Project description:T-Box Expressed in T cells (TBET) and CD11c expression in B cells is linked with IgG2c isotype switching, virus-specific immune responses, and humoral autoimmunity. However, the activation requisites and regulatory cues governing TBET and CD11c expression remain poorly defined. In this article, we reveal a relationship among TLR engagement, IL-4, IL-21, and IFN-g that regulates TBET expression in B cells. We find that IL-21 or IFN-g directly promote TBET+ expression in the context of TLR engagement. Further, IL-4 antagonizes TBET induction. Finally, IL-21, but not IFN-g, promotes CD11c expression independent of TBET. Using influenza virus and Heligmosomoides polygyrus infections, we show that these interactions function in vivo to determine whether TBET+ and CD11c+ B cells are formed. These findings suggest that TBET+ B cells seen in health and disease share the common initiating features of TLR-driven activation within this circumscribed cytokine milieu.
Project description:Activated naïve (aNAV) B cells have been shown to be the precursor of the CD11c+T-bet+ IgD−CD27− double negative (DN)2 or atypical memory (aMEM) B cells in systemic lupus erythematosus (SLE). To determine factors that maintain resting naïve (rNAV) B cells, the transcriptomics program in naïve (IGHD+IGHM+) B cells in human healthy controls (HC) and SLE was analyzed by single cell RNA-sequencing analysis. In HC, naive B cells expressed IL-4 pathway genes whereas in SLE, naive B cells expressed type I interferon stimulated genes (ISGs). In HC, aNAV B cells exhibited upregulation of gene signature of germinal center (GC) and classical memory (cMEM) B cells. In contrast, in SLE, aNAV B cells expressed signature genes of aMEM. In vitro exposure of SLE B cells to IL-4 promoted B cell development into CD27+CD38+ plasmablasts/plasma and IgD−CD27+ cMEM B cells. The same treatment blocked the development of CD11c+Tbet+ aNAV and DN2 B cells and preserved DN B cells as CD11c−Tbet− DN1 B cells. Lower expression of IL-4R and increased intracellular IFN-β in naïve B cells was correlated with the accumulation of CD21−IgD− B cells and the development of anti-Smith and anti-DNA autoantibodies in SLE patients (n=47). Our results show that IL-4R and type I IFN signaling in naïve B cells induce the development of distinct lineages of cMEM versus aMEM B cells, respectively. Further, a diminished IL-4R signaling shifted activated B-cell development from the DN1 to the DN2 trajectory in SLE patients. Therapies that enhance IL-4R signaling may be beneficial for ISGhi SLE.
Project description:Lactobacilli are probiotics that, among other health promoting effects, have been ascribed immunostimulating and virus preventive properties. Certain lactobacilli species have been shown to possess strong IL-12 inducing properties. As IL-12 production depends on the up-regulation of type I interferons, we hypothesized that the strong IL-12 inducing capacity of L. acidophilus NCFM in murine bone marrow derived DC is caused by an up-regulation of IFN-β, which subsequently stimulates the induction of IL-12 and the dsRNA binding toll like receptor (TLR)-3. The expression of the genes encoding IFN-β, IL-12, IL-10 and TLR-3 in DC upon stimulation with L. acidophilus NCFM was measured. L. acidophilus NCFM induced a much stronger expression of ifn-β, il-12 and il-10 compared to the synthetic dsRNA ligand Poly I:C, whereas the levels of expressed tlr-3 were similar. By the use of whole genome microarray gene expression, we investigated whether other genes related to the viral defence were up-regulated in DC upon stimulation with L. acidophilus NCFM and found that various virus defence related genes, both early and late, were among the strongest up-regulated genes. The IFN-β stimulating capability was also detected in another L. acidophilus strain, but was not a property of other probiotic bacteria tested (B. bifidum and E. coli nissle).The IFN-β inducing capacity was markedly reduced in TLR-2 -/- DCs, dependent on endocytosis and the major cause of the induction of il-12 and tlr-3 in L. acidophilus NCFM stimulated cells. Collectively, our results reveal that certain lactobacilli trigger the expression of viral defence genes in DC in a TLR-2 manner through induction of IFN- β. Experiment Overall Design: In the experiment Lactobacillus NCFM were added to murine dendritic cells and stimulated for 4, 10 or 18 hours. These were compared to control experiment at the same timepoints. Experiments were run in triplicates except for control 10h and control 18h which were only in duplicate, giving a total of 16 arrays.
