Original Encounter with Antigen Determines Antigen-Presenting Cell Imprinting of the Quality of the Immune Response in Mice

BACKGROUND:Obtaining a certain multi-functionality of cellular immunity for the control of infectious diseases is a burning question in immunology and in vaccine design. Early events, including antigen shuttling to secondary lymphoid organs and recruitment of innate immune cells for adaptive immune response, determine host responsiveness to antigens. However, the sequence of these events and their impact on the quality of the immune response remain to be elucidated. Here, we chose to study Modified Vaccinia virus Ankara (MVA) which is now replacing live Smallpox vaccines and is proposed as an attenuated vector for vaccination strategies against infectious diseases. METHODOLOGY/PRINCIPAL FINDINGS:We analyzed in vivo mechanisms triggered following intradermal (i.d.) and intramuscular (i.m.) Modified Vaccinia virus Ankara (MVA) administration. We demonstrated significant differences in the antigen shuttling to lymphoid organs by macrophages (MPhis), myeloid dendritic cells (DCs), and neutrophils (PMNs). MVA i.d. administration resulted in better antigen distribution and more sustained antigen-presenting cells (APCs) recruitment into draining lymph nodes than with i.m. administration. These APCs, which comprise both DCs and MPhis, were differentially involved in T cell priming and shaped remarkably the quality of cytokine-producing virus-specific T cells according to the entry route of MVA. CONCLUSIONS/SIGNIFICANCE:This study improves our understanding of the mechanisms of antigen delivery and their consequences on the quality of immune responses and provides new insights for vaccine development

Étude de l’adhésion fibre/matrice d’un matériau composite expansé lors du moussage

Dans une optique d’allégement des structures, les polymères et matériaux composites à matrice organique expansés font leur apparition dans l’industrie. Cependant, leur optimisation est plus complexe que celle de leurs homologues denses, car il faut obtenir une adéquation entre les réactions de polymérisation du polymère et de moussage de l’agent gonflant. De plus, une bonne adhésion fibre/matrice est nécessaire pour obtenir des structures homogènes en termes de répartition et de diamètre de porosités. Une mauvaise adhésion des fibres peut être responsable d’une nucléation hétérogène du polymère, avec l’apparition de grosses porosités, responsables d’une diminution des propriétés mécaniques du matériau

Modification of the mycobacteriophage Ms6 attP core allows the integration of multiple vectors into different tRNA(ala )T-loops in slow- and fast-growing mycobacteria

BACKGROUND: Mycobacteriophage Ms6 integrates into Mycobacterium smegmatis and M. bovis BCG chromosome at the 3' end of tRNA(ala )genes. Homologous recombination occurs between the phage attP core and the attB site located in the T-loop. Integration-proficient vectors derived from Ms6 are useful genetic tools, but their insertion sites in the BCG chromosome remain poorly defined. The primary objective of this study was to identify Ms6 target genes in M. smegmatis and BCG. We then aimed to modify the attP site in Ms6-derived vectors, to switch integration to other tRNA(ala )loci. This provided the basis for the development of recombinant M. bovis BCG strains expressing several reporter genes inserted into different tRNA(ala )genes. RESULTS: The three tRNA(ala )genes are highly conserved in M. smegmatis and BCG. However, in the T-loop of tRNA(alaU )and tRNA(alaV )containing the attB site, a single base difference was observed between the two species. We observed that the tRNA(alaU )gene was the only site into which Ms6-derived integration-proficient vectors integrated in M. smegmatis, whereas in BCG, the tRNA(alaV )gene was used as the target. No integration occurred in the BCG tRNA(alaU )T-loop, despite a difference of only one base from the 26-base Ms6 attP core. We mutated the attP core to give a perfect match with the other tRNA(ala )T-loops from M. smegmatis and BCG. Modification of the seven-base T-loop decreased integration efficiency, identifying this site as a possible site of strand exchange. Finally, two Ms6 vectors were constructed to integrate two reporter genes into the tRNA(alaU )and tRNA(alaV )T-loops of the same BCG chromosome. CONCLUSION: Small changes in the 7 bp T-loop attP site of Ms6 made it possible to use another attB site, albeit with a lower integration efficiency. These molecular studies on BCG tRNA(ala )genes made it possible to create valuable tools for the site-directed insertion of several genes in the same BCG strain. These tools will be useful for the development of novel multivalent vaccines and genetic studies

