Effect of anti-gamma 3 antibodies on immunoglobulin isotype expression in lipopolysaccharide-stimulated cultures of mouse spleen cells.
To test the hypothesis that gamma 3 is the pivotal isotype for sequential heavy chain switching from mu to each of the gamma isotypes, we have compared the effects of anti-gamma 3 and anti-mu antibodies on the expression of immunoglobulin isotypes in lipopolysaccharide (LPS)-stimulated cultures of mouse spleen cells. IgM-, IgG1-, IgG2b- and IgG2a-containing plasma cells were enumerated by immunofluorescence and secreted immunoglobulins were measured by radioimmunoassay. Although anti-gamma 3 and anti-mu were equally effective in inhibiting the LPS-induced differentiation of IgG3 plasma cells, anti-gamma 3 had no effect on the differentiation of IgM, IgG1, IgG2b, or IgG2a plasma cells. These results support a direct mechanism of heavy chain immunoglobulin switching.
D000818:Animals; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007130:Immunoglobulin Idiotypes / Q000276:immunology*; D007142:Immunoglobulin gamma-Chains / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D011863:Radioimmunoassay; D013154:Spleen / Q000276:immunology
D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007142:Immunoglobulin gamma-Chains; D008070:Lipopolysaccharides