-DNA-DNA/histone immune complexes by solid phase heparan sulphate-ELISA. Because of high background binding to protamine chloride-linked heparan sulphate plates, poly-L-lysine (PLL) was used as a linker and the remaining active sites of PLL were blocked with poly-L-glutamic acid. The ELISA was capable of detecting small amounts of anti-DNA IgG-DNA/histone immune complexes formed in vitro. However, only three active nephritis sera of the 23 sera tested showed significant binding to heparan sulphate plates. This binding was found to be non-specific, the result of high background binding of IgG to PLL. Anti-heparan sulphate ELISA using positively charged linkers detects non-specific binding when lupus sera are tested. Specific assays need to be developed for DNA/histone-related immune complexes present in lupus sera.
Lupus 1995 Feb
PMID:Heparan sulphate-ELISA gives false positive results for anti-DNA-DNA/histone immune complexes in sera of patients with SLE. 753 23

Malondialdehyde (MDA), a peroxidative end-product released during polyunsaturated fatty acid degradation, reacts strongly with lysine residues of cellular proteins. MDA-modified proteins become immunogenic and may elicit specific autoantibody formation. We hypothesized that systemic diseases in which inflammatory events occur, could be an interesting model for studying oxidative stress. A few studies have suggested that MDA-modified proteins may exist in systemic diseases, and that autoantibodies to MDA-modified structures might reflect this oxidative process. Autoantibodies to MDA-modified epitope(s) were therefore assayed in sera of patients with systemic lupus erythematosus (SLE, n = 29), scleroderma (SCL, n = 11), giant cell arteritis (GCA, n = 11), periarteritis nodosa (PAN, n = 10), rheumatoid arthritis (RA, n = 9), and healthy subjects (HS, n = 32). Significantly increased anti-MDA-modified epitope(s) autoantibodies were found in patients with SLE and also in other systemic diseases such as PAN and SCL. Autoantibodies to MDA-modified epitope(s) were predominantly of IgM isotype, with low levels of IgG and no IgA activity. In SLE, anti-MDA-modified epitope(s) autoantibody titres correlated strongly with systemic lupus activity measure (SLAM, r = 0.702, P = 0.0001), anti-nuclear antigen autoantibodies (ANA, r = 0.4, P = 0.029), IgG anti-cardiolipin (r = 0.558, P = 0.03) and the steroid drug regimen (r = 0.52, P = 0.004). Autoantibodies to MDA-modified epitope(s) may reflect oxidative modifications occurring in systemic diseases, and might be useful as clinical markers of SLE activity if further investigated.
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PMID:Autoantibodies to malondialdehyde-modified epitope in connective tissue diseases and vasculitides. 754 46

Naturally occurring polyreactive anti-DNA mAbs derived from a nonimmunized (NZB x NZW)F1 mouse with spontaneous lupus erythematosus penetrated and accumulated in the nuclei of a variety of cultured cells. These mAbs and their F(ab')2 and Fab' fragments, covalently coupled to fluorescein, peroxidase, or a 15-mer polynucleotide, also translocated to the cell nuclei. A 30-amino acid peptide corresponding to the combined sequences of the complementary-determining regions 2 and 3 of the heavy chain variable region of one mAb was able to penetrate into the cytoplasm and nucleus of cells of several lines. This peptide recognized DNA and was strongly polyreactive. Streptavidin-peroxidase conjugates complexed with the N-biotinylated peptide were rapidly translocated into cells. Similarly, peroxidase or anti-peroxidase polyclonal antibodies covalently coupled to the N-cysteinylated peptide through an heterobifunctional maleimide cross-linker were also rapidly internalized and frequently accumulated in nuclei. The peptide carrying 19 lysine residues at its N-terminal was highly effective in transfecting 3T3 cells with a plasmid containing the luciferase gene. Thus, penetrating mAbs and derived peptides are versatile vectors for the intracellular delivery of proteins and genes.
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PMID:Polyreactive anti-DNA monoclonal antibodies and a derived peptide as vectors for the intracytoplasmic and intranuclear translocation of macromolecules. 957 29

