Cell Surface Immunoglobulin: XXI. Appearance of IgD on Murine Lymphocytes During Differentiation¹

The differentiation of Ig-bearing lymphocytes in adult mice was studied by monitoring the appearance of IgD relative to IgM on the surface of splenocytes obtained from lethally irradiated animals reconstituted for various periods of time with adult bone marrow cells, neonatal splenocytes, or Ig^- adult splenocytes. It was found that IgM appears before IgD on differentiating lymphocytes. Furthermore, the rate of appearance of IgD during differentiation of adult cells is similar to that observed with neonatal cells.