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J F Bach

Publications and source records attributed to J F Bach.

At least 559 records · Page 31Linked to original sources
PubMed1981

[Modification of the antigenicity of the serum thymic factor (thymulin) by zinc].

We have previously reported that the serum thymic factor (FTS) exists under two forms, one deprived of zinc, biologically inactive and another one containing zinc, biologically active for which we have proposed the name of thymulin (FTS-Zn). A new iodinated tracer (125I FTS-Zn) has been prepared by fixing zinc on synthetic FTS. This tracer is recognized by a Rabbit anti-FTS antiserum at a 1/20,000 dilution. Normal Mouse sera displace the binding of FTS-Zn to the antiserum (40-60% inhibition) whereas thymectomized mouse sera have no effect. These results should allow the establishment of a simple radioimmunoassay for thymulin (FTS-Zn) present in biological fluids.

Animals↗
PubMed1981

[Role of zinc and other metals in the biological activity of the serum thymic factor (thymulin)].

The serum thymic factor (FTS) used in synthetic or natural form, loses its biological activity after passage on a chelating agent, Chelex 100. Such activity is recovered after addition of zinc and, to a lesser degree, of certain other metals. FTS activation is secondary to zinc binding to the peptide. These results indicate the existence of two FTS forms: the first one, deprived of zinc and biologically inactive, the second one containing zinc and biologically active, for which we purpose to coin the name of thymulin.

Animals↗
PubMed1981

Cellular and molecular signals in T cell differentiation.

The thymic epithelium exerts its differentiative effects through several mechanisms, involving direct contact with stem cells as well as secretion of various thymic hormones. Indirect and direct evidence suggests that the thymus produces chemotactic factors for the stem cells that colonize the thymus anlage. The epithelium also produces several maturational factors which act upon stem cells that have undergone primary differentiation by contact with thymic epithelium. The chemical characteristics of these hormones and their mode of action at the cellular level (high affinity receptors, metabolic effects, target cells) are partly known. Their relationship with T cell factors such as Interleukin-2--produced in the periphery and endowed with strong differentiative capacity--is intriguing, the more so because thymic hormones not only act within the thymus but also affect peripheral T cells after they have emigrated from the thymus.

Animals↗
PubMed1981

Detection and characterization of lymphocytes bearing receptors for peanut agglutinin by a specific rosetting technique.

Murine lymphocytes bearing receptors for peanut agglutinin (PNA) have been visualized using a specific rosetting technique. The lymphocytes were incubated with PNA and mixed with neuraminidase-treated sheep red blood cells. The percentage of the PNA rosetting lymphocytes found in the various organs studied was dependent upon the PNA concentration. In the spleen, the PNA rosetting lymphocytes were primarily T cells with low PNA concentration while both T and B lymphocytes were rosetted with high PNA concentration. In the fetal liver and thymus PNA rosetting lymphocytes were present in small amounts early in fetal life, increasing and reaching adult levels by late fetal life. The present study shows that the rosetting technique is more sensitive than previously described techniques for the detection of various lymphocyte subpopulation having receptors for PNA.

Animals↗
PubMed1981

Imbalance in T cell subsets in human diseases.

T cell subsets have been evaluated in 232 patients with various immunological diseases and 41 normal individuals used as a control group. An increase in the helper/suppressor ratio (OKT4:OKT8) was often noted in multiple sclerosis (acute attacks and progressive forms), autoimmune hemolytic anemia (without steroids), membranous and IgA-deposit glomerulonephritis, HBs-negative chronic active hepatitis, lepromatous patients with erythema nodosum, and myasthenia gravis. Ratios were usually normal in membranoproliferative nephritis, in lupus erythematosus (at least in steroid treated cases) and in nephrotic syndrome. High values of helper cells have been found in Sezary's syndrome (with low or no suppressor cells) and in mycosis fungoides. Variable data have been obtained in immunodeficiency syndromes. These data have been correlated with age, sex and clinical parameters, as well as with other immunological tests (E rosettes, mitogen responses, mixed lymphocyte reaction, Concanavalin A-induced suppression). From our investigations we have concluded that the study of OKT antibody-defined T cell subsets offers a valuable technique for the further investigation of human immunological diseases.

Anemia, Hemolytic, Autoimmune↗
PubMed1981

Antithymocyte globulin in cadaver kidney transplantation: a randomized trial based on T-cell monitoring.

