Reprise de l'embryogenèse adventive à partir d'embryons somatiques de caféier (Coffea arabica L.) après leur congélation dans l'azote liquide

Des embryons somatiques de caféiers (#C. arabica$ L.), obtenus à partir d'explants foliaires, survivent à une congélation à -196°C. Les jeunes embryons sont isolés puis cultivés pendant 24 heures sur un milieu enrichi en saccharose (0,75 M). Ils sont ensuite mis à incuber pendant 2 heures dans une solution cryoprotectrice contenant la même concentration en saccharose et 5 % de diméthysulfoxyde. Placés dans des ampoules cryobiologiques, ils sont alors congelés lentement, jusqu'à -40°C, avant d'être plongés et conservés dans de l'azote liquide. Après un réchauffement rapide dans un bain-marie à 40°C, les embryons sont repiqués chaque jour sur des milieux dont la concentration en saccharose est progressivement abaissée jusqu'à la valeur standard de 0,1 M. Le taux de reprise de l'embryogenèse adventive atteint 50 %, 17 semaines après le réchauffement. Les premières plantules, obtenues in vitro à partir de matériel congelé, ont un développement apparemment normal. Dans un proche avenir, la technique mise au point pourrait être élargie à d'autres espèces actuellement entretenues en champ par les stations de recherche caféière. (Résumé d'auteur

Superior efficacy of a human immunodeficiency virus vaccine combined with antiretroviral prevention in simian-human immunodeficiency virus-challenged nonhuman primates

International audienc

P19-26. Directing macaque immune responses with an anti-dendritic cell HIV Gag p24 fusion protein vaccine

International audiencen.

Increased percentage of T cells with the expression of CD127 and CD132 in hypertrophic adenoid in children with otitis media with effusion

The hypertrophic adenoid may promote chronic suppurative otitis media in children as it fulfills its immune function. The number of lymphocytes in the adenoid and their cooperation in the immune response depend of on their proliferation and migration to the effector sites. Interleukin 7 (IL-7) is essential for the normal development and function lymphocytes. IL-7 plays pivotal role for activation and proliferation of T and B cells. The heterodimeric interleukin-7 receptor (IL-7R) is composed of the IL-7Rα (127) and the common cytokine receptor γc (CD132). The aim of this study was to evaluate the percentage of lymphocytes T (CD4+ and CD8+) with IL-7R (CD127 and CD132) expression in hypertrophic adenoid in children suffering with otitis media with effusion for a duration of 3 months. Adenoid excised due to hypertrophy with or without chronic otitis media with effusion was used as study material. CD4+ CD127+, CD4+132+, CD8+CD127+ and CD8+CD132+ cell subpopulations were identified using monoclonal antibodies and flow cytometry. The percentage of CD4+ and CD8+ T cells with CD127 receptor expression in hypertrophic adenoid of children with otitis media with effusion was statistically significantly higher than in hypertrophic adenoid group. The percentage of CD4+ T cells with CD132 expression in the study group was statistically significantly higher than in the reference group. The percentage of CD8+ T cells with CD132+ expression was not statistically different in both groups. The increased percentage of T lymphocytes with IL-7R expression (CD127 and CD132) in hypertrophic adenoid seems to influence the quantity of lymphocytes and upset the immunological function of tonsils which can influence the course of otitis media with effusion

Towards an In Vitro Model of Plasmodium Hypnozoites Suitable for Drug Discovery

Contains fulltext : 96475.pdf (publisher's version ) (Open Access)BACKGROUND: Amongst the Plasmodium species in humans, only P. vivax and P. ovale produce latent hepatic stages called hypnozoites, which are responsible for malaria episodes long after a mosquito bite. Relapses contribute to increased morbidity, and complicate malaria elimination programs. A single drug effective against hypnozoites, primaquine, is available, but its deployment is curtailed by its haemolytic potential in glucose-6-phosphate dehydrogenase deficient persons. Novel compounds are thus urgently needed to replace primaquine. Discovery of compounds active against hypnozoites is restricted to the in vivo P. cynomolgi-rhesus monkey model. Slow growing hepatic parasites reminiscent of hypnozoites had been noted in cultured P. vivax-infected hepatoma cells, but similar forms are also observed in vitro by other species including P. falciparum that do not produce hypnozoites. METHODOLOGY: P. falciparum or P. cynomolgi sporozoites were used to infect human or Macaca fascicularis primary hepatocytes, respectively. The susceptibility of the slow and normally growing hepatic forms obtained in vitro to three antimalarial drugs, one active against hepatic forms including hypnozoites and two only against the growing forms, was measured. RESULTS: The non-dividing slow growing P. cynomolgi hepatic forms, observed in vitro in primary hepatocytes from the natural host Macaca fascicularis, can be distinguished from similar forms seen in P. falciparum-infected human primary hepatocytes by the differential action of selected anti-malarial drugs. Whereas atovaquone and pyrimethamine are active on all the dividing hepatic forms observed, the P. cynomolgi slow growing forms are highly resistant to treatment by these drugs, but remain susceptible to primaquine. CONCLUSION: Resistance of the non-dividing P. cynomolgi forms to atovaquone and pyrimethamine, which do not prevent relapses, strongly suggests that these slow growing forms are hypnozoites. This represents a first step towards the development of a practical medium-throughput in vitro screening assay for novel hypnozoiticidal drugs