Project description:Developing B lymphocytes undergo V(D)J recombination to assemble germline V, D, and J gene segments into exons that encode the antigen-binding variable region of immunoglobulin (Ig) heavy (H) and light (L) chains. IgH and IgL chains associate to form the B cell receptor (BCR), which upon antigen binding activates B cells to secrete BCR as an antibody. Each of the huge number of clonally independent B cells expresses a unique set of IgH and IgL variable regions. Ability of V(D)J recombination to generate vast primary B cell repertoires results from combinatorial assortment of large numbers of different V, D, and J segments, coupled with diversification of the junctions between them to generate the complementary determining region 3 (CDR3) for antigen contact. Approaches to evaluate in depth the content of primary antibody repertoires and, ultimately, to study how they are further molded by secondary mutation and affinity maturation processes are of great importance to the B cell development, vaccine, and antibody fields. We now describe an unbiased, sensitive, and readily accessible assay, referred to as HTGTS repertoire sequencing (HTGTS-Rep-seq), to quantify antibody repertoires. HTGTS-Rep-seq quantitatively identifies the vast majority of IgH and IgL V(D)J exons, including their unique CDR3 sequences, from progenitor and mature mouse B lineage cells via the use of specific J primers. HTGTS-Rep-seq also accurately quantifies DJH intermediates and V(D)J exons in either productive or non-productive configurations. HTGTS-Rep-seq should be useful for studies of human samples, including clonal B-cell expansions and also for following antibody affinity maturation processes. We employed high-throughput genome-wide translocation sequencing adapted repertoire sequencing (HTGTS-Rep-seq) to study antibody repertoires. For HTGTS-Rep-seq libraries, we utilize bait coding ends of J segments to identify, in unbiased fashion, mouse IgH DJH repertoires [processed tlx files] along with both productive and non-productive IgH V(D)J repertoires from both pro-B and peripheral B cells [processed xls files of samples 1-18, 21-51]. Similarly, we also identify mouse productive and non-productive Igk repertoires from peripheral B cells [processed xls files of samples 19,20,52-57].
Project description:Recent advancements in microfluidics and high-throughput sequencing technologies have enabled recovery of paired heavy- and light- chain of immunoglobulins (Ig) and VDJ- and VJ- chains of T cell receptors (TCR) from thousands of single cells simultaneously. Due to the complexity of these polyclonal receptors, for many species single-cell immune repertoire sequencing assays are not yet commercially available. Rhesus macaques are one of the most well-studied model organisms of the human adaptive immune response; application of these new immune repertoire sequencing assays is highly relevant to vaccine and infectious disease studies. Here we use custom designed primers to target and enrich for every known Ig and TCR chain and isotype in the rhesus macaque animal model. We sequenced more than 110,000 cell barcodes from rhesus macaque repertoires using PBMC, splenocyte, and FACS-sorted T and B cell. We were able to recover every Ig and TCR isotype, measure clonal expansion in proliferating T cells, and pair repertoires with gene expression profiles of single cells. Our results establish the ability to perform single-cell based immune repertoire analysis in rhesus macaque.
Project description:B cells are known to have different properties and BCR repertoires depending on the time of development. Our objective is to investigate the BCR repertoire of B cells across embryonic, neonatal, and adult stages, particularly in cells with a RAG2 expression history. We focus on sequencing and analyzing the immunoglobulin heavy chain (IGH) genes of these cells to understand their BCR diversity and specificity. Additionally, we explore the relationship between B-1a cells and bone marrow IgM+ plasmablasts/plasma cells, aiming to shed light on the development and function of B-1a cells in the immune system.
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:In response to antigen challenge, human B cells clonally expand, undergo selection and differentiate within secondary lymphoid tissues to produce mature B cell subsets and high affinity antibodies necessary for an effective immune response. However, the interplay between affinity, antibody class and different B cell fates has proved challenging to decipher in primary human tissue. We have applied an integrated analysis of bulk and single-cell antibody repertoires paired with single-cell transcriptomics of human B cells from a model secondary lymphoid tissue. Specifically, here we have performed bulk B cell repertoire sequencing of the immunoglobulin heavy chain (IgH) for sorted B cell subsets from paediatric tonsil tissue. Matched single-cell gene expression and single-cell VDJ data are also available for the same patient donors.
