title: p53 regulates Btk-dependent B cell proliferation but not differentiation.
abstract: Btk is critical for B cell development and proliferation. Mice lacking Btk have a defect in B cell development, resulting in a loss of mature B cells and decreased proliferative responses following B cell receptor cross-linking. In contrast, mice deficient in the tumor suppressor p53 display increases in developing B cell populations in the bone marrow. To investigate the potential role of p53 in Btk-dependent B cell development and function, we generated mice doubly-deficient in p53 and Btk. Btk/p53-deficient mice showed an increase in splenic B220+ cell numbers compared with Btk-deficient mice, although there was no recovery in B cell subset differentiation. In contrast to the lack of recovery of B cell development, there was a recovery in lipopolysaccharide and anti-immunoglobulin M (IgM) plus interleukin-4-induced proliferation of Btk/p53-deficient B cells, although there was no recovery to anti-IgM stimulation alone. Thus, p53 promotes B cell expansion and proliferation, but p53 deficiency cannot compensate for Btk deficiency in the development of B cell subsets.
authors.affiliation: Department of Pediatrics and Microbiology and Immunology and Walther Oncology Center, Indiana University School of Medicine, and Walther Cancer Institute, RI 2600, Indianapolis, IN 46202, USA.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Schmidt
authors.forename: Lindsey D
authors.initials: LD
authors.lastname: Mayo
authors.forename: David B
authors.initials: DB
authors.lastname: Donner
authors.forename: Mark H
authors.initials: MH
authors.lastname: Kaplan
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D001854:Bone Marrow Cells / Q000166:cytology; D002452:Cell Count; D002454:Cell Differentiation / Q000276:immunology*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000276:immunology; D007159:Immunologic Tests; D051379:Mice; D018345:Mice, Knockout; D008934:Mitogens / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*
chemical_list: D008934:Mitogens; D016159:Tumor Suppressor Protein p53; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase