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J M Pleau

Publications and source records attributed to J M Pleau.

At least 19 recordsLinked to original sources
PubMed2000

Phase I clinical trial with IL-2-transfected xenogeneic cells administered in subcutaneous metastatic tumours: clinical and immunological findings.

Various studies have emphasized an immunodepression state observed at the tumour site. To reverse this defect and based upon animal studies, we initiated a phase I clinical trial of gene therapy in which various doses of xenogeneic monkey fibroblasts (Vero cells) genetically engineered to produce human IL-2 were administered intratumorally in 8 patients with metastatic solid tumours. No severe adverse effect was observed in the 8 patients analysed during this clinical trial even in the highest dose (5 yen 107 cells) group. This absence of toxicity seems to be associated with rapid elimination of Vero-IL-2 cells from the organism. Indeed, exogenous IL-2 mRNA could no longer be detected in the peripheral whole blood 48 hours after Vero-IL-2 cell administration. In addition, we did not find any expression of exogenous IL-2 mRNA in post-therapeutic lesions removed 29 days after the start of therapy. A major finding of this trial concerns the two histological responses of two treated subcutaneous nodules not associated with an apparent clinical response. The relationship between local treatment and tumour regression was supported by replacement of tumour cells by inflammatory cells in regressing lesions and marked induction of T and natural killer cell derived cytokines (IL-2, IL-4, IFNg ...) in post-therapeutic lesions analysed 28 days after the start of Vero-IL-2 administration. Gene therapy using xenogeneic cells as vehicle may therefore present certain advantages over other vectors, such as its complete absence of toxicity. Furthermore, the in vivo biological effect of immunostimulatory genes, i.e IL-2-, may be potentiated by the xenogeneic rejection reaction.

Adenocarcinoma↗
PubMed1998

Pancreatic hormone expression in the murine thymus: localization in dendritic cells and macrophages.

The expression of preproinsulin (ppIns), proglucagon, prosomatostatin, and propancreatic polypeptide was investigated in thymic extracts, thymic cells, and thymic cell lines from C57BL/6 mice by RT-PCR. The expression of pancreatic hormones was similar in thymic extracts taken from neonatal and 2-, 4-, and 8-week-old animals, but was decreased in 20-week-old animals. Pancreatic hormone expression was not observed in mouse liver, salivary gland, or spleen. Analysis of thymic cell populations revealed a 10- to 20-fold enrichment in expression of all hormones in low buoyant density cells. No expression was detected in high buoyant density cells (predominantly thymocytes) or in thymic epithelial cell lines, primary cultures of epithelial cells, or peripheral macrophages. In addition, immunoreactive insulin, measured by specific RIA, was detectable in the low buoyant density population, but not in high buoyant density cells. The enriched cell population was depleted of contaminating lymphocytes and sorted based on reactivity to the cell surface markers F4/80 (macrophage) or N418 (dendritic cells). Cells gated for N418 demonstrated expression for ppIns, but not the other pancreatic hormones. Conversely, expression for proglucagon, prosomatostatin, and propancreatic polypeptide, but not ppIns, was detected in F4/80-gated cells. Our data indicate that pancreatic endocrine hormones are differentially expressed by dendritic cells and macrophages in a normal mice.

Animals↗
PubMed1997

Ontogeny of glutamic acid decarboxylase gene expression in the mouse pancreas.

Using two RT-PCR quantitative assays, we measured the pancreatic expression of the two isoforms of glutamic acid decarboxylase in the foetus, newborn and 14-, 21- and 35-day-old male and female NOD and C57BL/6 mice. In the C57BL/6 mouse, GAD 67 pancreatic expression is stable; in NOD mice, GAD 67 expression is similar to that found in control mice, except at 5 weeks of age, when pancreatic GAD 67 expression is about 2.5 times higher than in C57BL/6 mice. The pancreatic expression of GAD 65 is under the detection limit of the assay until 5 weeks of age. The overexpression of GAD 67 characterized in pancreas from 5-week-old NOD mice could be the result of beta cell hyperactivity, previously reported in this mouse strain.

Animals↗
PubMed1996

Glutamic acid decarboxylase (GAD 67) gene expression in the pancreas and brain of the nonobese diabetic mouse.

