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Biomedical subjects

R L Rubin

Publications and source records attributed to R L Rubin.

At least 37 records · Page 2Linked to original sources
PubMed1996

Intrathymic injection of polynucleosomes delays autoantibody production in BXSB mice.

T-cell dependent autoimmunization with nucleosomes appears to be an early event in the induction of lupus anti-chromatin antibodies. We investigated this phenomenon by injecting H1-stripped chromatin polynucleosomes into the thymuses of BXSB male lupus-prone mice. In comparison to uninjected controls, the production of IgG antichromatin, anti-native DNA, and anti-denatured DNA were significantly reduced among the injected animals for a period of 8 to 10 weeks. Peripheral T-cells from intrathymic (i.t.)-treated animals showed decreased proliferative responses to polynucleosomes compared to those from uninjected controls. Treatment did not affect T-cell antigen receptor V beta profiles, excluding the possibility that results were due to superantigen-imposed deletions. In situ staining using the TUNEL method demonstrated that generation and phagocytosis of apoptotic material in thymuses of unmanipulated BXSB mice were similar to normal controls. These findings show that polynucleosomes likely comprise the antigens for helper T-cell engagement and induction of lupus-associated anti-chromatin antibodies. Bypassing the underlying defect of T-cell tolerance for polynucleosomal antigens among BXSB mice, by i.t. administration of exogenous polynucleosomes, results in abrogation of autoantibody production.

Animals↗
PubMed1996

Autoantibody to the nucleosome subunit (H2A-H2B)-DNA is an early and ubiquitous feature of lupus-like conditions.

Chromatin, a huge polymer of nucleosomes, has been implicated as an important target of autoantibodies in idiopathic and drug-induced lupus for decades, but the antigenicity of chromatin has only recently been dissected. IgG reactivity with the (H2A-H2B)-DNA complex, a subunit of the nucleosome, is present in the majority of patients with systemic lupus erythematosus, in > 90% of patients with lupus induced by procainamide and in individual patients with lupus induced by a variety of other drugs, but is not seen in people taking these medications who are clinically asymptomatic. Anti-[(H2A-H2B)-DNA] accounted for the bulk of the anti-chromatin activity in drug-induced lupus. The earliest detectable autoantibody in lupus-prone mice recognized similar epitopes in the (H2A-H2B)-DNA subnucleosome complex; as the immune response progressed, native DNA and other constituents of chromatin became antigenic. The importance of chromatin-reactive T cells in the anti-[(H2A-H2B)-DNA] response is suggested by the presence of somatic mutations in antibody VH and VL regions, their predominant IgG isotype and the similarity in kinetics of their production to that of conventional T cell dependent antigens. Together with the serologic data from human lupus-like disease, these results are consistent with chromatin being a common stimulant for both B and T cells. While chromatin-reactive antibodies are closely associated with systemic disease and have recently been implicated in glomerulonephritis in SLE, the absence of renal disease in drug-induced lupus indicates that additional abnormalities are required to manifest the serious pathogenic of anti-[(H2A-H2B)-DNA] antibodies.

Animals↗
PubMed1995

IgG but not other classes of anti-[(H2A-H2B)-DNA] is an early sign of procainamide-induced lupus.

A longitudinal study was undertaken to characterize the autoantibodies induced during the course of procainamide treatment and to relate this information to the appearance of symptomatic drug-induced lupus. IgG, IgA, and IgM Abs to histones, native and denatured DNA, chromatin, and (H2A-H2B)-DNA were determined by ELISA in serial serum samples obtained over the course of an average of 2.1 yr on 22 patients undergoing treatment with procainamide and on an additional 9 patients after discontinuation of procainamide because of drug-induced lupus. Ten patients in the prospective group developed lupus-like symptoms after an average of 1.8 +/- 2.1 yr of procainamide treatment. Of the total of 19 patients with drug-induced lupus, 16 had IgG Abs to the (H2A-H2B)-DNA complex at the time of diagnosis; this autoantibody was first detected 0.9 +/- 1.3 yr before diagnosis in 7 patients. In contrast, the 9 patients who remained asymptomatic during treatment with procainamide for an average of 4.3 +/- 2.2 yr had negligible levels of IgG anti-[(H2A-H2B)-DNA], although IgA and IgM Abs of this specificity were not uncommon. Abs to denatured DNA and histones were elicited coordinately, but these specificities did not discriminate symptomatic from asymptomatic procainamide-treated patients. We conclude that chronic exposure to procainamide commonly elicited autoantibodies with specificities for denatured epitopes on DNA and histones and for native regions on the (H2A-H2B)-DNA subunit of chromatin. However, rapid switch to the IgG class of anti-[(H2A-H2B)-DNA] occurred only in patients who went on to develop symptomatic disease.

