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F Rousset

Publications and source records attributed to F Rousset.

100 records · Page 6Linked to original sources
PubMed1988

Human recombinant interleukin 4 induces normal B cells to produce soluble CD23/IgE-binding factor analogous to that spontaneously released by lymphoblastoid B cell lines.

Surface-labeled Epstein-Barr virus (EBV)-transformed lymphoblastoid RPMI 8866 cells release in their supernatant a radiolabeled 25-kDa polypeptide which reacts with the Fc epsilon RL/CD23-specific monoclonal antibody (mAb) 25 and which binds to IgE but not IgG (IgE BF/sCD23). IgE BF/sCD23 had an isoelectric point of 4.5-5.0. The reactivity of mAb 25 with IgE BF/sCD23 allowed us to set up a radioimmunoassay for detection of IgE BF/sCD23 in cell culture supernatants. Supernatants from Fc epsilon RL/CD23+ cell lines were found to contain IgE BF/sCD23. Addition of human recombinant interleukin 4 (IL 4) to normal human B cells cultures induced the production of IgE BF/sCD23. Activation of B cells with anti-IgM antibody coupled to beads enhanced the IL 4-induced production of IgE BF/sCD23 when compared to nonactivated B cells. This correlates with the finding that anti-IgM antibody-activated B cells cultured with IL 4 express more Fc epsilon RL/CD23 than B cells cultured with IL 4 alone. The biochemical characteristics of radiolabeled IgE BF/sCD23 immunoprecipitated by mAb 25 from the supernatants of normal B cells cultured with IL 4 were identical to those of the IgE BF/sCD23 isolated from EBV-transformed cell line supernatants. Addition of interferon-gamma to B cells cultured with IL 4 strongly decreased the level of IgE BF/sCD23 in culture supernatants correlating with the observed decrease of Fc epsilon RL/CD23 on B cell surface. These data demonstrate that normal human B cells cultured in the presence of IL 4 produce an IgE-binding factor (sCD23) biochemically and antigenically equivalent to that spontaneously produced by EBV-transformed lymphoblastoid cell lines.

B-Lymphocytes↗
PubMed1988

Interleukin 5 enhances interleukin 4-induced IgE production by normal human B cells. The role of soluble CD23 antigen.

Interleukin 4 (IL 4)-induced IgE production by peripheral blood lymphocytes and tonsil cells from normal donors was enhanced in a dose-dependent fashion by IL 5. IL 5 tested alone was not effective. The synergistic effects of IL 5 were most pronounced at suboptimal IL 4 concentrations, whereas at saturating IL 4 concentrations (200-300 U/ml), IL 5 had no effect. Interferon-gamma (IFN-gamma) and F(ab')2 fragments of monoclonal antibody 25 directed against the CD23 antigen, that blocked IL 4-induced IgE synthesis, also inhibited the production of IgE in the presence of combinations of IL 4 and IL 5, indicating that IL 5 potentiates the activation pathway through which IL 4 induces IgE production. In contrast, IL 4 (50 U/ml) blocked IL 5-induced IgA synthesis. IL 5 was ineffective in inducing the release of soluble CD23 (sCD23), but in the presence of IL 4 an enhanced release of sCD23 was observed, provided IL 4 was present at suboptimal concentrations. IFN-gamma completely blocked sCD23 release induced by IL 4 and IL 5. These results demonstrate that there is a strong quantitative correlation between sCD23 release and induction of IgE synthesis. sCD23 fraction-correlation between sCD23 release and induction of IgE synthesis. sCD23 fractionated from the Epstein-Barr virus-transformed B cell line RPMI 8866 was ineffective in inducing IgE production. However, sCD23 acted synergistically with suboptimal concentrations of IL 4. sCD23 did not modulate the IgE response at saturating concentrations of IL 4. Collectively, these data indicate that sCD23 plays an important regulatory role in the modulation of IL 4-induced IgE synthesis mediated by IFN-gamma and IL 5.