A quantitative PCR was developed to measure GAD 67 mRNA levels in pancreas from NOD mice. Two nonautoimmune mouse strains were used as controls. An internal standard, rat GAD 67 mRNA, was prepared to quantify the reaction. In NOD mice GAD 67 expression in the pancreas was in the order of 2 x 10(6) molecules/microgram of total RNA; this expression was five times less in the two control mouse strains, whatever the age. The overexpression of GAD 67 characterized in the NOD mouse could be restricted to the pancreas since similar analysis performed in mouse brain did not reveal a large difference between the three mouse strains studied.

Aging↗
PubMed1996

Gene expression of pancreatic glutamic acid decarboxylase in the nonobese diabetic mouse.

The 65 kDa isoform of glutamic acid decarboxylase (GAD 65) is an autoantigen implicated in type I diabetes. We have developed a quantitative PCR method to measure GAD 65 mRNA in the pancreas of nonobese diabetic (NOD) mice. Two other nonautoimmune mouse strains were used as controls. In all mice, pancreatic GAD 65 expression declined with age. In 5-week-old NOD mice, a clear difference was detected between males and females. This sexual dimorphism may explain the absence of tolerance to GAD 65 in the NOD female which could contribute to autoimmune destruction of beta cells in the pancreas and subsequent development of diabetes.

Animals↗
PubMed1996

Interleukin-1 effect on glycemia in the non-obese diabetic mouse at the pre-diabetic stage.

Cytokines, particularly interleukin 1 (IL-1) and tumor necrosis factor, are known to induce hypoglycemia in normal rodents or different experimental models of type II diabetes. We investigated, at the pre-diabetic stage, the effect of short-term administration of murine recombinant interleukin-1 alpha (mrIL-1 alpha) on the levels of glucose, insulin and corticosterone in the non-obese diabetic (NOD) mouse, a spontaneous model of type I diabetes. Two-month-old, pre-diabetic NOD mice of both sexes were insensitive to mrIL-1 alpha (12.5 and 50 micrograms/kg) 2 h after administration, the time at which the maximal decrease (around 50%) was observed in the C57BL/6 mouse strain. Kinetic studies however showed that mrIL-1 alpha lowered glycemia in both sexes of NOD mice, but the effect was limited and delayed. In the NOD and C57BL/6 strains, mrIL-1 alpha had no influence on insulin levels in females, but significantly increased them in males (P < 0.0001). Castration of NOD males abrogated the stimulatory effect of mrIL-1 alpha on insulin secretion. Corticosterone secretion was stimulated by mrIL-1 alpha in both sexes of NOD and C57BL/6 mice, and this effect was faster and greater in NOD females than in C57BL/6 females. The incomplete hypoglycemic response to mrIL-1 alpha in females may be attributed to the anti-insulin effect of glucocorticoids, an effect which can be demonstrated when mrIL-1 alpha is administered to adrenalectomized animals or when mrIL-1 alpha is administered together with the glucocorticoid antagonist RU38486. In NOD males, in contrast, glucocorticoids did not play a major role in the limited hypoglycemic response to mrIL-1 alpha, since RU38486 and adrenalectomy were not able to unmask a hypoglycemic effect. Moreover, NOD mice of both sexes were less sensitive than C57BL/6 mice to the hypoglycemic effect of insulin (2.5 U/kg), which suggests some degree of insulin-resistance in NOD mice. With regard to the effect of IL-1 on NOD mouse glycemia, therefore, these results suggest that glucocorticoids and/or androgens, according to the animal's sex, may induce a state of insulin-resistance.

Adrenalectomy↗
PubMed1995

Prevention of autoimmune diabetes in nonobese diabetic female mice by treatment with recombinant glutamic acid decarboxylase (GAD 65).

