Bu-1 antigen expression as a marker for B cell precursors in chicken embryos

Publisher Website
Google Scholar
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-la and Bu-la- 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 B cells and macrophages.
Keywords