title: Origin of thymic and peritoneal Ly-1 B cells.
abstract: Murine Ly-1 B cells were first found in the peritoneal cavity (Per C). It has been thought that Ly-1 B cells are responsible for the development of autoimmune diseases, since they spontaneously produce autoantibodies. However, we have found that such Ly-1 B cells are present in the thymus of normal mice, and that they play a crucial role in negative selection in the Mls system. In addition, thymic Ly-1 B cells and Per C Ly-1 B cells have been found to differ in function, ontogeny and location. In this communication, we report on the different origins of these cells. C57BL/6 mice are lethally irradiated and reconstituted with fetal (day 14) liver cells or bone marrow cells from 4-, 6- or 12-week-old mice. Fetal liver cells are shown to have the capacity to reconstitute both thymic and Per CLy-1 B cells, whereas bone marrow cells from 6- or 12-week-old mice have the capacity to reconstitute thymic Ly-1 B cells, but not Per C Ly-1 B cells, indicating that fetal hemopoietic stem cells (HSC) differ from HSC in the bone marrow of adult mice, and that thymic and Per C Ly-1B cells have different origins.
authors.affiliation: First Department of Pathology, Kansai Medical University, Osaka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Than
authors.forename: M
authors.initials: M
authors.lastname: Inaba
authors.forename: K
authors.initials: K
authors.lastname: Inaba
authors.forename: Y
authors.initials: Y
authors.lastname: Fukuba
authors.forename: Y
authors.initials: Y
authors.lastname: Adachi
authors.forename: S
authors.initials: S
authors.lastname: Ikehara
mesh_terms: D000367:Age Factors; D000818:Animals; D000950:Antigens, Ly / Q000032:analysis*; D001402:B-Lymphocytes / Q000502:physiology*; D001854:Bone Marrow Cells; D005333:Fetus / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D010529:Peritoneal Cavity / Q000166:cytology*; D013154:Spleen / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D000950:Antigens, Ly