Antibodies, Antinuclear↗
PubMed1995

Autoantibodies to cryptic epitopes of C-reactive protein and other acute phase proteins in the toxic oil syndrome.

Toxic oil syndrome (TOS) was caused by the consumption of rapeseed oil contaminated with derivatives of aniline. Many persons who survived the acute phase developed a puzzling, multi-year chronic disease considered to be inflammatory or autoimmune in nature. In attempting to characterize their autoantibodies, we found that 74% of TOS patients with chronic disease had IgG antibodies to C-reactive protein (CRP). This activity was detectable only when CRP was chemically or physically denatured and behaved like a previously described antibody produced by immunization with the CRP monomer. Significant antibody reactivities to other acute phase proteins, especially alpha 1-antitrypsin and fibrinogen (P < 0.025) and ceruloplasmin (P < 0.05) were also observed. IgG antibodies to cryptic epitopes in CRP and other major serum proteins that increase during the acute phase response may reflect an earlier toxin-mediated insult to the liver that included abnormal biosynthesis of and/or damage to acute phase proteins.

Acute-Phase Proteins↗
PubMed1995

IgA antihistone antibodies in isoniazid-treated tuberculosis patients.

A retrospective study of tuberculosis patients treated with isoniazid was undertaken in order to establish the prevalence and specificity of antibodies against histones, chromatin and denatured DNA. Each patient had an average of 2.7 +/- 0.4 antibody activities out of the 8 tested antigens using ELISA. These reactivities tended to be higher for non-native forms of the antigens such as denatured histones and DNA with essentially no reactivity to the (H2A-H2B)-DNA subunit of chromatin. Greater than half of the patients were isotype restricted to only IgA or IgM antihistone antibodies, and IgA antihistone antibodies were the most common and reactive. Thirty-five percent of the patients had elevated levels of one or more immunoglobulin classes, and the IgA level was strongly correlated with IgA antihistone activity. These results suggest that isoniazid treatment results in modest increases in antihistone antibodies of the specificities and class typical of drug-induced autoimmunity in the absence of lupus-like disease. The IgA antihistone predominance suggests that serum antoantibodies may be the consequence of stimulation by isoniazid of lymphocytes in the gut-associated Peyer's patches or intestinal lymphoid follicles.

Adolescent↗
PubMed1994

Transformation of lupus-inducing drugs to cytotoxic products by activated neutrophils.

Drug-induced lupus is a serious side effect of certain medications, but the chemical features that confer this property and the underlying pathogenesis are puzzling. Prototypes of all six therapeutic classes of lupus-inducing drugs were highly cytotoxic only in the presence of activated neutrophils. Removal of extracellular hydrogen peroxide before, but not after, exposure of the drug to activated neutrophils prevented cytotoxicity. Neutrophil-dependent cytotoxicity required the enzymatic action of myeloperoxidase, resulting in the chemical transformation of the drug to a reactive product. The capacity of drugs to serve as myeloperoxidase substrates in vitro was associated with the ability to induce lupus in vivo.

Animals↗
PubMed1994

Antibodies to HMG proteins in patients with drug-induced autoimmunity.

