Characterization of the CDR3 region of rearranged α heavy chain genes in human fetal liver

Abstract

SUMMARY The human fetal liver is an early site for B cell development. Pre B cells are first detectable in human fetal life at 8 weeks of gestation, when the rearrangement of the μ heavy chain genes starts. In this study we characterize the CDR3 region of rearranged α heavy chain transcripts from four human fetal livers ranging from 8 to 11 weeks of gestation. Each fetal liver showed a limited number of variations in CDR3 sequences compared with adult peripheral blood mononuclear cells (PBMC). Sequence analysis of 91 clones demonstrated that there was no preference for the usage of a certain JH gene segment, whereas a preference for usage of DH family genes, DXP and DLR, was seen in most cases during early fetal life. This is the first study where rearranged α heavy chain genes in fetal liver have been characterized. Our data suggest that the usage of JH genes is random, while there is a preference for DH family genes in human fetal liver.