BCR repertoire of B cells with distinct developmental timings

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. Overall design: We generated a novel RAG2-based doxycycline-inducible/repressible temporal lymphoid-lineage labeling system, which avoids the potentially toxic effects of tamoxifen on embryos and enables noninvasive labeling to track B cells developed at embryonic, neonatal, and adult periods under native hematopoietic conditions. Utilizing this system in combination with LC1 and Rosa-tdTomato mice, we sorted and analyzed BCR repertoire sequences in B cells developed at these distinct developmental stages.