Expression of Secreted Immunoglobulin Heavy Chain Genes and Immunoglobulin‐Secreting Cells in Human Lymphocytes

The numbers of immunoglobulin‐secreting cells in peripheral blood mononuclear cells and the expression of mRNA for secreted type of immunoglobulin heavy chains were investigated in healthy children, compared with the percentages of surface immunoglobulin‐bearing cells and the expression of mRNA for membrane‐bound type of immunoglobulin heavy chains, respectively. Although a difference between expression of μs mRNA and μm mRNA was unclear, μmRNA was well transcribed. The expression of γs mRNA or αs mRNA was markedly higher than that of γm mRNA or αm mRNA. However, although the detection methods could be of different sensitivities, the percentage of IgM‐, IgG‐, or IgA‐secreting cells was markedly low, compared with the percentage of surface IgM‐, IgG‐, or IgA‐bearing cells, respectively. Therefore, additional regulation of the pattern of the immunoglobulin gene expression may be exerted at the translational and post‐translational stages.