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Biomedical subjects

R L Rubin

Publications and source records attributed to R L Rubin.

At least 55 records · Page 3Linked to original sources
PubMed1992

Autoantibodies associated with lupus induced by diverse drugs target a similar epitope in the (H2A-H2B)-DNA complex.

IgG reactivity with the (H2A-H2B)-DNA complex, a subunit of the nucleosome, has been detected in many patients with lupus induced by procainamide and quinidine, but the similarity among the epitopes targeted by these antibodies in this heterogeneous patient group as well as the prevalence of this specificity in lupus induced by other drugs is unknown. Studies with histone-DNA complexes formed by sequential addition on a solid phase demonstrated that complexes containing single histones had negligible antigenicity, indicating that DNA stabilizes a protein epitope in the H2A-H2B dimer or that the complete epitope is generated by a surface feature involving H2A-H2B and DNA. F(ab')2 isolated from a patient with procainamide-induced lupus blocked greater than 90% of the anti-[(H2A-H2B)-DNA] reactivity in six of six sera from patients with lupus induced by procainamide, four of four quinidine-induced patients and in sera from patients with lupus induced by acebutolol, penicillamine, and isoniazid, but not methyldopa or auto-antibodies to the component macromolecules. Fab fragments purified from the IgG of two quinidine-induced lupus patients and patients with isoniazid- and procainamide-induced lupus retained 39% +/- 8% of their original IgG reactivity compared to 34 +/- 28% of the original anti-tetanus toxoid activity of Fab fragments in two of the same sera and two normal sera. These results indicate that anti-[(H2A-H2B)-DNA] does not require divalent antigen-antibody complexes for stability, and that the complete epitope is created by the monomeric, trimolecular histone-DNA complex. We conclude that despite their pharmacologic and chemical heterogeneity, many lupus-inducing drugs elicit near identical autoantibodies.

Antibodies, Antinuclear↗
PubMed1992

Anti-histone autoantibodies recognize centromeric heterochromatin in metaphase chromosomes and hidden epitopes in interphase cells.

IgM autoantibodies from a subset of patients with undifferentiated rheumatic disease syndromes stained mouse kidney nuclei with a distinctive variable large-speckled (VLS) indirect immunofluorescence (IIF) pattern. However, these antibodies did not stain nuclei of tissue culture cells prepared with conventional fixation. These sera were shown to react with histone H3 by an enzyme-linked immunosorbent assay (ELISA), and adsorption with H3 reduced or eliminated the IIF reaction. Sera yielding a VLS-IIF pattern reacted in ELISA with all three H3 variants as well as the native (H3-H4)2 tetramer, but the reactive determinants were unavailable for binding when chromatin was the substrate. By IIF assay, the epitopes were exposed after treatment of tissue culture cells with 0.5 M NaCl, and were removed by 1.5 M NaCl. These sera also stained the centromeric region of metaphase chromosomes. These observations suggest that the VLS-IIF pattern is due to antibodies that recognize epitopes on constitutive heterochromatin near the centromere. The epitopes are exposed in differentiated cells but hidden in dividing cells. Histone in heterochromatin, or CENP-A, a histone-like protein in the centromere with a sequence similarity to histone H3, are candidates for the target antigen.

Autoantibodies↗
PubMed1992

Drug induced systemic lupus erythematosus due to ophthalmic timolol.

We report a case of systemic lupus erythematosus (SLE) apparently induced by topical use of ophthalmic timolol maleate, a beta adrenergic blocking agent. The patient developed fever, malaise, pleurisy and recurrent sterile pleural effusions while taking no medication other than timolol. Antinuclear antibodies in a homogenous pattern, and markedly elevated histone antibodies (IgG anti-(H2A-H2B)-DNA) were present while antibodies to native DNA were absent. After discontinuation of the timolol, his symptoms improved promptly and the pleural effusions resolved. To our knowledge, this is the first report of timolol induced SLE.

Administration, Oral↗
PubMed1991

Autoantibodies to native myeloperoxidase in patients with pulmonary hemorrhage and acute renal failure.

Sera from 245 patients were screened by indirect immunofluorescence for perinuclear/nuclear staining (P-ANCA) of ethanol-fixed neutrophils, a staining pattern which is associated with the presence of antibodies to myeloperoxidase. Using immunoblot and immunoprecipitation techniques on 15 P-ANCA-positive sera, 13 patients demonstrated antibody to purified or native myeloperoxidase but not to denatured myeloperoxidase. In patients with P-ANCA, the most frequent reason for medical attention was hemoptysis (8/13; 62%). Of the 15 sera with P-ANCA, acute renal failure was identified in 9 patients (60%). Five patients (33%) had both. All patients (eight of eight) with hemoptysis had antibodies which bound functional MPO as compared to three of seven P-ANCA-positive patients without hemoptysis (P less than 0.001), suggesting that antibodies which recognize conformational sites on native myeloperoxidase occur in a subgroup of patients with alveolar hemorrhage as their presenting clinical sign. These findings may provide insight into the disease process associated with P-ANCA. We further identify a subgroup of patients with a severe pulmonorenal syndrome and antibodies recognizing native myeloperoxidase.

