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Biomedical subjects

O Garraud

Publications and source records attributed to O Garraud.

64 records · Page 4Linked to original sources
PubMed1986

[Prognosis of follicular lymphoma in a series of 180 cases].

In this series, the prognosis and the course of 180 cases of follicular lymphomas, classified according to Kiel's classification, seen before any treatment, treated and followed in the same institution were analyzed. In the first part, 6 primary prognostic factors were identified: compression, age of patient, stage, general symptoms, pathological subtype, lymphography. The most significant parameter (p less than 10(-10], obtained secondarily, was complete remission obtained in 63.9% of patients. In the second part, a multivariate analysis permitted to identify a few groups of patients for whom the probability of complete remission varied between 25 and 100%. Knowledge of these prognostic parameters may help to tailor treatment to each case and to obtain the best survival possible.

Adult↗
PubMed1984

Effect of blood storage on lymphocyte subpopulations.

In the evaluation of helper and suppressor T lymphocyte subpopulations testing of the cells may not be carried out until the day following collection of the blood. The possibility that changes occur during overnight storage at 4 degrees C or 22 degrees C has been investigated. No statistical differences in percentages of helper and suppressor T cells between fresh samples and overnight stored samples were found if the blood was kept at 22 degrees C.

Antibodies, Monoclonal↗
PubMedDate not supplied

Peripheral blood mononuclear cells in the squirrel monkey Saimiri sciureus: characterization and functional aspects of T lymphocytes.

Characterization and functional aspects of squirrel monkey peripheral blood mononuclear cells (PBMC), and mainly T cells, are described in the present paper; this should enable the study of cellular immune responses in an experimental model for malaria. PBMC were obtained from Ficoll-Hypaque gradient separation and fractionated into T cells and non-T cells by means of E-rosetting techniques and adherence to plastic dishes. PBMC subset phenotypes were characterized by means of monoclonal antibodies (mAb) directed against human leukocyte differentiation antigens (Ag), fluoresceinated lectins, anti-surface Ig (squirrel-monkey-specific) antibodies (Ab) and latex bead ingestion assays. PBMC functions were assayed through lymphoblastic transformation tests (LTT) in the presence of either numerous mitogenic, comitogenic and anti-mitogenic lectins or anti-human leukocyte differentiation Ag mAb. We sought to standardize reference values for lymphocyte phenotypes and functions in normal squirrel monkeys (prior to experimental infection). We also present evidence that splenectomy (generally rendered necessary for experimental human malaria infection) performed six months prior to the present investigation did not modify PBMC numbers and functions in the tested animals.

Animals↗
PubMedDate not supplied

Peripheral blood mononuclear cells in the squirrel monkey Saimiri sciureus. II. Exploration of the IL2/IL2R pathway of T-cell activation.

We report here on functional aspects of squirrel monkey T cells isolated either from peripheral blood mononuclear cells or in the presence of accessory cells or accessory-cell-secreted cytokines. The T-cell response triggered by polyclonal activators was measured through proliferation, T-cell growth factor production and transient expression of receptors to growth factors. We also sought to delineate mechanisms by which antimitogenic molecules might prevent lymphocytes from being able to express "activation antigens" and/or from proliferating. Under these conditions, we mainly explored the inducible IL2/IL2R pathway and phenomena occurring in lymphocyte "non-activation" in terms of early and late cellular events; indeed, defects in the IL2/IL2R pathway represent one of the dysregulation events presumed to occur during the acute phase of human malaria, disease for which. Saimiri monkeys have been selected as experimental hosts.

Animals↗
PubMedDate not supplied

Squirrel monkey (Saimiri sciureus) B lymphocytes: secretion of IgG directed to Plasmodium falciparum antigens, by primed blood B lymphocytes restimulated in vitro with parasitized red blood cells.

