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An organ culture technique was used to investigate the migration and the morphological evolution of lymphocytes from lymphopoietic tissues. This evolution was compared with the behavior of cells extracted from the tissue and kept ...
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An organ culture technique was used to investigate the migration and the morphological evolution of lymphocytes from lymphopoietic tissues. This evolution was compared with the behavior of cells extracted from the tissue and kept in nutritive medium in vitro. It was found that cells were continuously migrating from the fragments of lymph nodes or spleen, and were attaching to the glass. They spread on glass, their protoplasm enlarged and their nucleus became clearer. The evolution towards blastoid cells was identical with that described under artificial stimulation by PHA for example. Cytological identification of the cells actively engaged in antibody synthesis (as detected by local hemolysis in gum) at the time of staining, showed that several distinct cellular types were active, including plasma cells and macrophagelike cells. It is assumed that the stimulated lymphocytes, after spontaneous migration from the tissue are able to evolve into an "immunoblast" stage and then, eventually after fixation upon a physical support, to initiate antibody synthesis.
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摘要 :
By combining a tissue culture method with the detection of antibody-producing cells by local hemolysis in gum it has been possible to follow the immunological activity of cells from tissue fragments for long period of time.These f...
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By combining a tissue culture method with the detection of antibody-producing cells by local hemolysis in gum it has been possible to follow the immunological activity of cells from tissue fragments for long period of time.These fragments were obtained from lymph nodes or spleens of rabbits immunized by sheep erythrocytes.It was found that, while the immunological activity of the free cells in suspensions decreased fast and disappeared in a few days, the cells attaching on glass could express their activity for at least 3 wk. It is assumed that these cells are the daughters of cells from the fragments which were not active antibody producers at the beginning, but differentiated, during the culture, into cells endowed with two capacities: glass adherence and antibody synthesis.One can further admit that the type of culture employed exerts a selective pressure favoring formation of antibody-producing cells.
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à l’heure actuelle, les virus grippaux à l’origine des cas de grippe humaine saisonnière circulant à l’échelle mondiale appartiennent à deux sous-types A, les sous-types A(H1N1) et A(H3N2), et à deux lignages de virus de...
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à l’heure actuelle, les virus grippaux à l’origine des cas de grippe humaine saisonnière circulant à l’échelle mondiale appartiennent à deux sous-types A, les sous-types A(H1N1) et A(H3N2), et à deux lignages de virus de type B, les lignages B/Yamagata et B/Victoria.Comme celles dues aux virus de type A, les grippes dues aux virus de type B sont susceptibles d’avoir de sévères conséquences qui justifient sa prévention.Jusqu’à présent, en France, les vaccins utilisés pour prévenir la grippe saisonnière étaient trivalents ciblant systématiquement des virus appartenant aux deux sous-types A et à l’un ou l’autre des lignages B.L’efficacité protectrice des vaccins trivalents est diminuée les saisons où des virus appartenant aux deux lignages B cocirculent ou encore lorsque la souche de virus de type B circulante dominante appartient à un lignage différent de celui de la souche vaccinale.En ciblant des virus appartenant aux deux lignages B, les vaccins quadrivalents améliorent la concordance antigénique entre les souches de type B circulantes et vaccinales.Trois vaccins grippaux quadrivalents inactivés ont une autorisation de mise sur le marché en France et devraient être disponibles pour la saison 2018–2019.Il est attendu qu’en offrant une protection plus large, les vaccins grippaux quadrivalents améliorent l’efficacité vaccinale, la confiance dans la vaccination du grand public, la satisfaction des professionnels de santé et qu’ils participent finalement à compléter la couverture vaccinale contre la grippe.
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The isolation of influenza virus 80 years ago in 1933 very quickly led to the development of the first generation of live-attenuated vaccines. The first inactivated influenza vaccine was monovalent (influenza A). In 1942, a bivale...
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The isolation of influenza virus 80 years ago in 1933 very quickly led to the development of the first generation of live-attenuated vaccines. The first inactivated influenza vaccine was monovalent (influenza A). In 1942, a bivalent vaccine was produced after the discovery of influenza B. It was later discovered that influenza viruses mutated leading to antigenic changes. Since 1973, the WHO has issued annual recommendations for the composition of the influenza vaccine based on results from surveillance systems that identify currently circulating strains. In 1978, the first trivalent vaccine included two influenza A strains and one influenza B strain. Currently, there are two influenza B lineages circulating; in the latest WHO recommendations, it is suggested that a second B strain could be added to give a quadrivalent vaccine. The history of influenza vaccine and the associated technology shows how the vaccine has evolved to match the evolution of influenza viruses.
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Après la première vague de la pandémie grippale A H1N1 2009, les 23es Rencontres du GEIG, qui se sont déroulées les 25 et 26 novembre 2010 à Paris, ont permis de présenter les différents retours d'expériences sur cette pa...
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Après la première vague de la pandémie grippale A H1N1 2009, les 23es Rencontres du GEIG, qui se sont déroulées les 25 et 26 novembre 2010 à Paris, ont permis de présenter les différents retours d'expériences sur cette pandémie. Parmi les 193 pays membres de l'Organisation mondiale de la santé (OMS), 100 n'avaient pas ou peu de surveillance virologique de la pandémie. En dépit de cette hétérogénéité des réseaux de surveillance de circulation des virus grippaux suivant les pays, levirus pandémique A H1N1 2009 a diffusé en moins de neuf semaines à tous les continents selon l'OMS. Lors de la précédente pandémie A H3N2 en 1968, la diffusion à l'échelle de la planète avait été observée en 15 semaines.
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