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Biomedical subjects

G Cordier

Publications and source records attributed to G Cordier.

At least 55 records · Page 3Linked to original sources
PubMed1984

An anti-lymphocyte monoclonal antibody (HB8) which cross reacts with human dermal elastic fibers.

A monoclonal antibody (MoAb) was selected during a fusion aimed at the preparation of antibodies specific for human T lymphocytes. This antibody reacted against all lymphocytes, but was not specific for the lymphoid lineage because it also detected monocytes, granulocytes and platelets. On skin sections it was found to stain specifically the microfibrillar component of the elastic fibers. This observation illustrates the unexpected specificities often found when making MoAb and, although its significance is still unexplained, provides a unique tool having potential application for anatomy, histopathology, comparative biology and vascular pathology.

Animals↗
PubMed1984

Detection of OKT6-positive cells (without visible Birbeck granules) in normal peripheral blood.

The specificity of a monoclonal antibody (OKT6) for peripheral blood mononuclear cells was examined by indirect immunofluorescence and ultrastructural immunogold labelling. Some rare peripheral blood mononuclear cells (approximately 1%) expressed T6 antigen on their membrane surface, as determined by light microscopy and cytofluorometry. Electron microscopic examination of immunogold-labelled cells revealed that OKT6-positive cells were dendritic, lacking the Birbeck granules and expressed variable density of the membrane T6 antigen. The relationship of such cells with Langerhans' cells is discussed.

Adolescent↗
PubMed1984

Quantitative evaluation of two distinct cell populations expressing HLA-DR antigens in normal human epidermis.

HLA-DR antigens are expressed only by Langerhans cells (LC) and indeterminate cells (IC) in normal human epidermis. Indirect immunofluorescence and ultrastructural immunogold labelling were used to study the HLA-DR expression by means of two anti-DR monoclonal antibodies (MCA). Freshly dispersed DR-positive epidermal cells expressed different densities of DR antigens on their membrane surface. Approximately 25% of DR-positive cells were strongly labelled by anti-DR-MCA and 75% were weakly stained. After 18 h in complete culture medium before labelling no significant difference in these percentages was observed. The lymphoid-like LC-enriched cells obtained by Ficoll-Hypaque centrifugation also had two populations of DR-positive cells: strongly labelled cells (30.8%) and weakly labelled cells (69.2%). DR-positive cells may be divided into two types according to the density of DR sites on their cell membrane: (I) type DR+ shows weak surface labelling by gold particles (8.8 +/- 3.0 gold particles/micron) and has cytoplasmic Birbeck granules, identifying such cells as typical Langerhans cells; (2) type DR shows strong membrane immunogold labelling (38.9 +/- 4.6 gold particles/micron) and may or may not contain Birbeck granules. The gold particles bound to the cell membrane were used to quantify the number of HLA-DR sites expressed on each cell type: 1 X 10(5) sites on DR+ cells and 5 X 10(5) on DR cells.

Antibodies, Monoclonal↗
PubMed1984

Increased DNA and/or RNA content of synovial fluid cells in rheumatoid arthritis: a flow-cytometry study.

Flow-cytometry studies of DNA and RNA content were carried out in acridine orange-stained synovial fluid lymphocytes from 11 patients presenting with classical or definite rheumatoid arthritis. Monoclonal antibodies were used to detect specific T cell surface antigens (OKT3, OKT4, OKT8) and antigens associated with lymphocyte activation (OKIa 1, OKT10). T3 positive cell percentages were comparable to those of normal blood, although T4/T8 ratios were decreased in 4 out of 5 cases, and HLA-DR positive cells increased. Six out of 11 patients showed percentages of dividing cells varying from 2.2 to 7.2% as compared with less than 1% in the other patients and in normal blood. Nondividing cells were characterised by an increase in their RNA content compared with normal blood. A greater increase of RNA content was observed in patients with lower percentages of dividing cells, suggesting a G1/S block. Changes in cellular DNA and/or RNA contents provide a valuable parameter of lymphocyte activation, not necessarily linked to the expression of differentiation antigens by activated cells.

Adolescent↗
PubMed1984

[Simultaneous determination of cellular DNA and proteins by cytofluorimetry. Application to acute leukemia in adults].

DNA and proteins of ethanol fixed cells are simultaneously analysed by cytofluorimetry in 35 cases of adult acute leukemias. DNA is coloured by propidium iodide and proteins by FITC. These technics allow to know the GO/G1, S, G2 + M cell-cycle phases and the protein cell content for each phase. We also can evaluate the fraction of low protein content cells (LPC fraction) that seems to be the GO and early G1 fraction. A good correlation exists between the percentage of S phase cells and the LPC fraction. This parameter, because of its important dispersion, must have a better discriminating value than S phase, especially for the prognosis analysis. Furthermore acute myeloid leukemias have a protein content that varies with the cytological maturation. Therefore, P1 + FITC colorations would give quantitative criteria for the acute leukemias cytological analysis and their prognostic valuation.

