Biomedical subjects

D S Pisetsky

Publications and source records attributed to D S Pisetsky.

At least 145 records · Page 8Linked to original sources

PubMed1990

Regulation of the anti-Sm autoantibody response in systemic lupus erythematosus mice by monoclonal anti-Sm antibodies.

The administration of certain monoclonal anti-Sm antibodies (2G7, 7.13) induced most MRL/lpr mice to become anti-Sm positive by 5 mo of age, although other anti-Sm monoclonals (Y2, Y12) suppressed the spontaneous response. Positive anti-Sm antibody enhancement occurred efficiently only in MRL/lpr mice and not in other systemic lupus erythematosus mice that have little spontaneous anti-Sm production. The enhancement by anti-Sm antibodies was specific for the anti-Sm response. The mechanism of the passive antibody enhancement was apparently not isotype- or idiotype-related. The fine specificity of the anti-Sm monoclonal antibody may be essential to its enhancing or suppressing effects, since both enhancing monoclonals recognized only the D Sm polypeptide, whereas both suppressing monoclonals saw the D and the B polypeptides. Furthermore, analysis of serial bleeds from unmanipulated MRL mice that developed anti-Sm positivity showed that the D specificity almost always appeared first. We hypothesize, therefore, that those animals in which an anti-Sm response is initiated by D-specific B-cell clones can become serologically positive with the aid of a positive feedback loop. In contrast, animals in which the initial specificity is for both B and D peptides would be prevented from developing a full anti-Sm response.

Animals↗

PubMed1990

Temporal correlation of antibody responses to different epitopes of the human La autoantigen.

To investigate the temporal relationship of antibody responses to different La epitopes, sequential sera from nine patients with systemic lupus erythematosus and Sjogren's syndrome were tested by enzyme-linked immunosorbent assay for antibody binding to a series of recombinant fusion proteins containing different regions of the La molecule. The results of this analysis indicate that antibody responses to four different La fragments vary in parallel over time. This finding is supported by a statistical analysis indicating that the changes in antibody levels between the six pairs of responses were highly correlated (P less than 0.001). Furthermore, we show by immunoaffinity purification that antibodies to the three nonoverlapping La protein fragments do not cross-react with other fragments and, hence, represent independent populations. These results suggest that anti-La antibodies are coordinately produced to different epitopes on the La molecule, possibly reflecting an antigen-driven mechanism.

Antibodies, Antinuclear↗

PubMed1990

In vitro autoantibody production by normal adult and cord blood B cells.

To investigate the repertoire of autoantibodies in humans, anti-DNA and rheumatoid factor (RF) production in vitro was assessed in cultures of adult peripheral blood B cells and neonatal umbilical venous blood B cells. B cells were stimulated under various culture conditions, using an immobilized monoclonal anti-CD3 antibody and adult T cells or Staphylococcus aureus (SA) in the presence or absence of adult T cells or factors derived from mitogen-stimulated adult T cells as polyclonal B cell activators. Total IgM, as well as IgM anti-DNA and RF, were assessed by ELISA. Total IgM production was induced from adult and neonatal B cells with SA plus T cell factors, as well as anti-CD3-stimulated T cells. RF was induced from adult and cord blood B cells by either mode of stimulation, whereas significant anti-DNA production was observed only when B cells were stimulated with anti-CD3-activated T cells. These results confirm the presence of B cell precursors for autoantibodies in the preimmune as well as normal adult repertoire, and indicate that the production of anti-DNA and RF appears to be regulated independently.

Adult↗

PubMed1990

Selective recognition of DNA antigenic determinants by murine monoclonal anti-DNA antibodies.

To assess the immune recognition of DNA in systemic lupus erythematosus, the antigenic specificity of monoclonal anti-DNA antibodies from autoimmune MRL-lpr/lpr mice was investigated Determinant specificity was assessed by ELISA in terms of binding to a panel of ssDNA antigens including calf thymus, human placenta, Escherichia coli, Clostridium perfringens, Micrococcus lysodeikticus, salmon testes, chicken blood and murine DNA. Among the monoclonal antibodies, a variety of binding patterns was observed, although for all antibodies tested murine DNA was among the most reactive antigens. Binding to other DNAs varied markedly, with some antibodies showing only low reactivity to certain antigens in the test panel. Similar results were obtained with sera of individual MRL-lpr/lpr mice. These results suggest that anti-DNA antibodies bind specific antigenic determinants variably expressed by DNAs of various species. Furthermore, the preferential binding to mouse DNA by some MRL-lpr/lpr antibodies may suggest a role of self-DNA in the in vivo selection of anti-DNA antibodies for expression.

