Project description:We performed single-cell RNA-sequencing to create a cell census of the human thymus during development, early childhood and adult life. We sampled 15 embryonic and fetal thymi spanning thymic developmental stages between 7 post-conception weeks (PCW) to 17 PCW, and 9 postnatal thymi from paediatric and adult samples. We compared the cellular composition and T cell differentiation within human and mouse thymus using newly generated and repository mouse datasets. Finally, we investigated the bias in the recombination and selection of human versus mouse TCR repertoires.
Project description:We report that a large percentage of thymic B cells undergo class switching intrathymically. Thymic B cell class switching requires cognate T-B interaction. To determine whether B cell specificity was also important for thymic B cell class-switching, we sorted class-switched thymic B cells (CD19+B220+IgM-IgD-), unswitched B cells (CD19+B220+IgM+IgD+) and bulk splenic B cells in 3H9 heavy chain-fixed mice and performed high throughput sequencing analysis of the light chain of these populations. Results of this analysis indicated that class-switched thymic B cells have a distinct repertoire compared with unswitched thymic B cells and splenic B cells. Further reactivity tests indicated that a large part of BCRs enriched in class-switched thymic B cells are autoreactive. These data suggest that autoreactive B cells are selected into class-switched population and expanded in the thymus. Light chain repertoire profiles of class-switched thymic B cells, unswithced thymic B cells and splenic B cells from 3H9 mice were generated by deep sequencing.
Project description:We report that a large percentage of thymic B cells undergo class switching intrathymically. Thymic B cell class switching requires cognate T-B interaction. To determine whether B cell specificity was also important for thymic B cell class-switching, we sorted class-switched thymic B cells (CD19+B220+IgM-IgD-), unswitched B cells (CD19+B220+IgM+IgD+) and bulk splenic B cells in 3H9 heavy chain-fixed mice and performed high throughput sequencing analysis of the light chain of these populations. Results of this analysis indicated that class-switched thymic B cells have a distinct repertoire compared with unswitched thymic B cells and splenic B cells. Further reactivity tests indicated that a large part of BCRs enriched in class-switched thymic B cells are autoreactive. These data suggest that autoreactive B cells are selected into class-switched population and expanded in the thymus.
Project description:To characterize thymic APCs in an unbiased manner, we generated a scRNA-seq atlas of thymic antigen presenting cells (APCs) isolated from thymic rosettes, cellular complexes of physically interacting thymocytes and APCs. Around 8,000 APCs were captured, mostly haematopoietic in origin, consisting of B cell, dendritic cell and macrophage lineages.
Project description:To illustrate the immune cell atlas and functional heterogeneity of T cell repertoire in murine heart transplantation,we established the murine heterotopic heart transplantation model and isolated CD45 positive cells from cardiac grafts and spleens for single cell transcriptome and TCR sequencing.