An experimental model of systemic lupus erythematosus has recently been described in normal animals. We sought to confirm and extend this model, which involved immunization of normal rabbits and mice with a peptide of Sm B/B', PPPGMRPP. This peptide is an early target of the immune response in anti-Sm-positive patients with lupus. The peptide was used in a multiple Ag peptide format, with multiple copies of PPPGMRPP bound to an inert lysine backbone. New Zealand White rabbits and A/J and C57BL/10ScSn mouse strains were immunized with PPPGMRPP-MAP. Pepscan assays were used to determine the epitope spreading of the anti-PPPGMRPP-MAP response to other octamers of SmB/B' following immunization. We obtained high titer anti-PPPGMRPP-MAP IgG responses in the New Zealand White rabbits and A/J mice. The rabbits immunized with PPPGMRPP-MAP showed varying degrees of epitope spreading, while the A/J mice showed no spreading. We observed no autoantibodies to dsDNA or other anti-nuclear autoantibodies in our animals by ELISA or immunofluorescence, although anti-nuclear autoantibodies were found by Western blotting in some of the rabbits. No evidence of clinical disease was seen in our normal animals. These data underline the difficulties often associated with the reproduction of animal models in different laboratories.
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PMID:Immunization with a peptide of Sm B/B' results in limited epitope spreading but not autoimmune disease. 1022 79

To be positively selected, immature thymocytes must receive signaling through their T-cell receptor (TCR), and engagement of relatively low-affinity self-peptides permits further T-cell maturation. However, mature T cells no longer overtly respond to such low-affinity antigens, indicating that T cells acquire a higher threshold for activation during thymopoiesis. We wondered whether partial interference in positive selection could produce T cells that respond to the selecting self-peptide. This possibility was tested by injecting procainamide-hydroxylamine (PAHA), a lupus-inducing drug, into the thymus of adult normal mice. Three weeks after the second injection, IgG antichromatin antibodies appeared in the circulation and remained for several months. The murine antichromatin antibodies reacted with the (H2A-H2B)-DNA subnucleosome complex, the predominant specificity in patients with procainamide-induced lupus. In thymus organ and reaggregate cultures, PAHA had no effect on negative selection of T cells with high affinity for a co-present antigen, but acted on CD4+ CD8+ immature T cells as they underwent positive selection. TCR transgenic T cells specific to cytochrome c peptide 88-104 acquired the capacity to respond to the low-affinity analogue at position 99 (lys-->ala) if PAHA was present during their development. PAHA also blocked the capacity of a T-cell line to become anergic after anti-CD3 treatment, suggesting that PAHA prevents the production of negative regulators that accumulate in response to partial signaling through the TCR. These results are consistent with the view that T cells acquire self-tolerance during positive selection, and disruption of this process can result in autoreactive T cells and systemic autoimmunity.
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PMID:A nondeletional mechanism for central T-cell tolerance. 1164 11

Sequence analysis of anti-DNA antibodies is important in determining the molecular features which distinguish potentially pathogenic antibodies from those which are less likely to be pathogenic. Previous analysis of murine anti-DNA antibody sequences suggested that particular murine immunoglobulin genes are used preferentially to encode such antibodies and that somatic mutations to arginine, asparagine and lysine may be important in the creation of DNA binding sites. In this paper, a systematic analysis of published human anti-DNA sequences shows no strong evidence for preferential usage of particular human V(H) or V(L) genes in anti-DNA antibodies. Somatic mutations in IgG and IgA antibodies are clustered in the complementarity determining regions (CDRs) due to the effect of antigen drive. This process contributes to an excess of arginine, asparagine and lysine residues in these CDRs, some of which are likely to play an important role in binding to DNA. Computer modeling and in-vitro expression experiments are likely to help define the roles played by these residues in antigen binding and pathogenicity more clearly.
Lupus 2002
PMID:Systematic analysis of sequences of anti-DNA antibodies--relevance to theories of origin and pathogenicity. 1252 46

Anti-DNA antibodies contribute to the pathology of systemic lupus erythematosus. Their depositon in tissue lesions could result from localization of preformed immune complexes of antibodies with DNA or nucleosomes, or from cross-reaction of anti-DNA antibodies directly with tissue proteins. Structural analyses contribute to understanding their pathogenic potential. Primary structures of lupus immunoglobulin G double-stranded DNA-binding autoantibodies are determined by immunoglobulin genes with mutated variable region segments, indicative of selection by immunizing antigen. Arginine, lysine and asparagine residues in complementarity-determining region favor DNA binding. Heavy-chain variable regions make major contributions to DNA binding; affinity and specificity of binding are modulated or can be abrogated by the light-chain variable domain. Crytallographic structure is known for a few antibody-DNA complexes and several ligand-free Fab fragments. Computer modeling supplements this limited information. Structural information of lupus antibody interactions with both DNA and cross-reacting molecules will support use of ligands to inhibit tissue deposition of the antibodies and prevent lesion formation in lupus.
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PMID:Anti-DNA antibodies: aspects of structure and pathogenicity. 1267 96


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