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)

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

The influence of assay conditions on anti-DNA determinations by an enzyme-linked immunosorbent assay (ELISA) was investigated to evaluate the detection of various DNA antigenic specificities. Among 4 monoclonal anti-DNA antibodies of MRL-lpr/lpr strain origin, 2 showed higher titers in 100 mM NaCl-50 mM Tris, pH 7.5 (Tris-NaCl) than in phosphate-buffered saline (PBS). The determination of 'polyspecificity' for these monoclonal products also depended on the set of conditions used for assay with inhibitory activity of polynucleotides differing in the 2 buffers. The buffer effects were not confined to the monoclonal antibodies as increases in anti-DNA titers were demonstrated for certain SLE patient sera when assayed in Tris-NaCl rather than PBS; sera of MRL-lpr/lpr mice showed an opposite effect, however, with enhancement of anti-DNA activity by PBS. These results suggest that the representation of antigenic sites on DNA may be variably affected by the conditions of assay, altering quantitative and qualitative assessment of this important serological marker.
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PMID:Influence of assay conditions on ELISA determinations of anti-DNA antibodies. 620 37

A simple and rapid microenzyme-linked immunosorbent assay has been developed for determination of anti-poly(ADP-ribose) antibodies in humans using a combination of protein A-alkaline phosphatase conjugates and poly(ADP-ribose)-coated polyvinyl microplates. After a 1-h treatment of the plates with 100 microliters of poly L-lysine (PLL) solution (50 micrograms/ml), an aliquot of the solution containing 100 ng poly(ADP-ribose) (50 microliters) was added to the PLL-treated plates and evaporated at 37 degrees C overnight to facilitate the adherence of poly(ADP-ribose) to the plates. Nonspecific binding of diluted test sera from patients with systemic lupus erythematosus (SLE) or from normal individuals to the PLL-coated plates was minimized by exposure of the plates for 1 h to Tris-buffered saline (pH 7.4) containing 0.01% bovine serum albumin (BSA). This method was also applicable to the determination of anti-double-stranded DNA antibodies in humans. The present assay is advantageous over those reported so far as it saves time and antigen.
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PMID:A simple and rapid microenzyme-linked immunosorbent assay for antibodies to poly(ADP-ribose) in systemic lupus erythematosus. 714 14

Recent studies have suggested that the lupus anticoagulant (LA) may be specific for prothrombin, prothrombin-phospholipid complexes, or beta 2 glycoprotein 1 (beta 2GP1) rather than phospholipids. We performed a series of experiments to determine whether LA is indeed phospholipid specific. IgG was purified from sera of six patients with the antiphospholipid syndrome (APS) and 10 healthy controls. The six IgG-APS preparations had both LA and anticardiolipin (aCL) activity. Incubation of the six IgG-APS preparations with cardiolipin (CL), phosphatidylserine (PS), phosphatidylcholine (PC), or PS/PC (20:80) liposomes in Tris-buffered saline, resulted in loss of LA activity from the supernatant. We postulated that loss of activity might have resulted from absorption of IgG LA antibodies by phospholipids, a dilutional effect, or the presence of phospholipids in the supernatant causing 'by-pass' of IgG LA inhibitory activity. To distinguish between these possibilities, we re-isolated IgG from the supernatants and re-tested them for LA activity. IgG re-isolated from the PS. CL and PS/PC supernatants had no LA activity, but LA activity remained in the PC supernatant. This suggested that IgG with LA activity was absorbed by negatively charged but not by zwitterionic phospholipids. In like manner, PS, CL and PS/PC, but not PC liposomes, absorbed IgG with aCL activity. Mixtures of the phospholipid liposomes with beta 2GP1 did not modify the absorption of IgG with LA or aCL activity. Finally, we demonstrated that IgG eluted from immunoglobulin-cardiolipin liposome complexes had LA activity. Based on these findings, we conclude that at least one population of antibodies with LA activity is phospholipid specific.
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PMID:Are immunoglobulins with lupus anticoagulant activity specific for phospholipids? 825 79