The influence of horse antihuman thymocyte globulin (ATG) on renal allograft survival was assayed between March 1977 and August 1978. Fifty consecutive patients were randomly assigned to the treatment or the control group. Patients in both groups received azathioprine and prednisolone. ATG was added in the experimental group. The daily dosage was such as to maintain the rosette-forming cell (RFC) level at 10% of baseline values. The number of renal failure episodes (RFE's)was significantly lower in the experimental group during the period (1 month) ATG was given than it was in the control group during that same period of time. Two years after transplantation, kidney survival was 79% in the ATG group and 52% in the control group. The amount of steroids necessary to control RFE's was significantly lower in the ATG group. The dosages of ATG used in the experimental group were relatively small (average daily dose, 3.08 +/- 0.26 mg/kg of body wt), and adverse reactions were mild. Blood tolerance was excellent. T-cell monitoring thus appears to be an effective method in evaluating the daily dosage of ATG.

Adolescent↗
PubMed1981

Immunological studies in human ageing. II. Associated increase in anti-RNA and anti-DNA antibodies.

Antibodies against nucleic acids have been studied by counter-immunoelectrophoresis in 95 aged subjects. Increased levels of anti-DNA and/or anti-RNA antibodies were found in 74% of the cases, and immune complexes were detected in 21% of the cases. The increase of anti-DNA antibodies was correlated with that of rheumatoid factor and increased serum IgG levels, whereas the increase of anti-RNA antibodies was associated with decreased serum IgM level and decreased lymphocyte response to PHA.

Adolescent↗
PubMed1981

Immunological studies in human ageing. I. In vitro functions of T cells and polymorphs.

T-cells were investigated by the E rosette assay, PHA stimulation, allogeneic MLC and CML responses, in a group of 100 healthy aged people over 70 years old, and compared to young control individuals less than 45 years old. No major difference was found between the two groups, except for PHA stimulation which was significantly reduced in old individuals when low mitogen concentration was used. These observations suggest that only some T cells subsets are affected by ageing, without modification of the total T lymphocyte number. Contrarily, the phagocytic activities of polymorphonuclear cells assessed in a group of 38 aged people were dramatically decreased, using either the NBT test or a direct phagocytosis assay.

Aged↗
PubMed1981

Evaluation of T cell subsets in myasthenia gravis using anti-T cell monoclonal antibodies.

Functional T cell subsets have been evaluated in the peripheral blood of patients with myasthenia gravis using monoclonal anti-T cell antibodies and a suppressor cell assay based on the suppression of the mixed-lymphocyte reaction by concanavalin A-activated lymphocytes. A significant decline of suppressor cells was found in a large proportion of patients, both by direct count using the anti-suppressor-cytotoxic T cell antibody (OKT8) and by the suppressor assay. Patients also showed an increase in immature T cells defined by their simultaneous reaction with the anti-helper cell (OKT4) and anti-suppressor cell (OKT8) antibody. Thymectomy tended to enhance the deficit in suppressor cells, and to induce the disappearance of double-labelled cells.

Adolescent↗
PubMed1981

The use of monoclonal anti-T cell antibodies to study T cell imbalances in human diseases.

Monoclonal antibodies are now available to evaluate human T cell subsets by direct counting using indirect immunofluorescence analysis. The critical use of these antibodies has already permitted the delineation of the T cell imbalances present in a number of immunologically mediated diseases such as autoimmune haemolytic anaemia, chronic active hepatitis, myasthenia gravis, glomerulonephritides, multiple sclerosis, leprosy, or immunodeficiency syndromes. The potential diagnostic and therapeutic application of this new methodology are emphasized.

Aging↗
PubMed1981

Thymoma with hypersecretion of thymic hormone.

A 78-yr-old patient presented with a malignant thymoma with a predominance of epithelial cells. Lymphocyte markers (E rosettes, T-cell-specific xenoantigen and surface Ig) and electrophoretic studies showed that more than 95% of the peripheral blood lymphocytes were T cells. High levels of circulating thymic factor were repeatedly found before treatment (irradiation and chemotherapy). It is suggested that inappropriate hypersecretion of thymic hormone is responsible or can contribute to the immunological abnormalities found in this patient.

Aged↗