Blood B lymphocytes obtained from Plasmodium falciparum-immune Saimiri monkeys were assayed for their in vitro differentiation in immunoglobulin-secreting cells upon restimulation with P. falciparum-parasitized Saimiri red blood cells. Selected culture conditions enabled appropriately stimulated blood B cells to secrete 3F11/G10+ IgG, detected in the supernatants by means of a dot immunobinding assay. Primed blood B lymphocytes from P. falciparum-immune Saimiri monkeys were thus able to secrete IgG when restimulated by parasitized red blood cells in the presence of T cell- and monocyte-derived cytokines (recombinant human cytokines). These primed blood B cells, which were able to differentiate, were shown to secrete antibodies reactive with P. falciparum-infected red blood cells, as detected by means of an indirect immunofluorescence assay, and reactive with P. falciparum-infected red blood cell extracts, as detected by means of Western blot analysis. Furthermore, due to the possibility of discriminating between IgG subtypes in the squirrel monkey (3F11/G10+::3A2/G6+ IgG [associated with protection against the blood stages of P. falciparum] vs. 3F11/G10+::3E4/H8+ IgG [usually not functionally associated with protection]), we have attempted to estimate the respective proportions of each IgG subtype. In defined culture conditions, Saimiri monkey blood B cells preferentially secrete 3F11/G10+::3E4/H8+ IgG in response to parasitized red blood cells. We therefore discuss the conditions that would render this assay suitable for the selection, among P. falciparum blood stage antigens, of those that have major B-cell epitopes.

Animals↗
PubMedDate not supplied

Schistosomiasis co-infection in humans influences inflammatory markers in uncomplicated Plasmodium falciparum malaria.

Malaria and schistosomiasis are the two major parasite diseases present in developing countries. The epidemiological co-infection with schistosomiasis could influence the development of the physiological reaction associated with Plasmodium falciparum infection in human. Most studies have demonstrated the association of circulating levels of interferon-gamma (IFN-gamma), tumour necrosis factor-a (TNF-alpha), interleukin-10 (IL-10), transforming growth factor (TGF-beta) and soluble Tumour Necrosis Factor Receptors (sTNF-RI and sTNF-RII) with the morbidity of malaria. In the present study, we showed that Schistosoma haematobium co-infection influences, in an age-dependent manner, the unbalance between pro- and anti-inflammatory circulating cytokines that play a key role during malaria infection. Indeed, children co-infected by S. haematobium have higher levels of IFN-gamma and sTNF-RII than children infected only by P. falciparum. In contrast, co-infected adults presented a significant increase of IFN-gamma, IL-10, TGF-beta, sTNF-RI and sTNF-RII rates and IL-10/TNF-alpha ratio. Taken together, this study indicates that schistosomiasis co-infection can unbalance the regulation of inflammatory factors in uncomplicated P. falciparum malaria. The possible consequences of the schistosomiasis co-infection for age-dependent malaria morbidity are discussed.

Adolescent↗
PubMedDate not supplied

Differential downstream effects of CD40 ligation mediated by membrane or soluble CD40L and agonistic Ab: a study on purified human B cells.

With the addition of various cytokines, the CD40-CD40 ligand (CD40L) system can act as a T-helper cell surrogate to permit B lymphocytes to produce large amounts of polyclonal Ig. In the present study, we tested six CD40-CD40L stimulation models: (i, ii) soluble agonistic 89 and G28.5 mAbs ; (iii, iv) 89 and G28.5 bound via their Fc fragments on CDw32-transfected mouse fibroblasts; (v) purified, soluble, trimeric human CD40L molecules (sCD40L); and (vi) human CD40L expressed by a CD40L-transfected mouse fibroblastic cell line (LCD40L). Target B cells consisted of purified blood and tonsillar CD19+ lymphocytes cultured in the presence of CD40 stimuli and IL-2 and IL-10, added at the onset of each B cell culture. A) There was differential expression of CD69, CD80 and CD86 exposure to sCD40L and LCD40L was ensued by the strongest % MFI changes over control. B) In blood B cells, mAbs and sCD40L induced IgA, IgM and IgG production almost equally well; LCD40L proved less efficient. In contrast, in tonsil B cells, LCD40L induced significantly more IgA, IgG1, IgG3 and IgM production than other signals. Using certain CD40/CD40L stimuli to model in vitro Ig production, a system used regularly in many laboratories, may affect the interpretation based on the cell type and on the CD40/CD40L system used.

Animals↗
PubMedDate not supplied

Short report: IgG1/IgG3 antibody responses to various analogs of recombinant ypfmsp119--a study in immune adults living in areas of Plasmodium falciparum transmission.

To further characterize protective-type (IgG1/IgG3) antibody responses to Plasmodium falciparum blood stage in putatively immune individuals' plasma, we have tested for various analogs of the 19 kDa C-terminus of the MSP1 antigen obtained as secreted recombinant proteins from Saccharomyces cerevisiae. One of four proteins was then identified on the basis of consistent IgG3, along with less variable IgG1 recognition. This protein has thus been selected for further functional assays of IgG1/IgG3 antibodies.

Animals↗