title: Kinetic modeling reveals a common death niche for newly formed and mature B cells.
abstract: BACKGROUND
  B lymphocytes are subject to elimination following strong BCR ligation in the absence of appropriate second signals, and this mechanism mediates substantial cell losses during late differentiation steps in the bone marrow and periphery. Mature B cells may also be eliminated through this mechanism as well as through normal turnover, but the population containing mature cells destined for elimination has not been identified. Herein, we asked whether the transitional 3 (T3) subset, which contains most newly formed cells undergoing anergic death, could also include mature B cells destined for elimination.
  
  
  RESULTS
  To interrogate this hypothesis and its implications, we applied mathematical models to previously generated in vivo labeling data. Our analyses reveal that the death rate of T3 B cells is far higher than the death rates of all other splenic B cell subpopulations. Further, the model, in which the T3 pool includes both newly formed and mature primary B cells destined for apoptotic death, shows that this cell loss may account for nearly all mature B cell turnover.
  
  
  CONCLUSIONS
  This finding has implications for the mechanism of normal mature B cell turnover.
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Gitit
authors.initials: G
authors.lastname: Shahaf
authors.forename: Michael P
authors.initials: MP
authors.lastname: Cancro
authors.forename: Ramit
authors.initials: R
authors.lastname: Mehr
mesh_terms: D000465:Algorithms; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology*; D016923:Cell Death; D002454:Cell Differentiation; D002465:Cell Movement; D003198:Computer Simulation; D007700:Kinetics; D051379:Mice; D008954:Models, Biological; D015233:Models, Statistical; D008962:Models, Theoretical; D010641:Phenotype; D013154:Spleen / Q000473:pathology