[Instability of immunoglobulin expression during differentiation induction in the human lymphoblastoid cell line RPMI-6410t].

The induction of immunoglobulin heavy chain classes switch from IgM to IgG was demonstrated in vitro in cells of RPMI-6410t line. The IgG+-sublines, formed as a result of the switch are characterized by instability of IgG synthesis. After removal of the inductor from the growth environment, IgG+ cells gradually reduce the level of secreted IgG. Such a transition to the functional rest state is likely to be connected with the convertible Ig-gene activity suppression in IgG+ cells, since after their activation by LPS IgG-secretion is partly or completely restored. The IgG+-sublines obtained may serve a convenient model for investigating the Ig-gene expression regulation in differentiated human B-cells.