The nonobese diabetic (NOD) mouse spontaneously develops insulin-dependent diabetes (IDDM or type I diabetes), resulting from T-lymphocyte-mediated destruction of pancreatic beta cells. This autoimmune phenomenon includes mononuclear cell infiltration of the islets of Langerhans (insulitis) and the presence of circulating autoantibodies. The specificity of the autoantibodies and of the autoreactive T cells was investigated and several autoantigens were proposed, in particular glutamic acid decarboxylase (GAD). This enzyme exists in two forms (GAD 65 and GAD 67) encoded by two independent genes. To explain the role of GAD in type I diabetes, we prepared recombinant rat GAD 65 as fusion protein, produced in an Escherichia coli expression system, and we treated NOD female mice from 4 to 7 weeks of age by repeated intraperitoneal injections of 5 micrograms fusion protein (3 injections per week); control groups received the fusion partner, maltose binding protein (MBP) or dissolving agent (NaCl 0.9%). We investigated two parameters, the degree of insulitis 5 weeks after the last injection and the overall incidence of the disease. Histological examination of the pancreata from GAD-treated mice revealed a significant reduction in the severity of insulitis compared with the two control groups. Furthermore, we observed that the time of onset and the frequency of diabetes in NOD females injected with GAD fusion protein differed significantly from the control groups receiving MBP or NaCl (P < 0.0001). These results show that a 3-week treatment of NOD female mice starting at 4 weeks of age protects them from diabetes, again emphasizing the crucial role of GAD as autoantigen in type I diabetes.

ATP-Binding Cassette Transporters↗
PubMed1995

Quantitative analysis of glutamate decarboxylase (GAD 65) gene expression in NOD mouse pancreas.

Glutamate decarboxylase (GAD), especially the GAD 65 isoform, is a major autoantigen in autoimmune diabetes. To determine the role of GAD 65 in the pathogenesis of the disease, we developed a quantitative PCR method allowing to establish the absolute number of GAD 65 mRNA molecules expressed in pancreas of male and female non-obese diabetic (NOD) mice at 5 weeks of age, in comparison of the 2 non autoimmune mouse strains. It appeared that pancreatic expression of GAD was similar in the 3 strains (around 30,000 molecules/micrograms total RNA) in males. However, in the NOD mouse, sexual dimorphism was observed with low GAD 65 expression in the female known to show higher incidence of the disease than the male. This finding could contribute to the absence of GAD 65 tolerance in the female and suggests an hormonal control of GAD 65 gene expression.

Animals↗
PubMed1990

A new radioimmunoassay for the thymic peptide thymulin, and its application for measuring thymulin in blood samples.

A new, specific and sensitive radioimmunoassay, using a polyclonal antiserum raised in rabbits, is described for quantitating plasma thymulin. As little as 300 fg thymulin can be measured in one assay tube. The method has been used to measure thymulin in human blood (umbilical vessel blood, 2191 +/- 123 fg/ml; children and adults up to the age of 20 years, 1499 +/- 119 fg/ml; and adults between 21-65 years, 371 +/- 18 fg/ml). There is a highly significant decrease within these three groups (P less than 0.001 by one way analysis of variance). Also plasma thymulin levels were determined in rats (601 +/- 127 fg/ml) and in pooled plasma samples from mice (638 +/- 56 fg/ml). No thymulin was detected in plasma obtained from nude rats, nude mice and thymectomised mice. These results show that the radioimmunoassay described here is a useful quantitative tool for measuring plasma thymulin that will have applications in basic, applied and clinical research.

Animals↗
PubMed1985

Thymulin.

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Animals↗
PubMed1984

Studies on the zinc binding site to the serum thymic factor.

Gel filtration studies of 65Zn2+ binding to thymulin show that the nonapeptide can strongly bind one zinc metal ion. At pH 7.5, thymulin binds one zinc ion with an apparent affinity constant Kd of 5 +/- 2 X 10(-7) M. Binding is pH dependent. No binding is observed below pH 6.0. Ga3+, Al3+, Mn2+ and Cu2+ can compete with the binding of Zn2+ at pH 7.5. A good correlation between the competition potencies of metal ions used and the extent of biological activity of thymulin in the presence of these metal ions in an in vitro rosette assay is observed. Structural analogs of thymulin and non-thymulin-related peptides were used in a gel filtration technique to tentatively define the nature of amino acids present in the Zn2+-binding site of thymulin.