Adjuvants, Immunologic↗
PubMed1988

Estrogen and progesterone receptors in some human myeloma cell lines and murine hybridomas.

The control of immune responses by sex hormones is well documented but the effect of sex hormones on lymphoid cell subsets is poorly understood. We have investigated the expression of receptors for androgens (AR), estradiol (ER) and progesterone (PR) by human cell lines of the B lymphocyte lineage and by murine myeloma or hybridomas. AR, ER and PR were determined by cytosol and nuclear binding assays. Eleven human lymphoblastoid cell lines obtained by in vitro infection of blood or tonsil B cells with Epstein-Barr Virus (EBV) B95, did not express AR or ER. Similarly, 10 Burkitt's lymphoma cell lines were AR, ER and PR negative with the exception of the pre-B RAJI cells which bear AR. Among 13 cell lines derived from patients with multiple myeloma none expressed AR but five were found to bear ER (20-164 fmol/mg DNA or 5-10 fmol/mg protein). Four of the latter group also bear PR (86-450 fmol/mg DNA). Two mouse hybridomas out of seven tested were ER and PR positive. The MOPC 315 myeloma expressed ER but not PR. The possible functional role of these sex hormone binding sites in cell proliferation and immunoglobulin secretion deserves further investigation.

Animals↗
PubMed1988

IgE production by normal human lymphocytes is induced by interleukin 4 and suppressed by interferons gamma and alpha and prostaglandin E2.

The effect of human recombinant interleukin 4 (IL-4) on antibody production by normal peripheral blood mononuclear cells enriched for B cells was investigated. IL-4 preferentially induced IgE synthesis in vitro. In addition, a low induction of IgG production was observed, whereas IL-4 had no effect on IgA and IgM synthesis. The IL-4-induced IgE production by B cells required T cells and monocytes but was specifically inhibited by an anti-IL-4 antiserum indicating that, although IL-4 acts indirectly, it is responsible for the induction of IgE synthesis. IL-4-induced IgE production was blocked in a dose-dependent way by interferon gamma (IFN-gamma), interferon alpha (IFN-alpha), and prostaglandin E2. IFN-gamma also inhibited IL-4-induced IgG production. These inhibitory effects of IFN-gamma and IFN-alpha on IgE production cannot be attributed to toxic effects since IFN-alpha induced IgM production in the presence of IL-4, whereas IFN-gamma was ineffective in inhibiting IgG production induced by IL-2. IFN-gamma, IFN-alpha, and prostaglandin E2 also inhibited IL-4-induced expression of the low-affinity receptor for the Fc portion of IgE (CD23) on B cells, indicating that there is an association between CD23 expression and IL-4-induced IgE production. This theory was supported by the finding that IL-4-induced IgE production was inhibited by F(ab')2 fragments of an anti-CD23 monoclonal antibody.

Antibodies, Monoclonal↗
PubMed1987

Human recombinant interleukin 4 induces Fc epsilon receptors (CD23) on normal human B lymphocytes.

Human rIL-4 is able to induce the expression of low-affinity receptors for IgE (Fc epsilon RL/CD23) on resting B lymphocytes, as determined by the binding of either the anti Fc epsilon RL/CD23-specific mAb 25 or IgE. Stimulation of B cells with insolubilized anti-IgM antibody increases the number of cells expressing Fc epsilon RL/CD23 upon culturing with IL-4 and enhances the level of Fc epsilon RL/CD23 expression on these cells. Fc epsilon RL/CD23 induction is specific for IL-4 since IL-1 alpha, IL-2, IFN-gamma, B cell-derived B cell growth factor (BCGF), and a low-molecular-weight BCGF were ineffective. IFN-gamma strongly inhibited the induction of Fc epsilon RL/CD23 by IL-4.

B-Lymphocytes↗
PubMed1986

Studies of EBV-lymphoid cell interactions in two patients with the X-linked lymphoproliferative syndrome: normal EBV-specific HLA-restricted cytotoxicity.

