A division-linked mechanism for the rapid generation of Ig-secreting cells from human memory B cells.

Abstract

Memory B cells, when re-exposed to Ag and T cell help, differentiate into Ig-secreting cells (ISC) at the same time as maintaining a residual pool of non-Ig-secreting cells with memory capabilities. To investigate the mechanism underlying this dual process, we followed the fate of human B cells activated in vitro with the T cell-derived signals CD40 ligand (CD40L), IL-2, and IL-10 using CFSE to monitor cell division. A substantial number of ISCs detected by ELISPOT, intracellular Ig staining, and Ig secretion could be generated from memory but not naive B cells. The proportion of ISCs increased with successive cell divisions and was markedly enhanced by IL-10 at each division. Within ISCs, t..