Binding Sites↗
PubMed1983

Interaction of thymopoietin peptides with the specific receptor of facteur thymique serique (FTS).

The capacity of ubiquitin (UB) and thymopoietin II (TP) related peptides (TP 5 and TP 13) to interfere with the specific binding of [3H]FTS on intact 1301 cells or on 1301 plasma membrane preparations was studied. All 3 peptides significantly inhibited the binding of [3H]FTS to its receptors on intact 1301 cells at concentrations 20 to 100 times higher than FTS itself. Conversely, none of the 3 peptides provided a significant inhibition of the specific [3H]FTS binding to plasma membrane preparations of 1301 cells compared to control peptides. These contrasted results suggest that TP-related peptides and, to a lesser degree, UB may share the same target cells with FTS and interfere with FTS effects on T cells, but this interaction probably does not involve direct high affinity binding to the FTS receptors.

Animals↗
PubMed1982

High affinity binding sites on plasma membrane obtained from the lymphoblastoid cultured 1301 cell line for highly radioactive serum thymic factor.

The interaction of the synthetic serum thymic factor (FTS, facteur thymique sérique) with a plasma membrane preparation of human T lymphocytes from the lymphoblastoid T cell line 1301 was studied using 3H-labelled FTS (specific activity 120 Ci/mmol). The binding is temperature dependent and function of the concentration of both 3H-labelled FTS and membrane proteins. At 37 degrees C, using 1 nM of 3H-labelled FTS as steady state is observed within 80 min. The binding is reversible, specific and saturable. Scatchard analysis reveals the existence of at least two binding sites with respective Kd of the order of 0.516 +/- 0.2 nM and 110 +/- 27.8 nM with concentration of 0.186 +/- 0.045 pmol and 2.026 +/- 0.367 pmol per mg of membrane protein.

Binding Sites↗
PubMed1982

Monoclonal antibody against the serum thymic factor (FTS).

Hybrid cell lines secreting antibodies specific for synthetic serum thymic factor (FTS) were prepared by cell fusion and cloning techniques. Spleen cells from BALB/c mice immunized with BSA-coupled FTS were fused with P3-x63-Ag8.653 myeloma cells. Antibodies produced by these hybrids were screened in vitro for their ability to absorb the activity of synthetic FTS in a rosette assay and in vivo for their capacity to induce the disappearance of endogenous FTS. Subsequently, the clones selected were transferred intraperitoneally into BALB/c mice. Ascitic fluid was produced and used as a source of antibody. The monoclonal antibody was shown to bind specifically to thymic reticulo-epithelial cells, using an indirect immunofluorescence technique. Furthermore, once injected into normal mice, the antibody induced the disappearance of FTS from the serum and modified the azathioprine sensitivity of spleen rosette-forming cells for more than 3 weeks.

Animals↗
PubMed1982

Identification of FTS (facteur thymique serique) on thymus ultrathin sections using monoclonal antibodies.

Using a new immunoelectromicroscopical technique, this study confirms the localization of the 'facteur thymique sérique' (FTS) in the reticulo-epithelial cells of mouse thymus. The use of anti-FTS monoclonal antibodies on ultrathin sections for electron microscopy reveals FTS in cytoplasmic vacuoles, labelling density depending on the density of the vacuolar content. The successful application of this technique opens the way to its use for double-immunolabelling.

Animals↗
PubMed1982

Location of FTS (facteur thymique sérique) in the thymus of normal and auto-immune mice.

This study was concerned with the in situ localization of facteur thymique sérique (FTS) by immunoelectron microscopy in the thymus of normal C57BL mice and aged auto-immune SWAN mice. Normal young mice have anti-FTS antibodies fixed specifically on the floccular material present in the cytoplasmic vacuoles of epithelial cortical and medullary cells. In aged auto-immune SWAN mice the anti-FTS antibodies show an activity only in the granules present in the vacuoles or free in the cytoplasm of epithelial cells. The floccular material is not labelled by the same antibodies. FTS positive granules show a repetitive structure which is characteristic of crystalline protein formations. The presence of FTS in the granules of cells confirm the hypothesis of FTS storage in the cytoplasm of epithelial cells in vivo during the auto-immune process.

Animals↗
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↗