The aim of this study was to prepare a DNA immunoadsorbent for the specific, extracorporeal removal of anti-DNA antibodies from the blood of patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Two kinds of cellulose beads were applied as a carrier. Calf thymus DNA was covalently coupled to the carrier using the epichlorohydrin method. Efforts were focused on optimization of conditions for activation and coupling, trying to couple as much DNA as possible to a certain amount of carrier. It was found that the activation level increased with the increase of NaOH concentration and the amount of epichlorohydrin used. The mole of epichlorohydrin must be in excess of that of NaOH because excess NaOH could react further with the epoxy groups in the beads resulting in a decrease of activation level. High activation level could be obtained in a medium of 3.0 M NaOH. The DNA coupling was found to be mainly temperature and pH dependent. Using 0.1 M Tris-HCl buffer, pH 8 at a temperature of 50-90 degrees C, more than 3 mg of DNA could be coupled to 1 ml of wet beads. Prolonging the coupling reaction under 50 degrees C to 72 h resulted in the same coupling capacity as that obtained under 90 degrees C. To evaluate the adsorption ability for anti-DNA of this immunoadsorbent, batch and circulation tests were applied using SLE patient plasma. The immunoadsorbents showed excellent adsorption capacity, especially the cellulose with smaller size (200-300 microm). The incubation of 20 ml of patient's plasma with 1 ml of adsorbent resulted in an 80% decline in the anti-DNA antibody level. In the circulation tests, 30 ml of plasma was circulated through a column containing 3 ml of adsorbent. The maximum decline in anti-DNA level, 80%, was obtained after 60 min. Such high adsorption capacity and high adsorption rate suggest this immunoadsorbent may be used for treatment. For comparison, 1,4-butanediol diglycidyl ether activation method and other DNA sources were tested with the same protocol.
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PMID:Development of cellulose-DNA immunoadsorbent. 1187 50

Calreticulin has been reported to be an autoantigen in various autoimmune connective tissue diseases and in coeliac disease. Previous studies have used incubation buffers with low salt and low detergent concentrations (low stringency conditions) with serum albumin or other proteins as a blocking agent. Using these conditions we found a relatively high level of non-specific binding in many sera. Antibodies to proteins that are used as blocking reagents in ELISA (bovine serum albumin (BSA), ovalbumin, skimmed milk powder) are frequently present in sera, and these may cause false-positive results. Moreover, the low isoelectric point of calreticulin and its chaperone properties may give rise to false-positive results under low stringency conditions. We report that the use of a simple buffer without protein (50 mM Tris, pH 7.5, 1% Tween 20, 0.3 M NaCl) removes most of the problems with unwanted binding (high stringency conditions). Using the high stringency conditions, we screened sera from 107 patients with systemic lupus erythematosus, sera from patients with other systemic autoimmune diseases and from children with coeliac disease for the presence of high-affinity calreticulin autoantibodies by immunoblotting and ELISA. None of the sera contained high-affinity calreticulin antibodies. It is concluded that calreticulin is not a common autoantigen in patients with autoimmune connective tissue diseases or coeliac disease.
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PMID:Absence of high-affinity calreticulin autoantibodies in patients with systemic rheumatic diseases and coeliac disease. 1608 63

The objective of this study was to compare the effects of dimethylformamide (DMF) and glycerol in canine (Canis lupus familiaris) semen cryopreservation based on postthaw motility and velocity evaluated by computer-assisted sperm analysis (CASA) and the effects on subjective progressive motility, percentage of live sperm, and plasma membrane functional integrity. The semen was diluted in two steps with an egg-yolk Tris extender containing 6% glycerol or DMF, frozen in 0.25-mL straws, and stored in liquid nitrogen. Immediately after thawing, samples were accessed for subjective sperm motility, sperm membrane functional integrity, percentage of live sperm, and evaluation by CASA. There were differences (P<0.05) between glycerol and DMF with regard to subjective progressive motility (43.1% vs. 21.5%), objective progressive motility (11.8% vs. 6.2%), velocity average pathway (31.1 vs. 23.1 microm/sec), and amplitude of lateral head (3.3 vs. 3.9 microm), which confirmed the efficiency of glycerol. In conclusion, objective analysis performed by CASA confirmed that no benefits were derived by using DMF to replace glycerol for cryopreservation of canine semen.
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PMID:Dimethylformamide is no better than glycerol for cryopreservation of canine semen. 1954 62