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Biomedical subjects

B Guilbert

Publications and source records attributed to B Guilbert.

At least 37 records · Page 2Linked to original sources
PubMed1988

Polyspecific natural antibodies and autoantibodies secreted by human lymphocytes immortalized with Epstein-Barr virus.

Recent studies have shown that autoreactive B cells and autoantibodies are present in pathological as well as in normal situations. In the present study, we immortalized human B cell lines from normal individuals and from patients with malignant or benign dysglobulinemia with Epstein-Barr virus and examined, after cloning, the autoantibody reactivities of the immunoglobulins secreted by these cells. Forty-two supernatants were analyzed by enzyme-immunoassay on a panel of 13 self and non-self antigens: trinitrobenzenesulfonic acid (TNP), DNA, L-glutamine, L-alanine, L-tyrosine (GAT), actin, myosin, tubulin, albumin, renin, spectrin, transferrin, thyroglobulin, myoglobin, peroxidase, and by immunofluorescence in tissue sections. Fourteen (33%) of the immunoglobulin-secreting cell lines were found to have an autoantibody function; seven secreted IgM, six IgA, and one IgG. The light chains were of the kappa type in 11 cases. The vast majority of these clones reacted with more than five antigens of the panel and all of them reacted with TNP. No correlation was found between a given isotype and an antibody specificity. More than half of these antibodies also reacted with cellular antigens present in tissue sections. None of the four cell lines secreting monoclonal antiviral antibodies reacted with any of the antigens of the panel. The results indicate that immunoglobulins secreted by human monoclonal lymphoid cell lines can have polyspecific autoantibody functions, similar to those found in normal human polyclonal antibodies, in human monoclonal paraproteins and in natural monoclonal antibodies synthesized by murine or rat clones obtained from physiologically normal animals.

Antibodies↗
PubMed1987

Natural autoantibodies in systemic lupus erythematosus.

We have tested the sera of 25 patients with systemic lupus erythematosus (SLE) for antibody activity against a panel of six antigens: DNA, TNP, actin, tubulin, myosin, albumin. Eluates from renal biopsy tissue were also tested. Sera from patients with lupus nephritis were found to contain high titres of IgA antibodies directed against the antigens of the panel, and marked IgG anti-DNA and anti-TNP antibody activity. The IgG anti-TNP antibodies isolated from SLE serum by affinity chromatography on a TNP-immunoadsorbent, were also found to possess anti-DNA activity. Kidney eluates obtained from biopsy specimens of SLE patients contained IgG antibodies strictly specific for DNA in three out of the nine patients tested, while three eluates from the remaining six patients reacted with DNA and TNP and three with DNA and all the other antigens of the panel. These results strongly suggest that in SLE sera there are at least three populations of circulating anti-DNA antibodies: those strictly specific for DNA, those recognizing DNA and TNP and those recognizing DNA and other macromolecules. Furthermore, because six out of nine of the eluates contained antibodies with an absolute or restricted specificity for DNA, this suggests that these antibodies are more often pathogenic than the polyspecific ones recognizing DNA and other macromolecules.

Actins↗
PubMed1987

Suppression of anti-DNA antibody production in MRL mice by treatment with anti-idiotypic antibodies.

Antibodies against idiotypic determinants carried by a monoclonal polyspecific natural autoantibody were raised in rabbits and in syngeneic BALB/c mice. These anti-idiotypic antibodies were administered to newborn and to pregnant BALB/c mice and to MRL-lpr/lpr mice. Serial measurements of the idiotypes, naturally occurring autoantibodies, and antibodies obtained after antigenic stimulation were performed in the sera of the injected mice and in the offspring of pregnant mice. No idiotypic suppression was noted in newborn injected mice. Transient suppression of idiotypes recognized by the syngeneic anti-idiotypic antibody was noted in the offspring of pregnant mice injected with the rabbit polyclonal anti-idiotypic antiserum. No changes in naturally occurring autoantibodies or in antibodies appearing after antigenic stimulation were noted in BALB/c mice. In contrast, a significant decrease of spontaneously occurring anti-DNA antibodies was found in MRL-lpr/lpr mice treated with rabbit polyclonal anti-idiotypic antiserum. Furthermore in these mice a slight decrease of anti-TNP antibodies was also observed. These results suggest that anti-idiotypic antibodies directed against natural autoantibodies may play a regulatory role in the immune system; this role is more easily appreciated in mice suffering from immune dysregulation.

Animals↗
PubMed1986

The Epstein-Barr virus-induced production of IgE by human B cells.

B cells, isolated from the blood of healthy individuals and patients allergic to pollen, produced IgE when exposed to the human B-cell polyclonal activator, Epstein-Barr virus (EBV) in vitro and placed in culture. Secreted IgM and IgE were measured using immunoenzymatic assays. No difference was seen between healthy donors and allergic patients in the amount of IgE (or IgM) secreted. Cells were placed in limiting dilution cultures in order to determine the frequency of cells producing IgE or IgM (total and pollen specific) on exposure to EBV. Again, no significant differences in EBV-driven, B-cell precursor frequencies (PF) were seen between normal and allergic individuals. EBV-driven B-cell PF for total IgM and IgE, and pollen-specific IgM and IgE secretion, were 1/450, 1/6500, 1/83,000, and less than 1 per 2,500,000, respectively, for cells from healthy donors, and 1/140, 1/4000, 1/56,000 and less than or equal to 1 per 2,000,000, respectively, for cells from allergic patients. We propose that the increased IgE levels seen in atopic individuals result solely from regulatory defects, rather than an increase in the frequency of B cells committed to the secretion of IgE.

Allergens↗
PubMed1985

Presence of natural autoantibodies in hyperimmunized mice.