Project description:The transcription factor FOXP1 is implicated in the pathogenesis of B-cell lymphomas through immunoglobulin heavy chain (IGH) locus-related chromosomal translocations leading to dysregulated expression of FOXP1. Translocations of FOXP1 with non-IG gene sequences have been also reported, but the molecular consequences of such aberrations remain undetermined. Here, using molecular cytogenetics and molecular biology studies, we comprehensively analyzed four lymphoma cases with non-IG rearrangements of FOXP1 and compared these with cases harboring t(3;14)(p13;q32)/IGH-FOXP1 and FOXP1-expressing lymphomas without underlying t(3p13/FOXP1). We found that non-IG rearrangements are usually acquired during evolution of lymphoma and constantly target the coding region of FOXP1, promiscuously fusing with coding and non-coding gene sequences at various reciprocal breakpoints (2q36, 10q24 and 3q11). Intriguingly, these rearrangements do not generate functional chimeric genes but commonly disrupt the full-length FOXP1 transcript leading to an aberrant expression of N-truncated FOXP1 isoforms, as shown by QRT-PCR and Western blot analysis. In contrast, cases with t(3;14)(p13;q32)/IGH-FOXP1 overexpress the full-length FOXP1. Collectively, our findings point to a dual mechanism through which FOXP1 is implicated in B-cell lymphomagenesis. The primary t(3;14)(p13;q32)/IGH-FOXP1 produces the full-length protein with potent oncogenic activity, whereas the secondary non-IG 17 rearrangements of FOXP1 generate N-truncated FOXP1 isoforms, likely driving progression of disease. Using molecular cytogenetics and molecular biology studies (including RNA-seq), we comprehensively analyzed four lymphoma cases with non-IG rearrangements of FOXP1 and compared these with cases harboring t(3;14)(p13;q32)/IGH-FOXP1 and FOXP1-expressing lymphomas without underlying t(3p13/FOXP1).
Project description:Background: V(D)J recombination is an essential process for the generation of diverse antigen receptor (AgR) repertoires. In B cells, immunoglobulin kappa (Igk) light chain locus recombination follows recombination of the immunoglobulin heavy chain (Igh) locus. We recently developed the DNA-based VDJ-seq assay for the unbiased quantitation of Igh VH and DH repertoires. In conjunction with genome-wide datasets for several epigenetic features, we showed that two active chromatin states, located at the recombination signal sequences (RSS) of VH genes, are highly predictive of recombination. The contribution of chromatin features to Vk gene choice in recombination remains poorly understood. Results: We adapted the VDJ-seq assay to profile the Igk VkJk repertoire, and obtained a comprehensive readout of highly variable Vk gene usage in mouse bone marrow pre-B cells. We identified PU.1 binding at the RSS as highly predictive of whether a gene will actively recombine or not. Prediction of the frequency of recombination was more dependent on H3K4 methylation and IKAROS binding. Conclusions: Epigenetic features within the Vk region are able to explain much of the variation in Vk gene usage. Whilst PU.1 binding at the RSS appears to play a binary, all-or-nothing role, priming Vk genes for recombination, the frequency with which these genes recombine is shaped by the presence and enrichment of a number of other epigenetic features. In contrast to the Igh locus, the epigenetic landscape of the promoter as well as the RSS is predictive of Vk gene recombination.
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:IgCaller is a python program designed to fully characterize the immunoglobulin (IG) gene rearrangements and oncogenic translocations in lymphoid neoplasms from whole-genome sequencing (WGS) data. Using a cohort of 331 patients comprising different subtypes of B-cell neoplasms, we demonstrate that IgCaller identifies both heavy and light chain rearrangements providing additional information on their functionality, somatic mutational status, class switch recombination, and oncogenic IG translocations. We provided here IG reads of the previously unpublished WGS.