Two X-linked lymphoproliferative syndrome (XLP) patients with the hypogammaglobulinemia phenotype were investigated at a time remote from their primary infection with the Epstein-Barr virus (EBV). The lymphoblastoid cell lines derived from these patients expressed the phenotypic markers characteristic of normal mature B lymphocytes and produced normal levels of immunoglobulins (Ig). These observations imply that at least some of their B cells are phenotypically normal. The natural killer (NK) activity of the two patients was low. In one patient, activated lymphocyte killer (ALK) activity was inefficient. These two XLP patients expressed a normal EBV-specific, HLA-restricted cytotoxic activity. It thus appears, from the present findings and those in cases published previously (6/11 patients expressing normal EBV-specific cytotoxic activity), that the notion of poor specific T cell memory for EBV may not be as pivotal ass suggested or, alternatively, that this defect may not be common in hypogammaglobulinemic survivors.

Adolescent↗
PubMedDate not supplied

Generation and characterization of a human monoclonal autoantibody that acts as a high affinity interleukin-1 alpha specific inhibitor.

Interleukin-1 (IL-1) defines two polypeptides, IL-1 alpha and IL-1 beta, that possess a wide spectrum of biological effects. Two natural antagonists of IL-1 action have been characterized: the IL-1 receptor antagonist (IL-1Ra) and a soluble form of the type II IL-1 receptor. Neutralizing autoantibodies to IL-1 alpha have also been detected in sera of healthy individuals and patients with autoimmune or inflammatory diseases. To characterize such antibodies molecularly, we attempted to generate B cell clones producing anti-IL-1 alpha human monoclonal antibody (HuMAb) by combining Epstein-Barr virus-immortalization and CD40-activation of B lymphocytes from individuals with circulating anti-IL-1 alpha. We describe herein the generation and properties of a natural IgG4/kappa anti-IL-1 alpha monoclonal autoantibody, HuMAb X3, that bound specifically to human IL-1 alpha, but not to IL-1 beta and IL-1Ra, with a high affinity (Kd = 1.2 x 10(-10)M). HuMAb X3 inhibited IL-1 alpha binding to IL-1 receptors and neutralized biological activities of both recombinant and natural forms of IL-1 alpha. A recombinant form of HuMAb X3 was found to display identical specific IL-1 alpha antagonism. The presence of somatic mutations within X3 variable regions suggests an antigen-driven affinity maturation. This study extends the demonstration of the presence of high affinity neutralizing anti-IL-1 alpha autoantibodies that can function as a third type of IL-1 antagonist.

Amino Acid Sequence↗
PubMedDate not supplied

Contact sensitizers decrease 33D1 expression on mature Langerhans cells.

Langerhans cells play a critical role in allergic contact hypersensitivity. In vivo, these cells capture xenobiotics that penetrate the skin and transport them through the lymphatic vessels into regional lymph nodes for presentation to T cells. During this migration step, Langerhans cells become mature dendritic cells according to their phenotype and their high immunostimulatory capacity. In vitro, when isolated from the skin and cultured for 3 days, Langerhans cells undergo similar phenotypic and functional maturation. In this study, the capacity of sensitizers, irritants and neutral chemicals to modulate the surface marker expression and morphology of pure mature murine Langerhans cells in vitro was examined. Contact with 4 sensitizers (2,4-dinitrobenzenesulfate, 4-ethoxymethylene-2-phenyl-2-oxazolin-5-one, p-phenylenediamine, mercaptobenzo-thiazole) resulted in a rapid, specific, marked fall in 33D1 expression, a murine specific dendritic cell marker. No effect was observed with 2 neutral chemicals (sodium chloride, methyl nicotinate) or 2 irritants (dimethyl sulfoxide, benzalkonium chloride). Nevertheless, sodium lauryl sulfate, a very irritant detergent, altered morphology and down-regulated all membrane markers. These preliminary data suggest that in vitro modulation of 33D1 expression by strong sensitizers may be an approach to the development of an in vitro model for the identification of chemicals that have the potential to cause skin sensitization and to distinguish them as far as possible from irritants.

Animals↗