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O de Bouteiller

Publications and source records attributed to O de Bouteiller.

28 records · Page 2Linked to original sources
PubMed1995

Memory B cells from human tonsils colonize mucosal epithelium and directly present antigen to T cells by rapid up-regulation of B7-1 and B7-2.

Human memory B cells that carry mutated IgV region genes were isolated from tonsils by negative selection of IgD+ naive B cells and CD38+ germinal center B cells and plasma cells. They were mainly found within the intraepithelial areas, but not in the B cell follicles of human tonsils. Memory B cells but not naive B cells have the capacity to present antigen directly to T cells, owing to the constitutive expression of the accessory molecules B7-1/CD80 and B7-2/CD86. Signals through antigen receptors and CD40 antigen result in these two molecules being further up-regulated more rapidly and strongly on memory B cells than on naive B cells. The unique anatomical localization of memory B cells beneath the surface of mucosa, together with their strong APC capacity, may explain the well-known prompt and robust secondary antibody responses.

Antigen-Presenting Cells↗
PubMed1994

Analysis of somatic mutation in five B cell subsets of human tonsil.

Using a series of phenotypic markers that include immunoglobulin (Ig)D, IgM, IgG, CD23, CD44, Bcl-2, CD38, CD10, CD77, and Ki67, human tonsillar B cells were separated into five fractions representing different stages of B cell differentiation that included sIgD+ (Bm1 and Bm2), germinal center (Bm3 and Bm4), and memory (Bm5) B cells. To establish whether the initiation of somatic mutation correlated with this phenotypic characterization, we performed polymerase chain reaction and subsequent sequence analysis of the Ig heavy chain variable region genes from each of the B cell subsets. We studied the genes from the smallest VH families (VH4, VH5, and VH6) in order to facilitate the mutational analysis. In agreement with previous reports, we found that the somatic mutation machinery is activated only after B cells reach the germinal center and become centroblasts (Bm3). Whereas 47 independently rearranged IgM transcripts from the Bm1 and Bm2 subsets were nearly germline encoded, 57 Bm3-, and Bm4-, and Bm5-derived IgM transcripts had accumulated an average of 5.7 point mutations within the VH gene segment. gamma transcripts corresponding to the same VH gene families were isolated from subsets Bm3, Bm4, and Bm5, and had accumulated an average of 9.5 somatic mutations. We conclude that the molecular events underlying the process of somatic mutation takes place during the transition from IgD+, CD23+ B cells (Bm2) to the IgD-, CD23-, germinal center centroblast (Bm3). Furthermore, the analysis of Ig variable region transcripts from the different subpopulations confirms that the pathway of B cell differentiation from virgin B cell throughout the germinal center up to the memory compartment can be traced with phenotypic markers. The availability of these subpopulations should permit the identification of the functional molecules relevant to each stage of B cell differentiation.

Antigens, CD↗
PubMed1987

Ontogeny of T lymphocyte differentiation in the human fetus: acquisition of phenotype and functions.

Phenotype and functions of cells of the T lymphocyte lineage from fetal liver, thymus, spleen and bone marrow were investigated at various ages. T lymphocyte differentiation was shown to be initiated in the thymus after the 7th week of gestation. In this organ, a large number of cells with a phenotype comparable to that of children thymocytes and with a high proliferative response to phytomitogens was observed at the 14th week. The fetal liver and bone marrow never contained many T-cells and the liver was shown to be virtually devoid of any of these cells before the 13th week. Fetal spleen contained appreciable amounts of T-cells after the 13th week. Helper and suppressor activities of fetal thymocytes and splenocytes were acquired between the 12th and the 16th week, but they were never as complete nor as potent as those of adult lymphocytes. HLA antigens were detected in very low amount in lymphocytes from the various organs at the beginning of the second trimester and their expression was significantly enhanced by in vitro incubation with alpha-interferon (alpha-IFN), a procedure that permits easier HLA typing of fetal cells.

Antibodies, Monoclonal↗
PubMed1984

Trimethylmethoxyphenyl-retinoic acid (Ro 10-1670) and lymphocyte DNA synthesis activity in vitro.

Trimethylmethoxyphenyl-retinoic acid (TMMPRA), the main active therapeutic form of etretinate, was used for in vitro studies on human lymphocytes. Lymphocyte DNA synthesis remained unchanged when TMMPRA was added to the cultures at a concentration range of 1.25-25 micrograms/ml culture medium. No modulatory activity of the drug on DNA synthesis was seen on cultured lymphocytes stimulated by lectins (phytohemagglutinin, pokeweed mitogen, concanavalin A) or by a mitogen selective for a T lymphocyte subpopulation, phorbol myristate acetate. Concanavalin A induced T suppressor cell activity tested toward the proliferative response to allogeneic stimuli was lowered by TMMPRA. The results indicated that TMMPRA alone or in the presence of lectins or phorbol myristate acetate did not inhibit or stimulate DNA synthesis activity in vitro but that the drug could lower T suppressor cell activity.

Acitretin↗