title: Cytoplasmic immunofluorescence of bone marrow plasma cells producing immunoglobulins of the four IgG subclasses.
abstract: Immunofluorescence studies were performed on bone marrow samples from 21 individuals with normal or slightly elevated serum IgG levels. On the average, 40.7 percent of the IgG-positive plasma cells contained molecules of the subclass IgG; 30.6 percent had intracellular IgG2; 21.7 percent, IgG3, and 7.0 percent, IgG4. These figures were compared to the relative serum IgG subclass concentrations. The principal finding was the discrepancy between the high relative number of IgG-3 producing bone marrow plasma cells and the low relative IgG3-producing bone marrow plasma cells and the low relative IgG3 serum concentration (5.5 percent of the total IgG). It was explained by the short biologic half-life of  molecules of this subclass.
mesh_terms: D000328:Adult; D000368:Aged; D000917:Antibody Formation; D001853:Bone Marrow / Q000276:immunology*; D001854:Bone Marrow Cells; D003593:Cytoplasm / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D006207:Half-Life; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007106:Immune Sera; D007074:Immunoglobulin G; D007136:Immunoglobulins / Q000032:analysis; D008875:Middle Aged; D010641:Phenotype; D010950:Plasma Cells / Q000276:immunology*; D013194:Staining and Labeling
chemical_list: D007106:Immune Sera; D007074:Immunoglobulin G; D007136:Immunoglobulins