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J F Bach

Publications and source records attributed to J F Bach.

At least 487 records · Page 27Linked to original sources
PubMed1984

A monoclonal anti-DNA antibody also binds to cell-surface protein(s).

A murine monoclonal anti-DNA antibody ( PME77 ) has been found to bind tightly to the plasma membrane of Raji cells. We show here that this monoclonal anti-DNA antibody reacts in a radioimmunoassay with the cell surface of a variety of mammalian cell types and that the antigenic determinant recognized by the monoclonal anti-DNA antibody at the surface of Raji cells is resistant to DNase. It belongs to polypeptides removed from the cell surface by a mild proteinase K treatment.

Animals↗
PubMed1984

Production of anti-thymulin (FTS) monoclonal antibodies by immunization against human thymic epithelial cells.

A monoclonal antibody specific for thymulin (FTS), a thymic hormone initially isolated from serum, was obtained by cell fusion using spleen cells from BALB/c mice immunized with cultured human thymic epithelial cells. Hybridomas were selected according to their capacity to produce antibodies binding specifically to thymic epithelial cells in culture (as assessed by indirect immunofluorescence) and their ability to absorb in vitro the biological activity of synthetic and natural hormone preparations and to induce in vivo the disappearance of endogenous circulating thymulin. In this way monoclonal antibodies were obtained that recognized a subpopulation of nonlymphoid cells on frozen sections of mouse and human thymuses. The epithelial nature of these cells was assessed using an antikeratin antiserum. The binding of the antibodies to thymic cells was completely abolished by its absorption with the synthetic hormone or normal (but not of thymectomized) mouse serum. The thymic specificity of the antibody was further confirmed by the complete absence of binding to sections of all the various lymphoid and epithelial organs examined (from both humans and mice). Double labeling experiments using the monoclonal antibody described above and a monoclonal antibody prepared by immunization with the synthetic peptide showed that the two antibodies bound to the same cell. These results provide further evidence for the exclusive presence of the thymic hormone thymulin in thymic epithelial cells.

Animals↗
PubMed1984

Anti-AChR antibodies, thymic histology, and T cell subsets in myasthenia gravis.

The relationship between the titers of antibody against acetylcholine receptor (AChR) and T helper/suppressor balance (assessed by the OKT4/OKT8 ratio) were investigated in 74 patients with myasthenia gravis (MG). All patients with elevated AChR antibody titers (greater than 100 nM) had hyperplastic thymuses, while most patients with low or negative antibody titers (less than 1 nM) had involuted thymuses. All patients with thymoma had positive, though not very high, antibody titers. No correlation was found between anti-AChR antibody levels and OKT4/OKT8 ratios except for patients with thymoma. Thus, it appears that AChR antibody titers are more closely related to thymic pathology than to peripheral T cell imbalance. These results are consistent with the hypothesis giving a central role to thymic lymphocytes in the AChR antibody production, either as antibody producer B cells or helper T cells.

Acetylcholine↗
PubMed1984

Monoclonal antibodies against blood group antigens.

Monoclonal anti-A, anti-B, anti-H antibodies have been produced by a murine hybridoma. C57BL/6 mice have been immunized by different red blood cells. The main characteristics of these antibodies are the following: specificity: anti-A agglutination only A cells, including A2, A3, Ax (from a panel of 50 cells); anti-B agglutinates only B cells (B3, Bx, cis Ab and acquired B). Anti-H agglutinates all cells except H-deficient red cells. inhibition: it is only inhibited by the saliva of each corresponding secretor subject. immunofluorescence tests: it is able to detect A,B,H antigens on tissue sections, kidney, pancreas, liver. thermodynamics: the association constant is 2.10(7) 1/ml (for anti-A) and 3.10(8) for anti-B and anti-H. All are IgM. Monoclonal anti-N, and some anti-public antibodies such as anti-gerbich and anti-Rh 17 have been obtained too. All these antibodies could be useful as reagents and for the study of weak groups.