OBJECTIVE: To determine the prevalence of autoantibodies to high-mobility group (HMG) proteins in sera from patients with drug-induced lupus (DIL). METHODS: Forty-two patients who developed autoantibodies and/or lupus after treatment with procainamide or other drugs were tested for HMG autoantibodies by immunoblotting and enzyme-linked immunosorbent assay (ELISA). RESULTS: Twenty-eight of the 42 sera (67%) bound HMG-14 and/or HMG-17. In comparison, 9 of 42 (21%) bound HMG-1 and/or HMG-2. There was a good correlation between ELISA results and binding on immunoblots. CONCLUSION: The high prevalence of antibodies to the nucleosomal core HMGs (HMG-14 and HMG-17) in DIL patients adds evidence implicating nucleosomes as immunogens in drug-induced autoimmunity.

Acebutolol↗
PubMed1994

The central role of chromatin in autoimmune responses to histones and DNA in systemic lupus erythematosus.

To gain insight into the mechanisms of autoantibody induction, sera from 40 patients with systemic lupus erythematosus (SLE) were tested by ELISAs for antibody binding to denatured individual histones, native histone-histone complexes, histone-DNA subnucleosome complexes, three forms of chromatin, and DNA. Whole chromatin was the most reactive substrate, with 88% of the patients positive. By chi-square analysis, only the presence of anti-(H2A-H2B), anti-[(H2A-H2B)-DNA], and antichromatin were correlated with kidney disease measured by proteinuria > 0.5 g/d. SLE patients could be divided into two groups based on their antibody-binding pattern to the above substrates. Antibodies from about half of the patients reacted with chromatin and the (H2A-H2B)-DNA subnucleosome complex but displayed very low or no reactivity with native DNA or the (H3-H4)2-DNA subnucleosome complex. An additional third of the patients had antibody reactivity to chromatin, as well as to both subnucleosome structures and DNA. Strikingly, all sera that bound to any of the components of chromatin also bound to whole chromatin, and adsorption with chromatin removed 85-100% of reactivity to (H2A-H2B)-DNA, (H3-H4)2-DNA, and native DNA. Individual sera often bound to several different epitopes on chromatin, with some epitopes requiring quaternary protein-DNA interactions. These results are consistent with chromatin being a potent immunogenic stimulus in SLE. Taken together with previous studies, we suggest that antibody activity to the (H2A-H2B)-DNA component signals the initial breakdown of immune tolerance whereas responses to (H3-H4)2-DNA and native DNA reflect subsequent global loss of tolerance to chromatin.

Animals↗
PubMed1994

Antihistone antibody profile in sulfasalazine induced lupus.

Two patients developed drug induced lupus secondary to sulfasalazine (SSZ). One patient was receiving SSZ for Crohn's disease and was subsequently treated with olsalazine, which lacks the sulfapyridine component of SSZ. Her inflammatory bowel disease (IBD) remained controlled and she did not develop a recurrence of lupus, suggesting that olsalazine is safe in patients with IBD and a history of SSZ induced lupus. The SSZ induced antibodies were predominantly IgG against the (H2A-H2B)-DNA complex. Since lupus induced by 7 other drugs was associated with a similar antibody response, our findings support the existence of a common pathway for autoantibody induction.

Adolescent↗
PubMed1994

Antihistone antibodies in systemic lupus erythematosus: assay dependency and effects of ubiquitination and serum DNA.

OBJECTIVE: Antihistone antibodies occur in systemic lupus erythematosus (SLE) but there are many discrepancies in their reported prevalence, isotype, specificity and correlation with disease symptoms. We examined the role of the assay and the influence of serum DNA as possible causes of these discrepancies. In addition, we sought to confirm the presence of antibodies to ubiquitin and ubiquitinated H2A (uH2A). METHODS: Western blot and enzyme linked immunosorbent assay (ELISA). RESULTS: Sera displayed substantial differences between ELISA and Western blot in reactivity to individual histones when all reagents were nearly identical, indicating that subtle differences in the solid phase adsorbents have pronounced effect on histone antigenicity. No uniform pattern of antibody reactivity with the 5 histones was apparent with either assay. For most sera, digestion with DNase caused only minor decrease in binding to histones and no histone class showed particular sensitivity to this treatment. In agreement with most other studies, no significant correlation between histone binding and symptoms was found. Just 2 of 40 sera showed detectable binding to ubiquitin or uH2A. CONCLUSION: Although IgG antihistone antibodies were detected in 53-55% of patients with SLE with active disease, the sensitivity of antibody activity to assay conditions, patient variability, and lack of correlation with symptoms compromise the clinical utility of measuring antihistone antibodies by Western blot or ELISA: We were also unable to confirm that ubiquitin and uH2A are major antigens recognized by antibodies in SLE.

