Immunoglobulin heavy-chain class switching in a pre-B cell line is accompanied by DNA rearrangement

Abstract
Switching of an Abelson virus-transformed mouse lymphoid cell line from Ig .mu. to .gamma.2b H chain synthesis in vitro is accompanied by loss of DNA sequences between the JH [H chain, J region] and C.gamma.2b [constant region of IgG2b] gene segments, and thus cannot be explained by differential RNA processing. The L-chain loci of both .mu.- and .gamma.2b-producing cell clones are in the embryonic configuration, which indicates that class switching can occur in pre-B cells.