Bioinformatic analysis of ESTs collected by Sanger and pyrosequencing methods for a keystone forest tree species: oak

<p>Abstract</p> <p>Background</p> <p>The Fagaceae family comprises about 1,000 woody species worldwide. About half belong to the <it>Quercus </it>family. These oaks are often a source of raw material for biomass wood and fiber. Pedunculate and sessile oaks, are among the most important deciduous forest tree species in Europe. Despite their ecological and economical importance, very few genomic resources have yet been generated for these species. Here, we describe the development of an EST catalogue that will support ecosystem genomics studies, where geneticists, ecophysiologists, molecular biologists and ecologists join their efforts for understanding, monitoring and predicting functional genetic diversity.</p> <p>Results</p> <p>We generated 145,827 sequence reads from 20 cDNA libraries using the Sanger method. Unexploitable chromatograms and quality checking lead us to eliminate 19,941 sequences. Finally a total of 125,925 ESTs were retained from 111,361 cDNA clones. Pyrosequencing was also conducted for 14 libraries, generating 1,948,579 reads, from which 370,566 sequences (19.0%) were eliminated, resulting in 1,578,192 sequences. Following clustering and assembly using TGICL pipeline, 1,704,117 EST sequences collapsed into 69,154 tentative contigs and 153,517 singletons, providing 222,671 non-redundant sequences (including alternative transcripts). We also assembled the sequences using MIRA and PartiGene software and compared the three unigene sets. Gene ontology annotation was then assigned to 29,303 unigene elements. Blast search against the SWISS-PROT database revealed putative homologs for 32,810 (14.7%) unigene elements, but more extensive search with Pfam, Refseq_protein, Refseq_RNA and eight gene indices revealed homology for 67.4% of them. The EST catalogue was examined for putative homologs of candidate genes involved in bud phenology, cuticle formation, phenylpropanoids biosynthesis and cell wall formation. Our results suggest a good coverage of genes involved in these traits. Comparative orthologous sequences (COS) with other plant gene models were identified and allow to unravel the oak paleo-history. Simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) were searched, resulting in 52,834 SSRs and 36,411 SNPs. All of these are available through the Oak Contig Browser <url>http://genotoul-contigbrowser.toulouse.inra.fr:9092/Quercus_robur/index.html</url>.</p> <p>Conclusions</p> <p>This genomic resource provides a unique tool to discover genes of interest, study the oak transcriptome, and develop new markers to investigate functional diversity in natural populations.</p

High-quality SNPs from genic regions highlight introgression patterns among European white oaks (Quercus petraea and Q. robur)

International audienceIn the post-genomics era, non-model species like most Fagaceae still lack operational diversity resources for population genomics studies. Sequence data were produced from over 800 gene fragments covering ~530 kb across the genic partition of European oaks, in a discovery panel of 25 individuals from western and central Europe (11 Quercus petraea, 13 Q. robur, one Q. ilex as an outgroup). Regions targeted represented broad functional categories potentially involved in species ecological preferences, and a random set of genes. Using a high-quality dedicated pipeline, we provide a detailed characterization of these genic regions, which included over 14500 polymorphisms, with ~12500 SNPs −218 being triallelic-, over 1500 insertion-deletions, and ~200 novel di- and tri-nucleotide SSR loci. This catalog also provides various summary statistics within and among species, gene ontology information, and standard formats to assist loci choice for genotyping projects. The distribution of nucleotide diversity (θπ) and differentiation (FST) across genic regions are also described for the first time in those species, with a mean n θπ close to ~0.0049 in Q. petraea and to ~0.0045 in Q. robur across random regions, and a mean FST ~0.13 across SNPs. The magnitude of diversity across genes is within the range estimated for long-term perennial outcrossers, and can be considered relatively high in the plant kingdom, with an estimate across the genome of 41 to 51 million SNPs expected in both species. Individuals with typical species morphology were more easily assigned to their corresponding genetic cluster for Q. robur than for Q. petraea, revealing higher or more recent introgression in Q. petraea and a stronger species integration in Q. robur in this particular discovery panel. We also observed robust patterns of a slightly but significantly higher diversity in Q. petraea, across a random gene set and in the abiotic stress functional category, and a heterogeneous landscape of both diversity and differentiation. To explain these patterns, we discuss an alternative and non-exclusive hypothesis of stronger selective constraints in Q. robur, the most pioneering species in oak forest stand dynamics, additionally to the recognized and documented introgression history in both species despite their strong reproductive barriers. The quality of the data provided here and their representativity in terms of species genomic diversity make them useful for possible applications in medium-scale landscape and molecular ecology projects. Moreover, they can serve as reference resources for validation purposes in larger-scale resequencing projects. This type of project is preferentially recommended in oaks in contrast to SNP array development, given the large nucleotide variation and the low levels of linkage disequilibrium revealed