Acute Kidney Injury↗
PubMed1991

The genetic and biochemical basis of polyketide metabolism in microorganisms and its role in drug discovery and development.

The possibilities for the design of new drug screening and development strategies directed to a specific objective on the basis of genetic engineering of microorganisms is discussed from two points of view. Firstly, results of work on genetic hybrids of STREPTOMYCES species for the production of new metabolites such as mederrhodin (1) and aloespanoarin II (4) are described. Secondly, the enhanced production of known metabolites such as tetracenomycin A (2) (11) and tetracenomycin C (9) by recombinant STREPTOMYCES species is considered. Mechanistic aspects of polyketide metabolism are included.

Journal Article↗
PubMed1991

Drug-induced anti-histone autoantibodies display two patterns of reactivity with substructures of chromatin.

Increasing evidence suggests that autoantibodies in the rheumatic diseases are a consequence of immune selection by self-material, but the nature of the in vivo immunogen is unknown. Insight into this problem may be obtained by measuring autoantibody binding to various forms of a target antigen. Antihistone antibodies arising as a side effect of therapy with various drugs offer an opportunity to explore this premise because many forms of histone have been characterized and adapted to ELISA formats. Two patterns of antibody reactivity were observed. All 21 patients with symptomatic procainamide-induced lupus and 7 of 12 patients with quinidine-induced lupus had IgG antibodies reacting predominantly with the (H2A-H2B)-DNA complex and with chromatin. In contrast, antibodies in 19 of 24 patients taking procainamide without accompanying lupus-like symptoms did not show any pattern. The second pattern was observed in 18/19 chlorpromazine-treated patients and 14/17 patients with hydralazine-induced lupus in which IgM antibodies displayed more reactivity with DNA-free histones than with the corresponding histone-DNA complexes and almost no binding to H1-stripped chromatin. Absorption studies were entirely consistent with these results. Thus, the two patterns of reactivity with nucleosomal components reflect the molecular substructure of chromatin, suggesting that two processes underlie antihistone antibody induction by drugs. In one, IgG autoantibodies appear to be elicited by chromatin, whereas in the other, autoimmune tolerance to native chromatin appears largely intact, and IgM antibodies may be driven by DNA-free histone.

Autoantibodies↗
PubMed1991

The genetic and biochemical basis of polyketide metabolism in microorganisms and its role in drug discovery and development.

The possibilities for the design of new drug screening and development strategies directed to a specific objective on the basis of genetic engineering of microorganisms is discussed from two points of view. Firstly, results of work on genetic hybrids of Streptomyces species for the production of new metabolites such as mederrhodin (1) and aloespanoarin II (4) are described. Secondly, the enhanced production of known metabolites such as tetracenomycin A2 (11) and tetracenomycin C (9) by recombinant Streptomyces species is considered. Mechanistic aspects of polyketide metabolism are included.

Acetates↗
PubMed1990

Subnucleosome structures as substrates in enzyme-linked immunosorbent assays.

Histone preparations preserving the tertiary and quaternary structure of histone-histone complexes and histone-DNA complexes, as well as individual histones, were isolated or reconstituted. Various parameters were tested in order to determine the suitability of these complexes for use as substrates in enzyme-linked immunosorbent assays. The protein concentration required to saturate the solid phase was determined, and the amount of bound protein was quantified by the micro-bicinchoninic acid protein assay. In addition, the relative DNA content of solid phase antigen was measured by the binding of monoclonal anti-native DNA antibodies. Prototype sera representing different disease groups produced reproducible and unique patterns of reactivity on the panel of antigens, demonstrating the lack of substantial assay bias. Two substrates, the H2A-H2B dimer and the H2A-H2B-DNA complex, both appear to be oriented in a random manner on the solid phase, leaving a number of different epitopes exposed to the solution. This novel set of histone antigens can now be used to define the specificity of anti-histone antibodies in relation to the quaternary structure of chromatin.

Animals↗
PubMed1990

D-penicillamine-induced lupus erythematosus.