Mice were immunized with various antigens in complete Freund's adjuvant following various injection schedules. Hybridomas were produced from the spleens of these immunized mice and examined for production of antibodies directed against the antigen injected and against a panel of self (tubulin, actin, myosin, DNA) and non-self antigens (myoglobin, spectrin, peroxidase, trinitrobenzene). Two to five percent of the hybrids were found to secrete polyspecific antibodies able to react with two or more antigens of the panel. Several of these hybrids were subcloned and expanded into ascites. The monoclonal immunoglobulins they secreted were isolated and shown to be IgM (kappa) and to possess the polyspecific antibody function. Several hybrids were also found to secrete antibodies reacting with the immunizing antigen as well as one or more antigens of the panel. The antibody secreted by one subclone which reacts with both the immunizing antigen, prolactin and one of the panel antigens, TNP, has been isolated using a DNP-immunoadsorbent. The isolated antibody was found to be a monoclonal IgM (kappa) immunoglobulin and to react both with prolactin and TNP. The hypothesis is advanced that cells carrying polyspecific natural antibodies as receptors after a given antigenic stimulation proliferate into cells producing highly specific antibodies for epitopes of that given antigen; the cells with polyspecific receptors will be continuously replaced by new cells probably on bone-marrow origin.

Animals↗
PubMed1983

Thirty-six human monoclonal immunoglobulins with antibody activity against cytoskeleton proteins, thyroglobulin, and native DNA: immunologic studies and clinical correlations.

Six hundred and twelve monoclonal Ig (MIg) were studied for their antibody activity against the following autoantigens: actin, tubulin, thyroglobulin, myosin, myoglobin, fetuin, albumin, transferrin, and double-stranded DNA (dsDNA). Of these 612 MIg, 36 (i.e., 5.75%) were shown to possess antibody activity. Thirty-two of these 36 (5.22% of the total) were mainly directed against actin. The four others were directed, respectively, against tubulin, myosin, thyroglobulin, and dsDNA. The interaction of the MIg with the respective antigen was demonstrated by immunoenzymatic methods with monospecific antisera and by blotting experiments. Furthermore, this interaction in the 12 cases studied was mediated by the dimeric fragment F(ab')2 of the MIg. The MIg with antitubulin, antithyroglobulin, and anti-dsDNA activities were exclusively inhibited by their homologous antigens. Those with antiactin activity were predominantly inhibited by actin and also by tubulin and thyroglobulin. The one binding to myosin was, for the most part, inhibited by myosin and also significantly by actin and tubulin. Retrospective clinical analysis was possible for 31/36 patients. Twenty-six of 31 had malignant lymphoplasmocytic disorders. The five others were followed for miscellaneous disorders without overt signs of multiple myeloma (MM) or Waldenström's macroglobulinemia (WM). The correlation between the antibody activity of the MIg and the clinical features is discussed. These results indicate that a high proportion of MIg possess antibody activity against actin (5.22%). This incidence contrasts sharply with the positive reactions found toward all the other antigens tested: only one each for dsDNA, tubulin, thyroglobulin, and myosin, and none against myoglobin, fetuin, albumin, and transferrin. The significance of these results and the relationship between MIg and natural antibodies are discussed.

Actins↗
PubMed1979

Skin fibroblast microtubular network in Alzheimer disease.

A preliminary observation from another laboratory recently suggested that a systemic microtubular defect may exist in Alzheimer disease. To investigate this hypothesis, we obtained skin biopsies from 4 patients with Alzheimer disease and 2 age-matched controls. Fibroblast cultures were established and the tubulin networks examined using immunoadsorbent purified antitubulin antibody and the indirect immunoperoxidase technique as well as electron microscopy. The cells were also examined after treatment with vinblastine and at senescence. The microtubular network appeared as delicate fibers radiating from the perinuclear region toward the cytoplasmic margins. No differences were recognized between the controls and the fibroblast cultures from patients with Alzheimer disease. Microtubules were not visualized following incubation with vinblastine, but positively staining intracytoplasmic paracrystalline inclusions were noted. No abnormalities of microtubules were recognized in the electron microscopic examinations. These findings suggest that the neurofibrillary neuronal degeneration of Alzheimer disease is not a manifestation of a systemic disorder of the microtubular network.

Alzheimer Disease↗
PubMed1978

Detection of tubulin and actin in various cell lines by an immunoperoxidase technique.

This paper reports on the preparation of immunsera against tubulin and actin, and the purification of anti-tubulin and anti-actin antibodies on immunoadsorbent columns. These purified antibodies were used in an indirect immunoperoxidase assay to visualize microtubules and microfilaments in various cell lines. The specificity of antibodies and the methods of cell fixation required are discussed, as well as some aspects of microtubule and microfilament organization, as visualized by this technique.

Actins↗
PubMed1977

Antibodies to tubulin in normal nonimmunized animals.

Sera of normal nonimmunized rabbits, pigs, calves, and humans contain tubulin-reactive antibodies. Usually, low amounts of antibodies against tubulin of the IgG class (2.5-4 mg/100 ml of serum from nonimmunized animals) were isolated. Anti-tubulin antibodies were also produced by injecting pig tubulin in complete Freund's adjuvant into rabbits. Slightly higher amounts of anti-tubulin antibody were isolated from sera of immunized rabbits (7 mg/100 ml of serum). The cytoplasmic network of microtubules of Tcc 36 mouse cells in culture was not clearly stained by natural anti-tubulin antibodies, but dense staining of the centrosphere was observed. In contrast, induced anti-tubulin antibodies densely stained cytoplasmic microtubular networks. Vinblastine-induced tubulin paracrystals were equally stained by natural and induced anti-tubulin antibodies.

Animals↗