Adult↗
PubMed1993

Enhanced phosphorylation and dephosphorylation of a histone-like protein in response to hyperosmotic and hypoosmotic conditions.

Placement of endothelial cells under hypoosmotic or hyperosmotic conditions results in the reduction and increase, respectively, in the phosphorylation of a M(r) = 16,500 protein (P17). The changes were dose-dependent with a 3.3 +/- 0.3-fold increase occurring at 485 mosm/kg H2O and negligible phosphorylation observed at 202 mosm/kg H2O. The phosphorylation and dephosphorylation were rapid and prolonged; modified phosphorylation levels were maintained as long as the anisotonic conditions were present. However, return to isotonic medium reversed the phosphorylation back to normal within 1 h. Cellular fractionation studies showed that P17 was associated only with the nuclear compartment under isotonic, hypertonic, or hypotonic conditions. Two forms of P17 with pI values of 9.2 and 9.6 were resolved by isoelectric focusing; both forms showed enhanced phosphorylation by hyperosmotic treatment. Phosphorylation occurred on serines exclusively. These studies demonstrate that a nuclear protein with characteristics similar to histones is affected by cell shrinkage or swelling through changes in its phosphorylation state.

Cells, Cultured↗
PubMed1993

Autoantibodies to chromatin components in juvenile rheumatoid arthritis.

OBJECTIVE: To characterize autoantibodies to chromatin components in patients with juvenile rheumatoid arthritis (JRA). METHODS: The sera of 50 children with JRA were analyzed for antinuclear antibodies (ANA) by immunofluorescence and enzyme-linked immunosorbent assay (ELISA) techniques. RESULTS: By immunofluorescence, ANA and antibodies to high-mobility group proteins or to DNA-free histones were common in patients with pauciarticular JRA and rheumatoid factor-positive polyarticular JRA. However, reactivity with histone-DNA complexes was rare. CONCLUSION: Because antihistone antibodies detected by ELISA failed to bind chromatin or other histone-DNA complexes, they are not likely to represent the immunofluorescent ANA activity in serum.

Adolescent↗
PubMed1993

Genesis and evolution of antichromatin autoantibodies in murine lupus implicates T-dependent immunization with self antigen.

Autoantibodies reacting with chromatin and its components, histones and DNA, are characteristic of the human autoimmune disease SLE and drug-induced lupus, but the mechanisms of their induction remain unknown. Serial serum samples collected over short intervals from lupus-prone MRL/MP-lpr/lpr and BXSB mice were tested by ELISA on chromatin and its substructures to characterize the initial autoimmune response to these antigens. Direct binding studies demonstrated that the early autoantibodies recognized discontinuous epitopes on native chromatin and the (H2A-H2B)-DNA subnucleosome. As the immune response progressed, native DNA and other chromatin constituents generally became antigenic. Based on adsorption studies and IgG subclass restriction, antibodies to native DNA were more related to chromatin than to denatured DNA. The kinetics of autoantibody appearance and the Ig class distribution were similar to the kinetics and distribution seen in antibodies induced by immunization with an exogenous T-dependent antigen. These results are most consistent with the view that autoantibodies reacting with chromatin are generated by autoimmunization with chromatin, and antibodies to native DNA are a subset of the wide spectrum of antichromatin autoantibodies.