ABO Blood-Group System↗
PubMed1984

[Heterogeneity of antibodies blocking the binding of bungarotoxin to the acetylcholine receptor in myasthenia].

Inhibitory effect of myasthenic patients antibodies on alpha-bungarotoxin binding to the human acetylcholine receptor has been demonstrated by radioimmunoassay. By using decamethonium, an acetylcholine agonist, we have shown the existence of two antibody sub-groups reacting with the toxin-binding site: one sub-group is represented by antibodies which block the binding directly, the other by antibodies that inhibit the binding, only in the presence of decamethonium.

Antibodies↗
PubMed1984

[A new specificity for anti-DNA antibodies].

A monoclonal antibody directed against double stranded DNA obtained by fusion between myeloma cells and spleen cells from auto-immune B/W Mice, binds to protein(s) at the plasma membrane of human B lymphoblastoid cell lines Raji.

Animals↗
PubMed1984

Autoimmune mice develop antibodies to thymic hormone: production of anti-thymulin monoclonal autoantibodies from diabetic (db/db) and B/W mice.

Monoclonal autoantibodies specific for the thymic hormone thymulin (FTS-Zn) were obtained by cell fusion with the use of spleen cells from nonimmunized autoimmune B/W or diabetic (db/db) mice and myeloma cells. Culture supernatants were screened for their ability to inhibit in vitro and in vivo the biologic activity of synthetic and natural hormone and to bind specifically to thymic epithelial cells in indirect immunofluorescence. This binding was completely abolished by preincubation of the antibodies with the synthetic hormone. These monoclonal autoantibodies were shown by double labeling experiments to bind the same thymic epithelial cells as the antithymulin monoclonal antibodies prepared by immunization with thymic epithelial cells. These autoantibodies directed against the low m.w. thymic hormone thymulin do not explain the low thymulin serum level found in those mice because there is a concomitant decrease in the number of thymulin-containing cells in the thymus, but they could play a role in the maintenance of T lymphocyte defects observed in these mice.

Absorption↗
PubMed1984

Decreased biological activity of serum thymic hormone (thymulin) in children with nephrotic syndrome.

In 36 children with nephrotic syndrome (NS) a significant decrease of their serum levels of the thymic-hormone--thymulin--was found, in parallel with a diminution of their mean blood zinc levels as compared to 33 control children. The serum level of thymulin normalized after the in vitro addition of ZnCl2. Similar results have previously been reported in mice subjected to a long term zinc deficient diet. It can therefore be assumed that the decreased biological activity of the thymic hormone noted in NS is secondary to a low serum zinc level. These data could explain certain anomalies of T lymphocytes described in childhood NS.

Adolescent↗
PubMed1983

[Plasma androgens in women with disseminated lupus erythematosus].

Plasma androgen levels were determined by radio-immunoassay in 19 female patients (aged 14 to 42 years) with systemic lupus erythematosus (SLE). In 11 patients studied in the active phase of the disease, prior to any corticosteroid therapy, mean (+/- SEM) plasma concentrations (ng/ml) of the following androgens were significantly reduced as compared with controls (12 normal women aged 19-37 years): testosterone (0.119 +/- 0.021 vs 0.330 +/- 0.034, p less than 0.001), dihydrotestosterone (0.078 +/- 0.013 vs 0.150 +/- 0.014, p less than 0.01), dehydroepiandrosterone (1.60 +/- 0.16 vs 4.30 +/- 0.50, p less than 0.001), dehydroepiandrosterone sulfate (480 +/- 102 vs 1020 +/- 92, p less than 0.001), and androstenedione (0.69 +/- 0.22 vs 1.45 +/- 0.18, p less than 0.02). In 8 patients studied while in post-therapeutic remission, six months to seven years after corticosteroid withdrawal, plasma concentrations of the same androgens (except androstenedione) were also significantly reduced as compared with controls, although to a lesser degree. In neither of the two patient groups were cortisol and estradiol levels significantly different from controls. Our results suggest that low plasma androgen levels could be a permanent disorder in female SLE patients, at least in severe forms of the disease.