We describe a patient who presented with polyarthritis, pleurisy, rash, and a positive antinuclear antibody result after 5 years of D-penicillamine therapy. D-penicillamine-induced antinuclear antibodies were mainly high-titer IgG directed against the (H2A-H2B)-DNA complex. Weak IgM activity with H1 and H2B was also observed. Withdrawal of D-penicillamine therapy resulted in improvement in clinical symptoms and gradual resolution of serologic abnormalities.

Autoantibodies↗
PubMed1990

Pseudoautoimmunity in normal mice: anti-histone antibodies elicited by immunization versus induction during graft-versus-host reaction.

Native preparations of evolutionarily conserved intracellular macromolecules are generally nonimmunogenic when injected in soluble form. However, vigorous immune responses were observed when common autoantigens such as histones, DNA or Sm antigen, or homologous liver homogenate were noncovalently coupled to latex beads prior to injection into mice. Antibody response to histone beads displayed immunologic memory and required a functional thymus, suggesting that T-helper cells were involved. However, bead-elicited autoantibodies could be distinguished from true autoantibodies in that they reacted with denatured, minor, or foreign components of the preparations or to regions unexposed in the native form of the immunogen. This response contrasted with spontaneously arising autoantibodies accompanying graft-versus-host (GVH) disease in the same strain of mice which preferred native nucleoprotein conformations within nuclei, chromatin, or DNA-histone complexes. Histone beads elicited antihistone antibodies displaying a sustained IgM isotype in contrast to spontaneously arising autoantibodies in GVH disease which were predominantly IgG. These studies demonstrate that immunization with autoantigens does not usually elicit true autoantibodies and suggest that lymphocyte populations responsible for pseudoautoimmune responses are different from autoantibody-producing cells. We speculate that if autoimmunity is driven by particulate forms of in vivo self-materials, additional factors are required for breaking the natural tolerance to native conformations within the immunogen.

Animals↗
PubMed1989

Methyldopa-induced systemic lupus erythematosus.

Thirteen months after starting methyldopa therapy, a 55-year-old white male patient presented with a syndrome of hemolytic anemia, arthritis, photosensitivity, and a positive antinuclear antibody test result. Methyldopa-induced antinuclear antibodies were mainly IgG, directed against class H1 histones. Antibodies to native DNA and nonhistone proteins were not detected. Upon withdrawal of methyldopa therapy, and with a short course of prednisone and danazol therapy, the patient's symptoms and hemolytic anemia resolved. His clinical symptoms and serologic abnormalities returned to normal and remained negative after 2 years of followup.

Antibodies, Antinuclear↗
PubMed1989

Metabolism of procainamide to the cytotoxic hydroxylamine by neutrophils activated in vitro.

An almost universal side effect of long-term therapy with procainamide is the appearance of serum autoantibodies and less frequently a syndrome resembling lupus erythematosus. Previous studies demonstrated that procainamide-hydroxylamine (PAHA), a metabolite generated by hepatic mixed function oxidases, was highly toxic to dividing cells, but evidence that PAHA could be formed in the circulation was lacking. This study examines the capacity of neutrophils to metabolize procainamide to reactive forms. Neutrophils activated with opsonized zymosan were cytotoxic only if procainamide was present, whereas N-acetyl procainamide, which does not induce autoimmunity, was inert in this bioassay. PAHA was detected by HPLC in the extracellular medium if ascorbic acid was present. Generation of PAHA and cytotoxic procainamide metabolites was inhibited by NaN3 and catalase but not by superoxide dismutase, indicating that H2O2 and myeloperoxidase were involved. Nonactivated neutrophils and neutrophils from patients with chronic granulomatous disease did not generate cytotoxic PAHA, demonstrating that H2O2 was derived from the respiratory burst accompanying neutrophil activation. These conclusions were supported by results of a cell-free system in which neutrophils were replaced by myeloperoxidase and H2O2 or an H2O2 generating system. These studies demonstrate the capacity of neutrophils to mediate metabolism of procainamide and establish the role of myeloperoxidase released during degranulation and H2O2 derived from the respiratory burst in the direct cooxidation of procainamide to PAHA. The profound biologic activity of this metabolite and its possible generation within lymphoid compartments implicate this process in the induction of autoimmunity by procainamide.

Adult↗
PubMed1988

Analysis of the binding of C-reactive protein to histones and chromatin.

