Project description:Lyme disease (Borrelia burgdorferi infection) is increasingly recognized as a significant source of morbidity world-wide. Here, we investigated B cell responses to Lyme disease through molecular identifier-enabled antibody heavy chain sequencing of bulk B cells from PBMCs. Single-cell immunoglobulin sequencing of paired heavy- and light-chain genes from this project will also be separately deposited. Additional information regarding patient characteristics and overlap with other data from the SLICE study is available upon request.
Project description:Chip-chip from pro-B cells from Rag1KO mice for H3K27ac and RNA Pol II Identification of novel enhancers from Ig heavy and light chain loci Rag1KO pro-B epigenetic landscape at Ig heavy and light chain loci
Project description:Chip-chip from pro-B cells from Rag1KO mice for H3K27ac and RNA Pol II Identification of novel enhancers from Ig heavy and light chain loci
Project description:Lyme disease (Borrelia burgdorferi infection) is increasingly recognized as a significant source of morbidity world-wide. Here, we investigated B cell responses to Lyme disease through barcode-enabled single cell sequencing of activated B cells (plasmablasts) sorted from PBMCs. Bulk immunglobulin heavy-chain sequencing from this project has also been separately deposited. Additional information regarding patient characteristics and overlap with other data from the SLICE study is available upon request.
Project description:Cell lines were generated by transfecting NS0 myeloma cells with a single vector which contained the genes for the heavy and light chain of the antibody anti-CD38, and also the selectable marker glutamine synthetase. After two rounds of limiting dilution cloning, long-term continuous culture was performed on two cell lines (4H8 and 4G3) to assess the stability of recombinant antibody production during periods of extended culture. Microarray analysis was performed on RNA samples extracted during log phase of growth at the start of long-term culture and after approximately one month.
Project description:B cells reactive toward phosphatidylcholine (PtC) are enriched in the B1 B cell subset, and express predominantly one of two VH/Vk combinations to confer this specificity: VH12/Vk4/5H and VH11/Vk9. Studies of transgenic mice expressing the VH12 heavy chain (VH12 mice) suggest two major checkpoints for light chain expression in this system: the first involves selection of V-J rearrangements which encode a “permissive” light chain that can functionally pair with the VH12 heavy chain; the second involves receptor editing to salvage non-PtC reactive B cells to acquire a permissive light chain that confers PtC reactivity. If this model is correct, impairing receptor editing should reduce the frequency of PtC-reactive B1 B cells in VH12 mice. To test this possibility, we bred VH12 mice to transgenic mice expressing a catalytically inactive form of RAG1 (dnRAG1 mice) which show a defect in receptor editing. Interestingly, dnRAG1 expression in VH12 mice enforces development of PtC-reactive B1 B cells, rescuing the loss of splenic B cells observed in VH12 mice. These data suggest receptor editing normally functions to remove a large portion of PtC-specific B cells in VH12 mice. Deep sequencing of the expressed light chain repertoire of PtC-reactive and non-reactive B cells in VH12 mice revealed that PtC-reactive B cells predominantly expressed the Vk4/5H (IGKV4-91) light chain gene, whereas PtC-non-reactive B cells expressed a broader, yet restricted, set of light chain genes. This analysis also revealed a low frequency of in-frame hybrid light chain genes appearing to originate via Type 2 gene replacement, which we show can originate from template switching during PCR.
Project description:Existing methods for paired antibody heavy- and light-chain repertoire sequencing rely on specialized equipment and are limited by their commercial availability and high costs. Here, we report a novel simple and cost-effective emulsion-based single-cell paired antibody repertoire sequencing method that employs only basic laboratory equipment. We performed a proof-of-concept using mixed mouse hybridoma cells and we also showed that our method can be used for discovery of novel antigen-specific monoclonal antibodies by sequencing human CD19+ B cell IgM and IgG repertoires isolated from peripheral whole blood before and seven days after Td (Tetanus toxoid/Diphtheria toxoid) booster immunization. We anticipate broad applicability of our method for providing insights into adaptive immune responses associated with various diseases, vaccinations, and cancer immunotherapies.
Project description:Productive rearrangement of the immunoglobulin heavy chain locus triggers a major developmental checkpoint that promotes limited clonal expansion of pre-B cells, culminating in cell cycle arrest and rearrangement of the kappa (κ) or lambda (λ) light-chain loci. B lineage cells lacking the related transcription factors IRF-4 and IRF-8 undergo a developmental arrest at the cycling pre-B cell stage and are blocked for light-chain recombination. Using Irf-4,8-/- pre-B cells we demonstrate that two pathways converge to synergistically drive light-chain rearrangement, a process that is not simply activated by cell cycle exit. One pathway is directly dependent on IRF-4, whose expression is elevated by pre-BCR signaling. IRF-4 targets the κ 3′ and λ enhancers to increase locus accessibility and positions a kappa allele away from pericentromeric heterochromatin. The other pathway is triggered by attenuation of IL-7 signaling and results in activation of the κ intronic enhancer via binding of the transcription factor, E2A. Intriguingly, IRF-4 regulates the expression of CXCR4 and promotes the migration of pre-B cells in response to the chemokine CXCL12. We propose that IRF-4 coordinates the two pathways regulating light-chain recombination by positioning pre-B cells away from IL-7 expressing stromal cells. We used microarrys to identify the changes in gene expression under different levels of the cytokine IL-7 and after rescue of genetic defect. Keywords: growth conditions and rescue