Four of Five RAG-Expressing JCκ −/− Small Pre-BII Cells Have No L Chain Gene Rearrangements : Detection by High-Efficiency Single Cell PCR

Abstract

Single cell PCR assays have been further developed that detect over 80% of all VκJκ, VκRS, and VλJλ rearrangements at efficiencies between 70% and 90%. These IgL chain gene rearrangement assays were used with small pre-BII cells that develop in comparably high numbers in the bone marrow of wild-type, Cκ-deficient, and JCκ-deficient homozygous and heterozygous mice. In all of these mice, only 15%–25% of all small pre-BII cells carry VλJλ rearrangements. These results confirm that λL chain gene rearrangements occur independently of κL chain gene rearrangement and expression. They also show that a large part of the small pre-BII cells that express the rearrangement machinery can develop without IgL chain gene rearrangements.