Adolescent↗
PubMed1984

Monoclonal anti thymic cell antibodies detecting epidermal cells.

Two monoclonal antibodies were obtained from a fusion following immunization with human thymic cells. BL6 reacted with an antigen present on 80% of thymocytes found in the cortex, but absent from all other circulating or non circulating T or B lymphocytes. It immunoprecipitated an antigen of 49 Kd heavy chain with a small 12 Kd subunit. BL6 also reacted with dendritic cells of the epidermis identified as Langerhans cells carrying histocompatibility class II antigens and possessing Birbeck granules. The second antibody, BL7, did not stain thymocytes, but reacted with a cytoplasmic antigen of certain thymic epithelial cells. In skin sections, BL7 detected a cytoplasmic antigen of the keratinocytes of the basal cell layer. These cross reactivities between skin and thymic cells are discussed in view of a possible functional similarity between the two tissues.

Adult↗
PubMed1984

[Cytofluorometric study of the cell cycle and various lymphocyte differentiation membrane antigens in the synovial fluid in rheumatoid polyarthritis].

Synovial fluid lymphocytes were studied by cytofluorometry in 11 patients with classical or definite rheumatoid arthritis. This method allowed the study of the cellular cycle after acridine orange staining and of membrane antigens, expressed by normal and/or activated lymphocytes, which were demonstrated by using various monoclonal antibodies (OKT3, OKT4, OKT8, OKIa1, OKT10). The OKT4/OKT8 ratio was decreased in 4 out of 5 cases and the percentage of HLA DR + cells was clearly increased. In 6 out of the 11 patients, the percentage of dividing cells varied from 2.2 to 7.2 and was less than 1 in the others as in normal blood lymphocytes. Increase in cellular RNA content characterized the non dividing cells. The most elevated values of the cellular RNA content were observed in patients who had the smallest percentage of dividing cells, suggesting that the cellular cycle was stopped between the G1 and S phases. Study of the cellular cycle may reveal a lymphocyte activation parameter which could be unrelated to the expression of differentiation membrane antigens.

Adolescent↗
PubMed1984

Morphofunctional modifications associated with the inhibition by estradiol of MtTF4 rat pituitary tumor growth.

The MtTF4 pituitary tumor has been induced in Fischer rats by chronic estrogen administration. Recently, we reported that sustained pharmacological treatment of Fischer rats with 17 beta-estradiol inhibited the growth of the MtTF4 tumor transplanted s.c. The present work describes the associated morphofunctional changes occurring in the tumor during 17 beta-estradiol inhibition. It is shown that a 7-day 17 beta-estradiol treatment resulted in an increase of the surface area of cells, nuclei, nucleoli, Golgi complexes, and rough endoplasmic reticulum and an increase in the number of euchromatin-rich nuclei. Flow cytometry analysis of DNA distribution suggested that estradiol affects the cell progression through the early S phase. The ratio of RNA to DNA increased significantly, reflecting cell hypertrophy. Moreover, there was a significant increase in tumor prolactin concentration and a marked enhancement in the intensity of the immunocyto-chemical reaction with rat prolactin antiserum. On the other hand, cell mitoses were dramatically decreased. These morphofunctional changes indicate that the inhibition of the tumor growth by estradiol is accompanied by an evolution of the tumor cell population towards a more differentiated state. However, it cannot be decided whether 17 beta-estradiol induces a shift from a proliferative state to a differentiated state or whether 17 beta-estradiol treatment results in a selection of a subpopulation of tumor cells that are slow growing and more differentiated.

Animals↗
PubMed1983

[Markers of lymphocyte activation in interstitial pulmonary disease].

A lymphocytic alveolitis is a common stage in a number of types of interstitial pneumonia where the lymphocytes accumulate in the alveoli and play a major pathogenic role by the regulation or activation of the inflammatory reaction, controlling the outcome either to healing, chronicity or fibrosis. A study of lymphocytes obtained by broncho-alveolar lavage enables the study of different parameters whose functional value is discussed from information derived form in vitro models. These models show the need for activating signals acting in a sequential manner on cells whose function and mode of response are remarkably varied. Three successive phases may be defined during activation: first a "membrane" stage with changes in the lipid (in the metabolism of arachidonic acid) and kinetic framework, a second phase corresponds to the beginning of "blastic transformation" with the production of lymphocytes, an increase in the protein content and RNA (phase G1), then a third stage of DNA synthesis (phase S-G2) preceding cell division; it is necessary to have new markers of differentiation. The joint study of the phases of cell cycles and the antigenic expression of differentiation, identified by monoclonal antibodies within a heterogeneous population nowadays benefit from techniques of cytofluorimetry. The methods combined with a measure of mediators produced (interleukins) or the non-specific markers of activation by macrophages ought to lead to a definition of initial stages of the clinical immunology of alveolitis. Finally these methods permit the development of cellular immunopharmacology which to open the possibilities of new forms of treatment.