C-reactive protein (CRP) is an acute phase serum protein in man which binds to phosphocholine (PC) in a calcium-dependent manner. CRP has been shown to bind to chromatin and nucleosome core particles. However, CRP does not bind to DNA and there is conflicting evidence regarding the binding of CRP to histones. In the present study, binding of CRP to chromatin was confirmed by ELISA using chromatin bound to microtiter wells. When chromatin depleted of histone H1 was used in the same assay, no CRP binding was detected. Similar results were observed using a competitive inhibition ELISA. These results indicate an important role for H1 in the binding of CRP to chromatin. Further studies were done to characterize the binding of CRP to purified individual histones. CRP binding to histones was demonstrated first by blotting. Calf thymus histones were separated on a 15% SDS-polyacrylamide gel, transferred to nitrocellulose, and probed with 125I-CRP. CRP bound to H1 and H2A and to a lesser extent to H2B. Non-specific binding to H3 was seen and no binding to H4 was observed. CRP binding to purified individual histones was tested by ELISA. Essentially identical results were seen to those obtained by blotting. CRP binding to the H2A-H2B complex was observed as well as reactivity with trypsin-resistant fragments of H2A, H2B, and H3. By blotting and by ELISA all CRP reactions were blocked by PC and EDTA indicating binding through the calcium-dependent PC-binding site on CRP. These studies further characterize the nature of the binding of CRP to chromatin and histones and show that the presence of H1 on chromatin is required for CRP binding.

Binding Sites↗
PubMed1988

Association of antibody to histone complex H2A-H2B with symptomatic procainamide-induced lupus.

Antinuclear antibodies develop in most patients who are given prolonged procainamide therapy, but clinical symptoms resembling those of lupus appear in only 15 to 20 percent of such persons. No objective marker for symptomatic procainamide-induced lupus has been described. However, IgG antibodies to the histone complex H2A-H2B have previously been reported in this disorder, and it has been suggested that antiguanosine antibodies may be a marker for major manifestations of procainamide-induced lupus. We therefore tested for these antibodies in 20 symptomatic and 31 asymptomatic patients treated with procainamide. Most of the symptomatic patients had multiple manifestations of drug-induced lupus; resolution of symptoms after the discontinuation of procainamide was required for inclusion in the symptomatic group. All 20 symptomatic patients had elevated IgG antibodies to H2A-H2B, in contrast to only 2 asymptomatic patients (P less than 0.001). This activity was absent in patients not treated with procainamide and in patients with lupus induced by hydralazine or quinidine. IgG antiguanosine was elevated as compared with normal controls in 13 of 20 symptomatic and 19 of 31 asymptomatic patients--a finding that did not distinguish between symptomatic and asymptomatic patients. We conclude that IgG antibodies to H2A-H2B are a sensitive and specific marker for procainamide-induced lupus. The striking correlation between antibodies to H2A-H2B and symptomatic disease suggests a possible association between this antibody and the underlying pathogenic events.

Aged↗
PubMed1988

Dose-dependent induction of anti-native DNA antibodies in cats by propylthiouracil.

Cats receiving propylthiouracil (PTU) develop antinuclear antibodies (ANA) and an immune-mediated disease syndrome characterized by anorexia, lymphadenopathy, weight loss, and Coombs-positive hemolytic anemia. Investigation of the ANA specificity indicated that the predominant ANA activity consistent of anti-native DNA (nDNA) antibodies. The formation of anti-nDNA antibodies and immune-mediated disease syndrome appeared to be dose-dependent, even in cats in which a response had been induced on 4 prior occasions. These results supply further evidence that PTU-induced autoimmunity is not the result of a simple drug allergy. Rather, it appears that PTU induces a lupus-like syndrome, including the hallmark sign of systemic lupus erythematosus, anti-nDNA antibodies.

Animals↗
PubMed1988

Antinuclear antibodies (ANAs): diagnostically specific immune markers and clues toward the understanding of systemic autoimmunity.

The convergence of studies in the clinical and basic sciences has resulted in the definitive identification of many intracellular antigens which are the targets of autoantibodies in patients with systemic lupus erythematosus, scleroderma, dermatomyositis/polymyositis, Sjogren's syndrome, mixed connective tissue disease, and drug-induced autoimmunity. Some of this new knowledge includes the identification of the Sm and RNP antigens as ribonucleoprotein particles involved in splicing of precursor messenger RNA, Scl-70 as DNA topoisomerase I, proliferating cell nuclear antigen as auxiliary protein of DNA polymerase delta, and certain antigens in myositis as aminoacyl transfer RNA synthetases. This information confirms, at a molecular level, the presence of specific profiles of autoimmune responses so that autoantibodies can be used in clinical medicine as diagnostically useful immune markers. In addition the data give compelling reasons to consider that certain autoimmune diseases are antigen-driven. Many auto-antibodies have the interesting feature of recognizing epitopes on the antigens which are active or functional sites of the molecule. It is suggested that the data provide clues to the nature of the intracellular particle initiating the immune response and may help to elucidate some of the early mechanisms of the autoimmune process.

Antibodies, Antinuclear↗