title: ABCB1 transporter discriminates human resting naive B cells from cycling transitional and memory B cells.
abstract: The exact identification of B cell subsets is instrumental to understand their dynamics under physiological and pathological conditions. Human memory B cells are currently identified according to the expression of CD27, which is absent on naive B cells. We report here that the ATP-binding cassette (ABC)B1 transporter is exclusively present on mature CD27- naive B cells, while it is absent in CD27+ memory B cells and in a heterogeneous subset of CD27- cells that comprise both switch memory and transitional B cells. Thus, ABCB1 activity precisely discriminates naive from transitional and all memory B cells. Using this improved method to discriminate human B cell subsets, and Ki67 staining to identify recently divided cells, we show that in both cord blood and adult peripheral blood, mature naive B cells are quiescent while transitional B cells and memory B cells have a high in vivo turnover.
authors.affiliation: Institute for Research in Biomedicine, Bellinzona, Switzerland. stefan.wirths@irb.unisi.ch
authors.forename: Stefan
authors.initials: S
authors.lastname: Wirths
authors.forename: Antonio
authors.initials: A
authors.lastname: Lanzavecchia
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000097:blood* / Q000502:physiology; D000328:Adult; D016175:B-Lymphocyte Subsets / Q000145:classification / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*; D002453:Cell Cycle / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D006801:Humans; D007156:Immunologic Memory; D007231:Infant, Newborn; D016192:Resting Phase, Cell Cycle / Q000276:immunology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1