DNA↗
PubMed1983

[Criteria for T-lymphocyte activation in alveolitis].

A lymphocytic alveolitis is a common stage in a group of interstitial pulmonary disorders, where the lymphocytes accumulating in the alveoli play a major pathogenic role by their regulatory function or through their effects on the inflammatory reaction; controlling the outcome to healing, chronicity or fibrosis. Studies on lymphocytes obtained by bronchoalveolar lavage enable different parameters to be determined whose semiological value is discussed from information acquired in in vitro models of lymphocyte activation. These models show the need for activating signals acting in a sequential manner on cells whose function and mode of response are extraordinarily diversified. Three successive phases may be defined at the time of activation: first a membrane stage consisting of changes in the lipids (metabolism of arachidonic acid) and the cytoskeleton of the cell, a second stage corresponding to the start of the "blastic transformation" with the production of lymphokines with an increase in protein and RNA content (phase G1), then a third stage of DNA synthesis (phase S-G 2) preceding cell division; it is needed for the expression of new markers of differentiation. Nowadays the joint study of the phases of the cell cycle and the expression of antigenic differentiation, identified by monoclonal antibodies within a heterogeneous population, benefit from techniques of flow cytometry. These methods, combined with a measure of mediator production (interleukines) or of non-specific markers of activation liberated by T or B lymphocytes or by macrophages ought to succeed in defining the evolutionary stages or the immune-clinical types of alveolitis. Finally these methods allow the development of cellular immunopharmacology which should lead to new treatments.

Antigens↗
PubMed1983

Improvement of cadaveric renal allograft survival by thoracic duct drainage: relation with T-lymphocyte subset modifications assessed by flow-cytometry.

Thoracic duct drainage (TDD) with reinfusion of cell-free lymph was performed in 118 prospective recipients within four months before transplantation. TDD was unsuccessful in 27 patients (A); it yielded 1-19 X 10(9) lymphocytes in 25 cases (B) and 20-185 X -10(9) in 66 cases (C). The incidence of acute rejection episodes and the requirement for early post-transplant dialysis were lower in C than in A. Six patients were studied for T-lymphocyte subsets, using monoclonal antibodies from OKT series and a monomorphic and HLA-DR (BL2) raised in our laboratory. During TDD peripheral blood lymphocyte (PBL) counts decreased and the percentage of BL2 cells increased. Simultaneously, typical small PBL were replaced by large less differentiated cells slightly labelled by OKT3, some of them bearing both OKT4 and OKT8 markers. The larger the depletion, the earlier the emergence of immature T-cells. In lymph fluid, lymphocyte counts decreased later than in blood, the proportion of T8+ cells lacking Fc receptors increased with time. Changes in B patients were less than in C. These results support the hypothesis that T-cell subset modifications represent the main immunological change accounting for better allograft prognosis.

Antibodies, Monoclonal↗
PubMed1983

Sex steroid receptors in peripheral T cells: absence of androgen receptors and restriction of estrogen receptors to OKT8-positive cells.

The immune response has been reported to be modulated by sex hormones in several models, and estrogen receptors have been demonstrated in the human thymus. We therefore investigated the presence of estrogen and androgen receptors among human peripheral T cells; thoracic duct lymph provided large amounts of circulating lymphocytes. Pure T cells were obtained by negative selection by using complement-dependent cytotoxicity with a monoclonal antibody against a monomorphic determinant of class II histocompatibility antigen (HLA-DR). Furthermore, subsets of OKT8-positive and OKT8-negative lymphocytes were selected by using an OKT8-like monoclonal antibody. Sex steroid binding was determined on purified nuclei; no androgen receptors could be demonstrated on peripheral T cells. The cytoplasmic [3H] 17-beta-estradiol-receptor complex was always translocated to the nucleus in vitro within 1 hr at 37 degrees C; no estrogen receptors were demonstrable on purified OKT4-positive subsets. Assuming that estrogen receptors were evenly distributed among OKT8-positive cells, their level could be estimated to be about 40 fmol/mg DNA. The restriction of estrogen receptors to T cells bearing the "suppressor-cytotoxic" phenotype suggests a possible pathway for the modulation of T cell suppressive activities by estrogens.

