The effect of an immunoglobulin mu transgene on B cell maturation.
In mu 17.2.25-transgenic (M54) mice the absolute number of surface IgM (sIgM) B cells in lymphoid organs is drastically reduced compared to normal C57BL/6 mice and a high frequency of B cells express the immunoglobulin (Ig) encoded by the transgene rather than endogenous Ig on the surface. To determine the effect of a mu transgene on B cell development, adoptive cell transfers were performed using mu transgenic (M54) bone marrow and fetal liver cells. The data presented support the following conclusions: (a) adult transgenic bone marrow contains functional B cell precursors able to mature and repopulate the spleen and peritoneum of recipient mice. The relative frequency of transgene (sIgMa) and endogenous (sIgMb) surface sIgM-positive B cells reconstituted by transgenic bone marrow in allotype-matched C57BL/6 recipients is the same as in the M54 donors; (b) serum analysis indicates that transgenic bone marrow donor cells can reconstitute B cells in congenic and severe combined immunodeficient (SCID) recipient mice; (c) transgenic fetal liver cells are not a richer source of precursors for B cells expressing endogeneous Ig; (d) in transgenic mice sIgM+ B cells are not restricted to the CD5+ phenotype, however, the relative frequency of sIgMb B cells that are CD5+ is higher in transgenic than normal mice; and (e) bone marrow cells from adult normal and transgenic mice are able to generate CD5+ B lymphocytes in the spleen and peritoneum of allotype-congenic and neonatal SCID recipient mice. The results indicate that the presence of a complete mu heavy chain transgene does not result in a selective developmental block of "conventional" bone marrow-derived pre-B and B cells.
Iacomini
J
J
Tufts University School of Medicine, Department of Pathology, Boston, MA 02111.
Imanishi-Kari
T
T
D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology*; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D018956:CD5 Antigens; D005333:Fetus / Q000276:immunology; D005803:Genes, Immunoglobulin; D006412:Hematopoietic Stem Cells / Q000276:immunology; D007075:Immunoglobulin M / Q000032:analysis / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
D015703:Antigens, CD; D018956:CD5 Antigens; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell