title: Arrested B lymphopoiesis and persistence of activated B cells in adult interleukin 7(-/)- mice.
abstract: Interleukin 7 is a crucial factor for the development of murine T and B lymphocytes. We now report that, in the absence of interleukin 7, B lymphocyte production takes place exclusively during fetal and perinatal life, ceasing after 7 wk of age. In peripheral organs, however, the pool of B lymphocytes is stable throughout adult life and consists only of cells that belong to the B1 and marginal zone (MZ) compartments. This is accompanied by a 50-fold increase in the frequency of immunoglobulin (Ig)M- and IgG-secreting cells, and the concentration of serum immunoglobulins is increased three- to fivefold. Both the MZ phenotype and the increase in serum IgM are T cell independent. These findings reveal a previously undescribed pathway of B lymphopoiesis that is active in early life and is interleukin 7 independent. This pathway generates B1 cells and a normal sized MZ B lymphocyte compartment.
authors.affiliation: Instituto Gulbenkian de Ciência, 2781 Oeiras, Portugal.
authors.forename: T L
authors.initials: TL
authors.lastname: Carvalho
authors.forename: T
authors.initials: T
authors.lastname: Mota-Santos
authors.forename: A
authors.initials: A
authors.lastname: Cumano
authors.forename: J
authors.initials: J
authors.lastname: Demengeot
authors.forename: P
authors.initials: P
authors.lastname: Vieira
mesh_terms: D000375:Aging / Q000097:blood; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D015415:Biomarkers; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation; D005260:Female; D006410:Hematopoiesis; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D016130:Immunophenotyping; D015851:Interleukin-7 / Q000235:genetics / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D010950:Plasma Cells / Q000166:cytology / Q000276:immunology; D013154:Spleen / Q000166:cytology
chemical_list: D015415:Biomarkers; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015851:Interleukin-7