Structural heterogeneity of murine IgD during ontogeny

We have studied the expression of the two membrane delta heavy chains (delta 1 and delta 2) and the two native IgD structures (IgDI and IgDII) in neonatal mice. Both delta-chains appear simultaneously during development and neonatal mice, like adults, express equal amounts of delta 1 and delta 2. IgDI and IgDII also appear simultaneously during ontogeny and in the same ratio as expressed by adult mice of the same strain. Thus, when IgD first appears during ontogeny it shows the same structural heterogeneity as observed in adult mice.