title: Cutting edge: Primary and secondary effects of CD19 deficiency on cells of the marginal zone.
abstract: Marginal zone (MZ) B cells are absent in CD19(-/-) mice. Possible causes include an intrinsic defect in B cells and/or a secondary defect in the extrinsic MZ microenvironment as a result of changes in B cell differentiation in mice lacking CD19. Cells in the MZ also include MZ macrophages (MZM) and MZ dendritic cells (DC). Although CD19 is only expressed on B cells, SIGN-R1(+) MZM are absent and CD11c(+) MZ DC distribution is abnormal in CD19(-/-) mice. Adoptively transferred B cells from normal mice are able to reconstitute MZ B cells in CD19(-/-) mice. In contrast, CD19(-/-) B cells could not enter the MZ of the normal mice. Furthermore, MZM distribution and MZ DC distribution are restored following MZ B cell reconstitution in CD19(-/-) mice. Thus, MZ B cells are required for MZM differentiation and MZ DC localization, but the deficiency of MZ B cells in CD19(-/-) mice is caused by a defect of intrinsic B cell signaling.
authors.affiliation: Department of Microbiology, University of Alabama at Birmingham, Birmingham AL 35294, USA.
authors.forename: Yuying
authors.initials: Y
authors.lastname: You
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.forename: Robert H
authors.initials: RH
authors.lastname: Carter
mesh_terms: D000818:Animals; D018941:Antigens, CD19 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D015398:Signal Transduction / Q000276:immunology; D013154:Spleen / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
chemical_list: D018941:Antigens, CD19