Preferential expression of VH5 and VH6 immunoglobulin genes in early human B-cell ontogeny.

Analysis of Ig transcripts by dot blot hybridization revealed that VH5 and VH6 RNA first occurred during the 7th week of gestation in human fetal liver. At the same time, a C lambda or C lambda-like chain was also expressed, in the absence of detectable kappa chains. In adult B cells, VH3 appears to be the dominant family expressed. Because VH5 and VH6 were located as the most proximal V genes to the JH cluster, the orderly expression of human VH genes seems to resemble the situation reported for the mouse.