Clinical development of placental malaria vaccines and immunoassays harmonization:a workshop report

International audiencePlacental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently in Phase Ia/b clinical trials. During two workshops hosted by the European Vaccine Initiative, one in Paris in April 2014 and the other in Brussels in November 2014, the main actors in placental malaria vaccine research discussed the harmonization of clinical development plans and of the immunoassays with a goal to define standards that will allow comparative assessment of different placental malaria vaccine candidates. The recommendations of these workshops should guide researchers and clinicians in the further development of placental malaria vaccines

Body size as a proxy of probing time and visitation rates on cucumber by two African stingless bees increase fruit quality and seed quantity

Pollinators are of essential importance for sustainable agriculture. However, pollination efficiency depends on interacting factors such as pollinator behaviour and morphology. We compared the effect of probing time length and visit frequency of two distinct body size African stingless bee species (Meliponula bocandei, Dactylurina schmidti) as alternative pollinators to Apis mellifera scutellata on greenhouse cultivated cucumber. We found differences in morphometric characteristics, between a set of 9 body parameters. Bee body size was the morphological feature that varied the most among bee species. On average, body size was largest in honeybees, followed by M. bocandei, and finally D. schmidti, which was the smallest. Glossa length was different between the bee species: A. mellifera scutellata (2.86 ± 0.026 mm), M. bocandei (2.20 ± 0.031 mm), D. schmidti (0.72 ± 0.025 mm). Such differences among bee species in body parameters correspondingly affected nectar probing times during a single flower visit, which were different for the bee species. D. schmidti (3.34 ± 0.56 s) had the longest probing time, while M. bocandei (2.57 s) had the shortest. Fruit quality was strongly positively influenced by the visit duration during a single visit on female flowers. The slope of fruit quality produced was higher in flowers pollinated by M. bocandei. During a single flower visit, heavier and bigger fruits were obtained in the gold standard hand cross pollination and flowers pollinated by M. bocandei. The bee species and the number of visits significantly impacted fruit weight, fruit volume and number of seeds. Subsequent visit performed by M. bocandei positively impacted fruit quality. Three visits on a flower were enough to ensure the production of high-quality fruits. Fruit sweetness depended on the number of visits received by the flower, but not on the bee species that performed the visit. Altogether, our results indicate that the stingless bees M. bocandei is more an efficient pollinator of cucumber than A. m. scutellata and D. schmidti and can be recommended for use under greenhouse cultivation

Can the shape of the wing help in the identification of African stingless bee species? (Hymenoptera: Apidae: Meliponini)

info:eu-repo/semantics/publishe

Down-selection of the VAR2CSA DBL1-2 expressed in E. coli as a lead antigen for placental malaria vaccine development

International audienceOver 50 million women are exposed to the risk of malaria during pregnancy every year. Malaria during pregnancy is a leading global cause of maternal morbidity and adverse pregnancy outcomes. Adhesion of Plasmodium falciparum-infected erythrocytes to placental chondroitin-4-sulfate (CSA) has been linked to the severe disease outcome of placental malaria. Accumulated evidence strongly supports VAR2CSA as the leading placental malaria vaccine candidate. Recombinant proteins encompassing the VAR2CSA high affinity CSA binding site have been generated, and their activity as immunogens that elicit functional (inhibitory) and crossreactive antibodies against CSA-binding parasites assessed. The expression of His-tagged proteins was compared in four different expression systems and their capacity to bind specifically to CSA was analyzed. CHO cells and E. coli SHuffle cells were the two expression systems able to express some of the recombinant proteins in reasonable amounts. Larger analytical scale production of DBL1x-2× (3D7) and DBL3x-4ε (FCR3) best expressed in CHO and E. coli SHuffle cells were performed. Purified proteins were administered to rats either alone or adjuvanted with human approved adjuvants. Analysis of the functionality and cross-reactivity of the induced antibodies allowed us to down-select the DBL1x-2(3D7) expressed in E. coli SHuffle cells as the best antigen to be transitioned to further clinical development in order to protect future pregnant women living in malaria endemic areas against the severe clinical outcomes of placental malaria