IgM to IgD transition

[MrMistery]

What is the molecular mechanism by which IgM to IgD transition occurs in the development of an immature naive B cell into a mature naive B cell?

[blcr11]

Apparently there are two mechanisms: class-switch recombination and alternative splicing.

http://www.pubmedcentral.nih.gov/articl ... d=16895553

Not sure if this review addresses the developmental aspects of IgD expression, though.

[MrMistery]

uhum. Thanks. CSR does not appear in this case in humans, with the exceptions noted there. That is really why I asked, cause I found in a couple of books that there is no switch signal before the delta heavy chain gene region, thus making CSR impossible.
Thus, i have my answer: alternative splicing.