Genetic Immunisation with Bovine β-Lactoglobulin cDNA Induces a Preventive and Persistent Inhibition of Specific Anti-BLG IgE Response in Mice

International audienceVarious studies have shown that DNA immunisation with gene allergen induces a non-allergic response. We applied this new type of vaccination to bovine β-lactoglobulin (BLG), a major cow’s milk allergen, using a plasmid that allows the production of a partially secreted protein. Specific antibodies and cytokines were quantified in different immunisation protocols. The primary response in mice immunised with BLG-encoding plasmid (pBLG) is of the Th1 type. Restricted recognition of a native form of BLG in pBLG mice contrasted with a broader range of recognition in BLG-in-alum-immunised mice, notwithstanding the fact that alum favours the presentation of a native form of the antigen. We also demonstrated an inhibitory effect of pDNA immunisation on the Th2 response induced by a subsequent immunisation using BLG adsorbed on alum. However, this preventive effect is highly dependent on the time of pre-administration of the pBLG, with an optimal effect when pDNA immunisation occurred at least 21 days before protein administration. This preventive effect resulted concomitantly in the inhibition of BLG-specific IgE, in the induction of specific IgG2a, and in the decrease of the specific IgG1/IgG2 ratio. It is accompanied by an increase in IFNγ and IL-10 secretion. Moreover, the preventive effect was shown to be persistent even after a booster immunisation with alum-adsorbed BLG. The Th1 orientation of the response is very likely due to the presentation of the protein in the Th1 environment due to plasmid immunostimulatory sequences, as intramuscular injection of BLG itself leads to a weak Th2 response and had no preventive effect on a subsequent sensitisation. This study further demonstrates the potential use of DNA immunisation for prevention of IgE response, but the window of action seems to be very restricted if we are to inhibit an established Th2 response efficiently

Recherche de zones fracturees de faible extension par la mise en oeuvre d'un profil sismique vertical et l'application de l'analyse spectrale a entropie maximale

Available from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Etude multi-échelle du potentiel indicateur des biofilms phototrophes en zones agricoles: du bassin versant au micro-habitat

National audienc

Multi-scale study of the potential of phototrophic biofilm as functional indicators in agricultural areas: from catchment basin to micro-habitat

International audienc

Catalyst-free synthesis of alkylpolyglycosides induced by high-frequency ultrasound

International audienc

Toxicity of Environmental and Polystyrene Plastic Particles on the Bivalve Corbicula Fluminea: Focus on the Molecular Responses

International audienceMicroplastics (MPs) and nanoplastics (NPs) are major ecotoxicological concerns in aquatic environments. Among aquatic organisms, filter feeders are particularly exposed to the ingestion of MPs and NPs, filtering large quantities of water for food and having an unselective feeding strategy. The present study investigates the effect of environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized plastic debris collected in the Garonne River (France), and polystyrene NPs (PS NPs) on the freshwater bivalve Corbicula fluminea (Müller 1774). The organisms were exposed to each type of plastic particle at three concentrations: 0.008, 10 and 100 μg L−1 for 21 days. Gene expression measurements were conducted in gills and visceral mass at 7 and 21 days to assess the effects of plastic particles on different functions (endocytosis, detoxication, respiratory chain, oxidative stress, immunity, apoptosis and neurotoxicity). Our results revealed that: i) an up-regulation of genes, mainly involved in endocytosis, oxidative stress, immunity, apoptosis and neurotoxicity, was observed at 7 days of exposure for almost all environmental plastic particles and at 21 days of exposure for PS NPs in the gills, ii) PS NPs at the three concentrations tested and ENV MPs at 0.008 μg L−1 induced strong down-regulation of genes involved in detoxication, oxidative stress, immunity, apoptosis and neurotoxicity at 7 days of exposure in the visceral mass whereas ENV MPs at 10 and 100 μg L−1 and all ENV NPs induced less pronounced effects, iii) overall, PS NPs and ENV MPs 0.008 μg L−1 did not trigger the same effects as ENV MPs 10 and 100 μg L−1 and all ENV NPs, either in the gills or the visceral mass at 7 and 21 days of exposure. This study highlighted the need to use MPs and NPs sampled in the environment for future ecotoxicological studies, compared to manufactured PS NPs as their properties (composition, size distribution, surface charge, additive and adsorbed contaminants) induce different effects at the molecular level to living organisms