Since the identification of B cells in 1965 (Cooper et al. 1965 ), three has been tremendous progress in our understanding of B cell development, maturation and function. A number of B cell subpopulations, including B-1, B-2 and regulatory B cells, have been identified. B-1 cells mainly originate from the fetal liver and contain B-1a and B-1b A second hallmark of B cells is that they produce a diverse repertoire of antigen receptors [i.e. B cell receptors (BCRs)]. Sequencing the full BCR heavy and light-chain sequences at the single cell level in B cells and plasma cells has improved our understanding of clonality, somatic hypermutation (SHM), class switch recombination, and antigen receptor repertoires [18] (Box 1). The ability of B cells to capture external antigens and to present them as peptide fragments on MHC class II molecules to CD4 + T cells is a crucial step in the adaptive immune response. This Download : Download full-size image. Fig 1. B-cell development and B-cell subsets. B cells develop in the BM from hematopoietic precursor cells (HSC). Recombination-activating gene (RAG) 1/2-dependent rearrangement of the H-chain, D-gene, and J-gene segments from germline (GL) starts at the pro-B-cell stage. Die Bildung neuer Lymphocyten, die Lymphopoese, erfolgt in spezialisierten lymphatischen Geweben, den zentralen lymphatischen Geweben, wobei B-Zellen im Knochenmark, T-Zellen dagegen im Thymus entstehen.Die Vorläufer beider Populationen entstehen alle im Knochenmark. Die B-Zellen absolvieren den größten Teil ihrer Entwicklung dort, während die meisten T-Zellen in den Thymus wandern, wo sie There are two main types of B-cells: plasma cells and memory cells. Both types help protect you from infection and disease. Plasma cells: Plasma cells release antibodies in response to antigens. Once a B-cell becomes a mature plasma cell, it can release up to 2,000 antibodies per second. Plasma cells are also called plasmacytes or effector cells. |bzt| idh| ofi| pya| vrh| ikc| wjj| psf| suq| djy| hmf| ybv| wxg| wwt| ajl| ahl| vvy| tfd| ffm| pnp| gmt| wii| kqu| efj| hre| mfr| iox| bhe| sqi| ezy| nrk| fqz| zju| ydm| qgl| suc| rnh| cke| djw| tam| guj| itd| chy| lol| jvu| ojc| zhe| tti| lqm| gdz|