Adult↗
PubMed1983

[Lymphomatoid granulomatosis and hypersensitivity pneumopathy. Clinical and biological study (serum and alveolar) toward a new pathogenic hypothesis of the disease].

The authors discussed the malign form of lymphomatoid granulomatosis on the basis of two cases and consider the possible role of an aerocontaminant which is usually responsible for the extrinsic allergic type of alveolitis. A detailed biochemical and cytological study of the alveolar fluid from one of these patients is presented in parallel with immunofluorescent histology and electron microscopy of the lung. The observed biochemical abnormalities in the alveolar fluid could be superimposed on those formed in certain types of hypertensive lung disease. On the other hand the cytology was different, the cytofluorimetric technique revealed a mononuclear cell population rich in RNA whose role in the genesis of the disease of malign nature are discussed. The hypothesis of a hypersecretion of IgA by this malign process is raised by immunofluorescent studies of the lung. The role of IgA in lymphomatoid granulomatosis and bird fanciers lung is discussed in the light of recent work on pigeon IgA.

Adult↗
PubMed1982

Flow cytometry analysis of T lymphocytes in sarcoidosis.

To examine the immunologic alterations in patients with sarcoidosis we characterized the cell cycle phase of T lymphocytes that were collected from peripheral blood and from bronchoalveolar lavage fluid. T-cell DNA and RNA contents were measured at the single cell level using flow cytometry after staining with the metachromatic fluorochrome acridine orange. T-enriched lymphocyte suspensions were obtained from peripheral blood and from bronchoalveolar lavage in 17 patients with histologically-proved sarcoidosis (10 patients, stage I and 7 patients, stage II) and in 4 patients with acute extrinsic hypersensitivity pneumonitis (AEHP). The percentages of cells in the S + (GS + M) phase in the peripheral blood of the patients with sarcoidosis did not differ from those of healthy control subjects. With bronchoalveolar lavage, however, elevated numbers of T cells in the S + (G2 + M) phase were found in the patients with AEHP and in those with stage II sarcoidosis when compared to patients with stage I sarcoidosis. The cellular RNA content of T lymphocytes from the peripheral blood showed a typical bimodal distribution without difference between patients and control subjects. Conversely, T lymphocytes obtained by bronchoalveolar lavage from patients with AEHP and sarcoidosis had a homogeneous low RNA content which differed from that of T lymphocytes from the blood from that of in vitro phytohemagglutinin-stimulated lymphocytes. These findings provide a new approach to the study of the mechanisms of local T-cell activation in sarcoidosis.

Adult↗
PubMed1982

Presence of estrogen binding sites and growth-stimulating effect of estradiol in the human myelogenous cell line HL60.

In the present study, we investigated the effects of estrogens on the growth of the HL60 line in vitro and the presence of estrogen binding sites in the same cells. Cell proliferation was estimated by cell counts, [3H]thymidine incorporation, and determination of the percentage of cells in the S phase by flow cytometry. Cells maintained in a medium containing physiological concentrations of estradiol (10(-9) M, 10(-8) M, 10(-7) M) exhibited a growth stimulation, shown by an increase in the percentage of cells in the S phase, whereas a pharmacological concentration (10(-6) M) produced a growth inhibition. Furthermore, the addition of the specific antihormone, tamoxifen, inhibited the stimulating effect of the estrogens. Receptor analysis showed the presence of specific estrogen-binding sites with an apparent dissociation constant of about 5.3 X 10(-10) M. The effect of estrogen was therefore associated with the presence of estrogen receptors in the human leukemic cell line HL60.

Cell Division↗
PubMed1980

Inhibition of neutrophil-mediated cytotoxicity by alpha 2 macroglobulin.

Highly purified human alpha 2 macroglobulin (1.2--10 mg/ml) was shown to inhibit phytohemagglutinin-induced or antibody-induced lysis of chicken erythrocytes by polymorphonuclear neutrophils. Inhibition was not associated with impaired contact between effector and target cells but rather with the antiprotease activity of alpha 2 macroglobulin.

Animals↗
PubMed1980

[Human lymphocyte receptors for the Fc ends of IgG].

Receptors for Fc IgG can be demonstrated by the binding of aggregated IgG or erythrocyte-IgG antibody complexes (EAG) onto subsets of B, T and "nul" lymphocytes. Among such cells are the effectors of antibody-dependent cell-mediated cytoxicity, and suppressor T cells. The binding of insoluble complexes induces a reversible modulation of the receptors associated with impaired proliferative T cell responses and transient inhibition of IgM receptors expression by adjacent T cells. Soluble receptors for Fc IgG bear a membrane binding site; they inhibit in vitro B cell differentiation induced by-T-dependent or T-independent polyclonal B cell activators.

Antigen-Antibody Complex↗