False memory at short and long term.

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Attentional refreshing moderates the word frequency effect in immediate and delayed recall tasks

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A Mouse Model of Celiac Disease

The design and use of mouse models that reproduce key features of human diseases are critical to advance our understanding of the pathogenesis of autoimmune diseases and to test new therapeutic strategies. Celiac disease is a unique organ-specific autoimmune-like disorder occurring in genetically susceptible individuals carrying HLA-DQ2 or HLA-DQ8 molecules who consume gluten. The key histological characteristic of the disease in humans is the destruction of the lining of the small intestine, a feature that has been difficult to reproduce in immunocompetent animal models. This unit describes the DQ8-Dd-villin-IL-15 transgenic mouse model of CeD, which was engineered based on the knowledge acquired from studying CeD patients’ intestinal samples, and which represents the first animal model that develops villous atrophy in an HLA- and gluten-dependent manner without administration of any adjuvant. We provide detailed protocols for inducing and monitoring intestinal tissue damage, evaluating the cytotoxic properties of intraepithelial lymphocytes that mediate enterocyte lysis, and assessing the activation of the enzyme transglutaminase 2, which contributes to the generation of highly immunogenic gluten peptides. Detailed protocols to prepare pepsin-trypsin digested gliadin (PT-gliadin) or chymotrypsin-digested gliadin (CT-gliadin), which allow antibody detection against native or deamidated gluten peptides, are also provided in this unit. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Induction of celiac-like disease in DQ8-Dd-villin-IL-15tg mice Basic Protocol 2: Histological assessment of villous atrophy Support Protocol 1: Morphometric assessment of villous/crypt ratio Support Protocol 2: Evaluation of epithelial cells renewal Support Protocol 3: Evaluation of the density of intraepithelial lymphocytes Basic Protocol 3: Analysis of cytotoxic intraepithelial lymphocytes Basic Protocol 4: Transglutaminase 2 activation and measurement of antibodies against native and deamidated gluten peptides Support Protocol 4: Preparation of CT-gliadin Support Protocol 5: Preparation of PT-gliadin</p

Children's Gist-based False Memory in Working Memory Tasks

International audienceFalse memories are well established episodic memory phenomena. Recent research in young adults has shown that semantically related associates can be falsely remembered as studied items in working memory (WM) tasks for lists of only a few items when a short 4second interval was given between study and test. The present study reported two experiments yielding similar effects in 4-(n = 32 and 33, 18 and 14 females, respectively) and 8-year-old children (n = 33 and 34, respectively, 19 females in both). Short lists of semantically related items specifically tailored for young children were retained over a brief interval. Whether or not the interval was filled with a concurrent task that impeded or not WM maintenance, younger children were as prone to falsely recognize related distractors as their older counterparts in an immediate recognition test, and also in a delayed test. In addition, using the conjoint recognition model of the fuzzy-trace theory, we demonstrated that the retrieval of gist traces of the list themes was responsible for the occurrence of short-term false memories in 4-and 8-year-old children. Gist memory also underpinned the occurrence of false recognition in the delayed test. These findings suggest that young children are as likely to make gist-based false memories as older children in working memory tasks