Animals↗

PubMed1990

IgG binding of monoclonal anti-nuclear antibodies from MRL-lpr/lpr mice.

To assess the specificity of anti-nuclear antibodies with cross-reactive rheumatoid factor (RF) activity, monoclonal anti-DNA and anti-Sm antibodies from MRL-lpr/lpr mice were tested for binding to a variety of IgG antigens. These antibodies had all been previously identified as binding heterologous IgG. By ELISA, antibodies in this panel all bound BALB/c myeloma proteins representing the different IgG subclasses, indicating broad reactivity with murine IgG as well as heterologous IgG. The determinant recognized by these antibodies was further investigated using the Fab, F(ab')2 and Fc fragments of both human as well as rabbit origin. All antibodies bound well to fragments as well as intact IgG antigens. These antibodies were further analysed by Western blotting, demonstrating that most bound to both heavy and light chains of human origin. Together, these observations suggest that some anti-nuclear antibodies bind a conserved antigenic determinant present widely on immunoglobulin chains. This determinant may represent a common sequence important in immunoglobulin domain structure.

Animals↗

PubMed1989

Polyspecific binding of Escherichia coli beta-galactosidase by murine antibodies to DNA.

To characterize further polyspecific interactions of antibodies to DNA, the binding of sera from autoimmune MRL-lpr/lpr mice to Escherichia coli beta-galactosidase (beta-gal) was analyzed. This protein was selected for study because of preliminary observations that sera from autoimmune mice bound unexpectedly to cloned fusion protein constructions containing beta-gal. Using ELISA assays, sera from MRL-lpr/lpr mice demonstrated high levels of antibodies to both DNA and beta-gal, in titers significantly greater than those of BALB/c controls. Affinity chromatography using beta-gal-Sepharose demonstrated that antibodies enriched for anti-beta-gal activity bound both DNA as well as beta-gal, indicating the presence of a population of cross-reactive anti-DNA antibodies. Furthermore, anti-DNA mAb of MRL-lpr/lpr strain origin also bound beta-gal by ELISA, although these levels were lower than those to DNA. Together, these results extend the range of polyspecific binding of murine anti-DNA antibodies to bacterial proteins. They further suggest caution in the interpretation of immunoassays using fusion protein constructions containing beta-gal, especially with sera from autoimmune mice.

Animals↗

PubMed1989

Induction of anti-double stranded DNA antibodies in normal mice by immunization with bacterial DNA.

Because of recent observations suggesting that bacterial DNA is immunogenic, the induction in normal mice of antibodies to Escherichia coli (EC) dsDNA was investigated. BALB/c and C57BL/6 mice were immunized with dsEC or ds calf thymus (CT) DNA complexed to methylated BSA in adjuvant; antibody responses were measured by ELISA. In both strains, dsEC DNA immunization induced a much higher anti-dsDNA response to dsEC DNA than did dsCT DNA immunization. Neither immunized group showed an appreciable antibody response when tested on dsCT DNA. Anti-dsDNA antibodies were also demonstrated by ELISA using synthetic DNA duplexes as well as a filter binding assay using 3H-labeled dsEC DNA as Ag. These results suggest that bacterial dsDNA is immunogenic and that at least some anti-dsDNA specificities can arise by immunization.

Animals↗

PubMed1989

Genetic control of inflammatory arthritis in congenic lpr mice.

To determine the genetic requirements for the development of inflammatory arthritis in MRL-lpr/lpr mice, clinical, serologic, and pathologic features of lpr/lpr and +/+ mice of MRL, B6, C3H, and AKR strains were studied. Arthritis was evaluated by histopathologic examination of the knee joint, while sera were tested for the presence of rheumatoid factor (RF) and anti-DNA activity by ELISA. Of the strains tested to age 7 months, only the MRL-lpr/lpr mice developed histologic evidence of arthritis. All lpr mice, however, produced both IgM RF and IgG RF, although amounts varied among strains. These results indicate that the lpr gene as well as another gene(s) in the MRL background are necessary for the development of inflammatory arthritis and that this lesion may be independent of RF production.

Animals↗

PubMed1989

The antibody response of normal mice to immunization with single-stranded DNA of various species origin.

To further assess the mechanism for the induction of anti-DNA antibodies, the response of BALB/c mice to immunization with single-stranded DNA of various species origin was determined. Anti-DNA levels of mice immunized with Escherichia coli DNA as complexes with methylated BSA in adjuvant were significantly greater by ELISA than those from mice immunized similarly with calf thymus DNA. Furthermore, comparison of the responses of mice immunized with complexes of DNA from calf thymus, chicken blood, Clostridium perfringens, E. coli, human placenta, or salmon testes indicated that the bacterial DNAs induced the highest antibody levels. The antibody response to E. coli DNA was shown by inhibition ELISA to have two populations, one binding unique determinants in E. coli DNA and the other cross-reactive with determinants expressed on all DNAs tested. These results indicate that DNA molecules, when complexed to a protein carrier, differ in their immunogenic potential, likely because of the presence of unique sequences or structures rarely presented by mammalian host DNA.

