Blood, Vol. 93 No. 1 (January 1), 1999:
pp. 198-207
Light Chain Shifting: Identification of a Human Plasma Cell Line
Actively Undergoing Light Chain Replacement
Hirofumi Tachibana,
Hirotaka Haruta, and
Koji Yamada
From the Department of Food Science and Technology, Faculty of
Agriculture, Kyushu University, Fukuoka, Japan.
We identified an antibody-secreting human B-cell line (HTD8), which
actively replaces the production of the original 
light chain with a
new chain (light chain shifting) at a high rate. Loss of the
original rearranged light chain occurs by significantly reducing
the amount of transcript expressed. Expression of the new chain,
which replaces the original chain, occurs by rearranging new VJ
segments on a previously excluded allele. V gene usage of these new
rearrangements are biased toward V
4, V6, and V10 families, which are known to be the least
frequently used. In striking contrast to the plasma cell phenotype,
recombination activating genes, RAG-1 and RAG-2, were expressed in the
HTD8 cells and were shown to be necessary, but insufficient for
inducing expression of the new chain. These results suggest that
human plasma cells have the potential to actively undergo light chain replacement.