Adolescent↗
PubMed1983

[Problems posed by pregnancy in women with lupus nephropathy].

The influence of lupus nephropathy on pregnancy and reciprocally was retrospectively studied in a series of 131 pregnancies observed from 1962 to 1981 in 45 systemic lupus erythematosis (SLE) women with renal involvement. Renal biopsy showed proliferative lupus glomerulonephritis in 27. The incidence of live births, corrected for induced abortions, was 87% in 89 pregnancies started before, and 89% in 32 started after the clinical onset of SLE; it was only 63% in 10 cases where lupus nephritis developed during gestation. Relapse or exacerbation of disease activity occurred in 15 (47%) of 32 pregnancies antedated by the onset of SLE, with irreversible renal failure in two cases. Clinical exacerbation of SLE was observed in 13 (76%) of 17 cases where SLE was clinically active at the time of conception, and in only 2 of 15 cases where lupus nephritis was in stable clinical remission for at least 5 months prior to conception. Our data suggest that a successful outcome of pregnancy, without SLE exacerbation, may be expected, even in the more severe forms of lupus nephritis, when gestation begins after a sustained, complete clinical remission.

Adult↗
PubMed1983

Studies of the thymus in mice bearing the Lewis lung carcinoma. I. Thymic natural killer cell activity in 3LL tumor-bearing mice.

Natural killer (NK) cell activity of spleen and thymus was studied in Lewis lung carcinoma (3LL)-bearing mice. A high level of hydrocortisone-sensitive NK cell cytotoxicity was found in the thymus after excision of the primary tumor, but not in nonamputated mice. Conversely, splenic NK cell activity was diminished in nonamputated tumor-bearing mice and remained unmodified in amputated tumor-bearing mice. Excision of the primary tumor prevented tumor-induced thymic atrophy and splenomegaly. Histological study of the thymus revealed the presence of metastatic cells within the cortex. These data suggest that NK cells or their precursors are present in the thymus and can be triggered or unmasked in situ by tumor cells migrating from the primary tumor.

Agglutinins↗
PubMed1983

In vitro modulation of mouse natural killer (NK) cell activity by the serum thymic factor (FTS).

Previous studies indicated that the serum thymic factor (FTS) could modulate in vivo the level of splenic natural killer (NK) cell activity in mice. The present report shows that such an effect is also observed after a short term in vitro incubation of the effector cells with FTS. The regulatory effects of FTS result in an increase or a decrease of the splenic NK cell cytotoxicity depending upon the age and the mouse strain. Furthermore, FTS is able to enhance the NK cell activity of thymus and bone marrow cells which are known to be weakly reactive in NK cytotoxicity. Depletion experiments demonstrated that the FTS-induced increase of NK cell activity was not mediated by Thy 1+ cells nor macrophages, thus suggesting a direct action of FTS on the effector cells. Comparative studies using other thymic hormones revealed similar patterns of reactivity. These results favor the hypothesis of a close relationship between the thymus and NK cells.

Animals↗
PubMed1983

Depletion of helper/inducer T cells after thymectomy in myasthenic patients.

Using monoclonal anti-T-cell antibodies, we have studied peripheral blood T-cell subsets in 53 patients with myasthenia gravis before and after thymectomy (Tx). Before Tx, the mean OKT4/OKT8 ratio was higher in patients than in controls. Furthermore patients showed a high number of cells reacting simultaneously with the OKT4 and OKT8 antibodies. Shortly after surgery, the helper/suppressor ratio was increased in most of the patients, and the doubly reactive subset decreased to normal levels. However, 6 to 12 months after Tx the OKT4/OKT8 ratio was significantly decreased, particularly in patients showing clinical improvement. The percentage of total T cells was slightly but significantly reduced. A group of 14 patients studied more than 2 years after Tx presented very low OKT4/OKT8 ratios. Thymectomy in MG appears to lead to a gradual decrease of the T-helper subset which could contribute to its favorable effect on the course of the disease.

Adult↗