Animals↗

PubMed1989

Epitope specificity of anti-La antibodies from patients with Sjögren's syndrome.

To investigate patterns of autoreactivity in Sjögren's syndrome, the epitope specificity of anti-La antibodies was determined using recombinant antigens bearing sequences of the amino, middle, and carboxyl portions of the La molecule. Sera from patients with primary as well as secondary Sjögren's syndrome reacted with all three fragments, although the magnitude of the responses varied markedly among individuals. Furthermore, the proportion of antibody binding directed to the different La epitopes showed considerable individual variations, but these patterns were not correlated with specific clinical manifestations. These results suggest that quantitative and qualitative aspects of anti-La responses in Sjögren's syndrome are determined by factors distinct from those determining the clinical expression of disease.

Antibodies↗

PubMed1989

Antidouble stranded DNA antibody assays in systemic lupus erythematosus: correlations of longitudinal antibody measurements.

To determine whether different assays of antidouble stranded DNA (anti-dsDNA) antibodies provide comparable information in quantitative antibody assessment over time, longitudinal correlations between 3 anti-dsDNA antibody methods were derived. Determinations of anti-dsDNA antibody levels on serial samples from 9 patients with systemic lupus erythematosus (SLE) were performed by filter binding radioimmunoassay, enzyme linked immunosorbent assay, and Crithidia indirect immunofluorescence. Substantial pairwise correlations among assay methods were found (r = 0.544 to 0.804; p less than 0.001). In addition, anti-dsDNA antibody levels as measured by each assay were inversely correlated with levels of the 3rd component of complement. Our results indicate that changes in antibody levels as determined by these 3 methods closely parallel each other over time, and suggest that the array of anti-dsDNA antibodies detected in patient sera remains relatively constant over time.

Adolescent↗

PubMed1989

Patterns of autoantibody expression in pediatric and adult systemic lupus erythematosus.

To characterize patterns of autoantibody expression in pediatric and adult systemic lupus erythematosus (SLE), IgG and IgM antibodies to cardiolipin (aCL) and single-stranded DNA (anti-DNA) were measured in sera from 32 pediatric and 36 adult patients. Antibody levels were assessed by isotype-specific ELISA and compared with 15 pediatric disease controls and 36 healthy adult controls. These determinations revealed significant differences in the pattern of IgG and IgM autoantibody expression in adult and pediatric patients. IgM aCL were more common in the pediatric than adult SLE population with 11 of 32 pediatric patients being positive compared to only 4 of 36 in the adult group (p less than 0.05). Conversely, enhanced IgG autoantibody production was observed in the adult group as 27 of 36 adult patients were positive for IgG anti-DNA compared to only 16 of 32 children (p less than 0.05). Analysis of sequential sera showed differences in the temporal expression of IgG and IgM autoantibodies as well as variability between anti-DNA and aCL responses over time. Our data suggest differences in the isotype profile of autoantibody responses in pediatric and adult SLE and provide further evidence for heterogeneity in the mechanisms of autoantibody production.

Adolescent↗

PubMed1988

Analysis of autoantibody binding to different regions of the human La antigen expressed in recombinant fusion proteins.

To determine the specificity of autoantibodies for various antigenic sites on a self-protein molecule, sera from 19 patients with anti-La antibodies were tested for their reactivity with molecularly cloned La protein fragments. By quantitative ELISA, anti-La sera from patients with various connective tissue diseases were shown to react with La fusion proteins containing different regions of the La molecule. Two recombinant La fragments containing the carboxyl three-fourths and the middle one-third of the La sequence, respectively, bound higher levels of anti-La antibodies than the two fragments representing the amino and carboxyl terminals. Purified bovine La protein effectively competed for the binding of human autoantibodies to three of the four recombinant La fusion proteins, suggesting similarity in antigenic presentation between the La epitopes in these fusion proteins and the native La molecule. Immunoadsorption experiments showed that most anti-bovine La protein antibodies were removed from a human serum by affinity chromatography by using the fusion protein containing the carboxyl three-fourths of the La sequence, thus supporting the results obtained by quantitative solid phase ELISA. These studies demonstrate that anti-La autoantibodies recognize three La fragments representing separate nonoverlapping regions of the La sequence and are compatible with a mechanism of autoantibody production based on an immune response to the entire self-protein molecule.