Adsorption↗
PubMed1992

Isotype-restricted hyperimmunity in a murine model of the toxic oil syndrome.

The toxic oil syndrome is characterized by IgE elevation and eosinophilia, as well as scleroderma-like skin manifestations and other symptoms of autoimmune disease. Fatty acid anilides, found in large amounts in adulterated cooking oil, were suspected to be the etiologic agent in this disease. The capacity of oleic acid anilide to induce features of autoimmunity in vivo was investigated. B10.S mice were continuously treated i.p. with oleic acid anilide for 6 wk by using osmotic pumps. A significant increase in IgE and IgM serum levels was observed after 1 to 3 wk; subsequently five of six mice developed IgG1 levels 3.5- to 10-fold higher than the controls. Anilide-treated mice developed splenomegaly with a 2.1- and a 3.5-fold increase in IgM- and IgG-bearing splenocytes, respectively, and a 5.6- and 29-fold elevation in functional IgM- and IgG-secreting cells, respectively. Increased serum levels of predominantly IgM antibodies to histone, denatured DNA, and DNP as well as rheumatoid factor were detected. In vivo expression in the spleen of 10 cytokine genes was also examined, and mRNA encoding IL-1 beta and IL-6 were significantly elevated in splenocytes of anilide-treated mice. The enhanced Ig production suggests that anilide induced a cytokine-mediated polyclonal activation of B cells. Elicitation of IgM antibodies to denatured forms of autoantigens indicates that anilide treatment partially broke autoimmune tolerance in these mice. Anilide-treated mice may be a useful animal model for further exploring the mechanism and pathogenesis of systemic autoimmunity in the toxic oil syndrome.

Anilides↗
PubMed1992

Autoantibody specificity in drug-induced lupus and neutrophil-mediated metabolism of lupus-inducing drugs.

A long-term side effect of therapy with a variety of drugs is a syndrome resembling the idiopathic autoimmune disease, systemic lupus erythematosus. Essentially all patients with drug-induced lupus display autoantibodies to nuclear histone components whose specificity appears to be related to the higher order structure of histones existing in chromatin. IgG antibodies to H1 and the (H2A-H2B)-DNA complex were observed in most patients with lupus induced by procainamide, hydralazine, and quinidine, whereas the H3-H4 tetramer, comprising half the mass of the nucleosome core particle, was largely nonantigenic. IgM antibodies to (H2A-H2B)-containing chromatin subunits were common also. IgM reactivity was observed with the DNA-free H3-H4 tetramer and with H1, especially in hydralazine-induced lupus. These results suggest that IgM antihistone antibodies may result from autoimmunization with a nonnative form of chromatin, whereas IgG antibodies may be selected for reactivity with H1 and a native form of the (H2A-H2B)-DNA subunit of the nucleosome. The chemical basis for induction of autoimmunity by drugs is unclear because lupus-inducing drugs do not have a common structural feature or biological activity nor are they capable of specific reactions with histones, the principal target antigen. However, in the presence of activated neutrophils, procainamide is transformed metabolically to the cytotoxic procainamide-hydroxylamine. Mixing experiments and cell-free studies demonstrated that procainamide was cooxidized with H2O2 by myeloperoxidase released when neutrophils undergo the respiratory burst and degranulation reactions. Preliminary results indicate other lupus-inducing drugs are also biotransformed by this mechanism suggesting that a common denominator linking these drugs may be the capacity to be oxidized to reactive metabolites by the action of activated phagocytic cells.

Antibody Specificity↗
PubMed1992

Systemic lupus erythematosus induced by isoniazid.

The case is described of a 73 year old man who presented with a lupus-like syndrome related to treatment with isoniazid and had IgG antinuclear antibodies against the nucleo-histone complex (H2A-H2B)-DNA. After a short course of treatment with prednisone and discontinuation of isoniazid the patient's lupus symptoms resolved and a gradual decrease in antibodies to (H2A-H2B)-DNA occurred. This case suggests that isoniazid is capable of inducing an autoantibody specificity associated with drug related lupus.

Aged↗