Project description:XCR1+ dendritic cells (DC) have been shown to excel in antigen cross-presentation for the activation of naÃ¯ve CD8 T cells. This property was reported to be associated to the subset of the XCR1+ DC expressing IL-12b upon ex vivo stimulation for 24 h with a mixture of CpG, IFN-Î³, and GM-CSF (Lin ML et al. Proc Natl Acad Sci USA. 2008. PMID: 18272486). DC found in the steady-state non-lymphoid tissues undergo an homeostatic, tolerogenic, maturation and migrate to the draining lymph nodes to interact with naive autoreactive T cells and induction their peripheral tolerance. In contrast, spleen DC are thought to exist solely in an immature state. The aim of this study was to re-examine heterogeneity within steady state spleen XCR1+ DC, in particular examining whether this population encompass a fraction of mature DCs as assessed through their expression of CCR7 and/or the Il12b gene. Indeed, we show that a small fraction of XCR1+ spleen DC constitutively mature into two distinct but likely successive activation stages characterized as CCR7+ and CCR7+Il12b+ respectively, and correlated with increasing ability to cross-present antigen to naÃ¯ve CD8 T cells. Transcriptomic analysis of the subsets of XCR1+ DC found in steady state spleen unexpectedly showed that their homeostatic maturation was unexpectedly associated with up-regulated of many genes thought to drive pro-inflammatory T-cell responses and previously found to be commonly induced upon maturation of distinct DC subsets in response to stimulation by various microbial-type stimuli (Vu Manh TP et al. Eur J Immunol. 2013. PMID: 23553052). Thus, our results reveal that spleen XCR1+ DC undergo constitutive maturation and emphasize the common mechanisms operating upon homeostatic, tolerogenic, DC maturation versus microbial-type stimuli-induced, immunogenic, DC maturation. DC were isolated from the spleen of untreated Il12b-EYFP reporter mice (Reinhardt RL et al. J Immunol. 2006. PMID:16849470) mice as previously described (Robbins SH et al. Genome Biol. 2008. PMID: 18218067; Baranek T et al. Cell Host Microbe. 2012. PMID: 23084923). DC subsets were sorted by flow cytometry according to the marker combinations described in the âcharacteristics: phenotypeâ field for each sample.

Project description:Background : Poxviruses have been shown to be efficient vectors for the production of protective immune responses in host species but also in on host species. Myxoma virus belongs to poxviridae family. In order to evaluate the capacity of (MYXV) as a vaccine vector in ruminants, we invistigated its interactions with bone marrow-derived dendritic cells (BM-DC). DCs are the most potent antigen-presenting cells and play a crucial role during the priming and reactivation of antigen-specific immune responses . Following infection by a pathogen, the functional changes of DC are essential since priming and polarization of the immune response depend on these changes . Therefore a better understanding of the modifications in gene expression of proinflammatory cytokines, chemokines and stimulatory molecules expression may prove useful in predicting whether or not a vaccine vector will be effective. Moreover, it may help identifying modifications for improving its efficacy. Methodology/Principal Findings: We investigated in vitro the interactions between recombinant MYXV expressing GFP protein, SG33-GFP and ovine BM-DCs. To gain a global view of the gene remodelling induced by MYXV, we infected BM-DCs from three sheep with SG33-GFP at different multiplicity of infection (MOI) (0, 1, 3) during different time (0, 3, 8 hours). We measured the expression of 15K probes in BM-DCs after each kind of conditions with ovine Agilent microarrays. Furthermore, a selected number of genes were confirmed by RT-qPCR. MYXV infection induces a strong reprogramming of the cells leading to the expression of pro-inflammatory cytokines and mobilisation of type I IFN pathways, cellular death and features associated with the activation of the adaptive immune response. Conclusion/Significance: Microarray profiling of a poxvirus-DC interaction help to delineate some interesting features of a vector candidate in ovine, and pave the way for additional improvements of a promising platform. Keywords : Myxoma virus ; bone marrow-derived dendritic cells ; transcriptome ; sheep; vaccine 9 samples: 3 time points and 3 replicates of MOI=1

Project description:Background : Poxviruses have been shown to be efficient vectors for the production of protective immune responses in host species but also in on host species. Myxoma virus belongs to poxviridae family. In order to evaluate the capacity of (MYXV) as a vaccine vector in ruminants, we invistigated its interactions with bone marrow-derived dendritic cells (BM-DC). DCs are the most potent antigen-presenting cells and play a crucial role during the priming and reactivation of antigen-specific immune responses . Following infection by a pathogen, the functional changes of DC are essential since priming and polarization of the immune response depend on these changes . Therefore a better understanding of the modifications in gene expression of proinflammatory cytokines, chemokines and stimulatory molecules expression may prove useful in predicting whether or not a vaccine vector will be effective. Moreover, it may help identifying modifications for improving its efficacy. Methodology/Principal Findings: We investigated in vitro the interactions between recombinant MYXV expressing GFP protein, SG33-GFP and ovine BM-DCs. To gain a global view of the gene remodelling induced by MYXV, we infected BM-DCs from three sheep with SG33-GFP at different multiplicity of infection (MOI) (0, 1, 3) during different time (0, 3, 8 hours). We measured the expression of 15K probes in BM-DCs after each kind of conditions with ovine Agilent microarrays. Furthermore, a selected number of genes were confirmed by RT-qPCR. MYXV infection induces a strong reprogramming of the cells leading to the expression of pro-inflammatory cytokines and mobilisation of type I IFN pathways, cellular death and features associated with the activation of the adaptive immune response. Conclusion/Significance: Microarray profiling of a poxvirus-DC interaction help to delineate some interesting features of a vector candidate in ovine, and pave the way for additional improvements of a promising platform. Keywords : Myxoma virus ; bone marrow-derived dendritic cells ; transcriptome ; sheep; vaccine

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IL-12 From Endogenous cDC1, and Not Vaccine DC, Is Required for Th1 Induction

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