Autoantibodies↗

PubMed1988

Spontaneous expression of antibodies to DNA of various species origin in sera of normal subjects and patients with systemic lupus erythematosus.

To investigate mechanisms for the induction of anti-DNA antibodies in systemic lupus erythematosus (SLE), the specificity of anti-DNA antibodies was determined in sera from SLE patients and normal control subjects. As a marker of these responses, the reactivity to single-stranded DNA of various mammalian and bacterial species origin was tested by enzyme-linked immunosorbent assay. Patients with SLE demonstrated serum antibodies to all six types of DNA tested, whereas normal control subjects showed appreciable antibody responses only to DNA obtained from Micrococcus lysodeikticus (MC) and Staphylococcus epidermidus (SE). Anti-DNA antibodies in normal sera appeared to recognize unique sites on the DNA because MC DNA failed to inhibit antibody binding to SE DNA, and vice versa; in contrast, SLE antibody binding to MC DNA could be inhibited by SE as well as other DNA, suggesting recognition of a more widely shared epitope. The expression in normal sera of antibodies specific for certain bacterial DNA is consistent with their induction by structural determinants on these DNA molecules that are immunogenic. DNA may therefore represent another bacterial macromolecule capable of inducing cross-reactive antibodies in human autoimmune disease.

Adult↗

PubMed1988

Quantitative immunoassay of anti-La antibodies using purified recombinant La antigen.

A purified recombinant La fusion protein was tested in an enzyme-linked immunosorbent assay to quantitate anti-La responses. This protein contained the immunodominant region of the La molecule fused to beta-galactosidase. In solid-phase assays, recombinant La protein was solubilized in urea and bound to polystyrene wells without loss of immunoreactivity. The recombinant-based enzyme-linked immunosorbent assay proved to be a sensitive method for the detection of anti-La binding, and it accurately distinguished anti-La precipitin positive sera from normal sera.

Antibodies↗

PubMed1988

Mike's treatment.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Methotrexate-associated hepatotoxicity: retrospective analysis of 210 patients with rheumatoid arthritis.

PURPOSE: Beginning in the 1980s, methotrexate has been used successfully to treat rheumatoid arthritis. The magnitude and severity of short- and long-term methotrexate toxicity, however, have not been adequately investigated. Our study was performed to determine the prevalence of hepatotoxicity in patients with rheumatoid arthritis receiving long-term methotrexate therapy. PATIENTS AND METHODS: We conducted a retrospective, computer-assisted review of all Duke University Medical Center patients undergoing liver biopsy for methotrexate monitoring from January 1979 to January 1988. A total of 538 biopsies were performed in 399 patients, 259 of whom had inflammatory arthritis (210 with rheumatoid arthritis, 47 with psoriatic arthritis, and two with seronegative spondyloarthropathy). RESULTS: No evidence of cirrhosis was defined in the cohort with rheumatoid arthritis; however, six patients with rheumatoid arthritis had histologic changes of fibrotic liver disease (prevalence of 2.9 percent in the group with rheumatoid arthritis) while taking methotrexate. Five of the six patients were obese and three had glucose intolerance or overt diabetes mellitus, and one person admitted to alcohol usage. Only one patient with fibrotic liver disease had elevated liver function test results, and no person showed a declining serum albumin level at the time of biopsy. Sixty-one patients with rheumatoid arthritis underwent multiple samplings (44 with two, 13 with three, and four with four biopsies). Fourteen of these patients showed progressive hepatic disease, whereas four patients improved. CONCLUSION: Although the prevalence of methotrexate hepatotoxicity in this large cohort of patients with rheumatoid arthritis was low, a small but definite risk of hepatic fibrosis, not predictable by laboratory screening, still exists.

Aged↗

PubMed1988

Inhibition of in vitro NZB antibody responses by cyclosporine.

To characterize functional abnormalities of B cells in murine autoimmunity, the effect of cyclosporine (CsA) on antibody responses of NZB and control BALB/c spleen cells was investigated in vitro. Under conditions of high cell density, both NZB and BALB/c spleen cells spontaneously produced IgM and IgM anti-DNA, although NZB responses were greater in magnitude and demonstrated at lower cell densities. In cultures at 5 x 10(6) cells/ml, CsA preferentially inhibited anti-DNA production by cells of both strains. However, to achieve similar levels of inhibition of both responses, significantly higher concentrations of CsA were required for cultures of NZB compared to BALB/c cells. These results support previous experiments indicating enhanced sensitivity to CsA as a pharmacological marker of autoantibody producing B cells. They further suggest that B cell activation in certain forms of autoimmunity may be associated with decreased sensitivity to immunosuppressive agents.

Animals↗