title: Bu-1 antigen expression as a marker for B cell precursors in chicken embryos.
abstract: Genetically polymorphic cell surface antigen, Bu-1, is expressed on B cells as well as on a subset of macrophages. Bu-1+ cells are also present in embryonic spleen and bone marrow, and these could represent prebursal precursors for B cells and Bu-1+ macrophages. To test the repopulation capacity of these cells we sorted 14-day embryonic spleen cells from Bu-1a-homozygous donors into Bu-1a+ and Bu-1a- fractions and transferred them into age-matched irradiated Bu-1b-homozygous recipients. Four to six weeks after hatching, the recipients were analyzed for Bu-1 chimerism. The results demonstrate that B cell precursors are exclusively present in the Bu-1+ population of 14-day embryonic spleen, whereas the Bu-1+ macrophage subpopulation can be repopulated by either the Bu-1+ or the Bu-1- fraction of these embryonic cells. Bone marrow cells from young chickens could also repopulate the Bu-1+ macrophage subset but not the B cell compartment, thus confirming previous data that postnatal bone marrow does not contain B cell precursors. These results demonstrate that all B cell precursors in the 14-day embryonic spleen carry the Bu-1 antigen, and suggest that there is no lineage relationship between the Bu-1+ cells and macrophages.
authors.affiliation: Basel Institute for Immunology, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Houssaint
authors.forename: O
authors.initials: O
authors.lastname: Lassila
authors.forename: O
authors.initials: O
authors.lastname: Vainio
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis*; D001402:B-Lymphocytes / Q000032:analysis / Q000502:physiology* / Q000637:transplantation; D015415:Biomarkers / Q000032:analysis; D001853:Bone Marrow / Q000032:analysis; D016026:Bone Marrow Transplantation; D002060:Bursa of Fabricius / Q000276:immunology*; D002454:Cell Differentiation; D002642:Chick Embryo; D007519:Isoantigens / Q000032:analysis*; D013154:Spleen / Q000032:analysis / Q000637:transplantation; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000032:analysis / Q000502:physiology*
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D015415:Biomarkers; D007519:Isoantigens