Immunoglobulin synthesis and its induction in B-lymphoid cells.

Several aspects of synthesis and assembly of Ig molecules in small lymphocytes and in differentiated plasma cells are summarized. Some attempt has been made to analyse at the molecular level what happens on conversion of a lymphocyte to a mature cell secreting high levels of Ig. For this study LPS activation of murine B-lymphocytes into division and maturation served as a model system. A rapid rate of mitosis and high rate of H-mRNA synthesis appeared to precede the high levels of Ig production, suggesting a translational block on H-mRNA until the cell had organized its endoplasmic reticulum and matured. In vivo, with the exception of T-independent antigens, it is unlikely that B-cell maturationis an automatic sequel to division stimuli. We are largely ignorant in this area but possible regulatory signals which achieve a dissociation of B-cell division and maturation are discussed.