Project description:In recent years, a circulating subset of B cells phenotypically negative for CD21 has been reported to be expanded in chronic infectious and autoimmune inflammatory diseases. While reports on the function of these cells differ by disease origin, their role in rheumatoid arthritis (RA) has remained elusive. Here, we combine clinical data with flow cytometric analyses for patients untreated for and newly diagnosed with RA. We show correlations between the frequency of CD21-Tbet+CD11c+ and destruction of both cartilage and bone in in the joints of patients at the time of diagnosis. Combining single-cell 5’ RNA sequencing with B-cell receptor (VDJ)-enriched sequencing, we are able to identify the Tbet+CD11c+ cells in the scRNA-seq data from untreated newly diagnosed RA patients. Further, we describe a characteristic gene expression pattern, with overrepresentation of upregulated genes involved in antigen processing and presenting processes. The same gene signature is near identically expressed by autoimmune-associated cells infiltrating synovial tissue of RA patients. Our findings suggest that Tbet+CD11c+ B cells may be poised for antigen presentation in the periphery, and could be capable of recirculating between the periphery and joint tissue, thereby promoting autoimmune responses. Overall, we demonstrate a potential pathogenic role of Tbet+CD11c+ B cells in RA, in which they contribute to joint destruction.
Project description:Lactobacilli are probiotics that, among other health promoting effects, have been ascribed immunostimulating and virus preventive properties. Certain lactobacilli species have been shown to possess strong IL-12 inducing properties. As IL-12 production depends on the up-regulation of type I interferons, we hypothesized that the strong IL-12 inducing capacity of L. acidophilus NCFM in murine bone marrow derived DC is caused by an up-regulation of IFN-β, which subsequently stimulates the induction of IL-12 and the dsRNA binding toll like receptor (TLR)-3. The expression of the genes encoding IFN-β, IL-12, IL-10 and TLR-3 in DC upon stimulation with L. acidophilus NCFM was measured. L. acidophilus NCFM induced a much stronger expression of ifn-β, il-12 and il-10 compared to the synthetic dsRNA ligand Poly I:C, whereas the levels of expressed tlr-3 were similar. By the use of whole genome microarray gene expression, we investigated whether other genes related to the viral defence were up-regulated in DC upon stimulation with L. acidophilus NCFM and found that various virus defence related genes, both early and late, were among the strongest up-regulated genes. The IFN-β stimulating capability was also detected in another L. acidophilus strain, but was not a property of other probiotic bacteria tested (B. bifidum and E. coli nissle).The IFN-β inducing capacity was markedly reduced in TLR-2 -/- DCs, dependent on endocytosis and the major cause of the induction of il-12 and tlr-3 in L. acidophilus NCFM stimulated cells. Collectively, our results reveal that certain lactobacilli trigger the expression of viral defence genes in DC in a TLR-2 manner through induction of IFN- β.
Project description:Inflammatory (B220+ CD19+ CD44+ CD11c+ Tbet-AmCyanhi) B cells were sorted from female Tbet-AmCyan reporter mice at day 8, 10, and 15 post infection with LCMV-Armstrong. RNA-seq was employed to assess transcriptional changes in inflammatory B cells throughout the infection.
Project description:Inflammatory (B220+ CD19+ CD44+ CD11c+ Tbet-AmCyanhi) B cells were sorted from female Tbet-AmCyan reporter mice at day 8, 10, and 15 post infection with LCMV-Armstrong. RNA-seq was employed to assess transcriptional changes in inflammatory B cells throughout the infection.
Project description:Inflammatory (B220+ CD19+ CD44+ CD11c+ Tbet-AmCyanhi), GC (B220+ IgDlo CD95+ GL-7+), and naive follicular B cells (B220+ CD19+ IgDhi CD23+) were sorted from male Tbet-AmCyan reporter mice at day 12 post infection with LCMV-Armstrong. RNA-seq was employed to compare the transcriptomes of these three B cell populations.
Project description:IFN-γ has been reported to be the ABC-promoting cytokine combined with signaling from IL-21, CD40L, Ag-BCR and TLR7 agonist. Hence, we adopted the in vitro differentiation cocktails (anti-IgM, R848, anti-CD40, IL-21 plus IFN-γ or IL-4) to determine the role of IFN-γ in ABC differentiation. Mouse splenic B cells were purified by negative selection and cultured in the presence of the above cocktails. Compared with IL-4, IFN-γ-polarized cells preferentially differentiated to ABC-like cells. And RNA-seq were performed on IFN-γ-polarized cells and IL-4-polarized cells.
Project description:Following combined stimulation through Toll-like receptor (TLR)-9 and the B-cell receptor (BCR), human B cells were sorted based on IL-10 expression. Microarray analysis showed that just ~0.7% of genes were differentially expressed between IL-10- and IL-10+ B-cells. However, connectivity map analysis revelaed that the IL-10+ cells were those undergoing differentiation to germincal centre B cells, and we identified a CD11c- B-cell subset that was enriched in cells capable of producing IL-10