title: The class of surface immunoglobulin on cells carrying IgG memory in rat thoracic duct lymph: the size of the subpopulation mediating IgG memory.
abstract: The fluorescence activated cell sorter was used to determine the class of immunoglobulin on the thoracic duct lymphocytes (TDL) which carried IgG memory. Although only about 3% of all TDL carried membrane IgG these cells accounted for most, if not all, of the adoptive IgG anti-DNP response. It is concluded that both CR+ and CR- cells mediating IgG memory in rat TDL bear the same class of membrane immunoglobulin as that secreted by their differentiated progeny. The class of membrane immunoglobulin on CR+ and CR- rat TDL was also examined. It was found that IgM+ cells, which made up over 80% of all Ig+ cells, were virtually all CR+. In contrast, the few percent of IgG+ and IgA+ cells present were to be found in both subpopulations. There was no evidence of a large population of B cells bearing exclusively heavy chains other than IgA, IgG, of IgM. The observation that some IgG+ cells as well as IgM+ cells possess a receptor for C3 appears to rule out the hypothesis that this receptor is involved in blocking a switch from IgM to IgG synthesis.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D003176:Complement C3 / Q000378:metabolism; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007075:Immunoglobulin M / Q000032:analysis; D007156:Immunologic Memory; D008196:Lymph / Q000276:immunology; D051381:Rats; D011947:Receptors, Antigen, B-Cell / Q000145:classification*; D011955:Receptors, Drug
chemical_list: D003176:Complement C3; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell; D011955:Receptors, Drug