title: Differentiation of bone marrow-derived lymphocytes.
abstract: Murine lymphocytes were enzymatically radioiodinated and the class of immunoglobulin (isotype) on the cell surface was studied as a function of differentiation and ontogeny. The results indicate that IgM is the first isotype to appear and that IgD is subsequently acquired. A proportion of IgM-bearing cells also bear IgD. The acquisition of IgD does not appear to be under the influence of the thymus or of exposure to antigen. The observations suggest a sequence of differentiation steps in which B-cells first express IgM then acquire IgD (to become "double bearers"), and eventually lose IgM. The relationship of the IgD-bearing cells to the IgG-bearing memory cells has not yet been established. The implications of these findings with regard to function and genetic organization are discussed.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D051379:Mice; D011947:Receptors, Antigen, B-Cell; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology
chemical_list: D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell