title: Ontogeny of Ia and IgD on IgM-bearing B lymphocytes in mice.
abstract: We used immunofluorescence to examine the developmental relationship of Ia and IgD on B cells. Pre-B cells in fetal liver did not express Ia. Only very few surface IgM-positive (sIgM+) B cells in fetal spleen were found to be Ia+ and were weakly stained for Ia. After birth there was a linear increase in the proportion of sIgM+ spleen cells which expressed Ia, reaching 95% by 9 days. Adult bone marrow also contains a sizeable proportion of sIgM+ Ia- cells. Unstimulated cells from fetal or newborn liver and spleen expressed Ia at the same rate in culture. Anti-Ia antisera suppressed the LPS-induced differentiation of IgM and IgG plasma cells in cultures of neonatal lymphocytes. Ia was also detected on IgM and IgG plasma cells in vitro suggesting that lipopolysaccharide (LPS)-stimulated B cells by may express Ia antigens, induced by LPS, or appearing as part of normal differentiation. IgD did not appear on sIgM+ cells until 3 days of age and then rose slowly to reach adult levels later than Ia antigens.
mesh_terms: D000375:Aging; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D002455:Cell Division / Q000187:drug effects; D006649:Histocompatibility Antigens; D007072:Immunoglobulin D; D007075:Immunoglobulin M; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000166:cytology; D051379:Mice; D008815:Mice, Inbred Strains; D010950:Plasma Cells / Q000276:immunology; D011947:Receptors, Antigen, B-Cell; D013154:Spleen / Q000166:cytology
chemical_list: D006649:Histocompatibility Antigens; D007072:Immunoglobulin D; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D011947:Receptors, Antigen, B-Cell