Molecular mechanisms underlying the coordination of isotype switching with plasma cell differentiation are poorly understood. We show that interferon regulatory factor-4 (IRF-4) regulates both processes by controlling the expression of the Aicda and Prdm1 genes, which encode AID and Blimp-1, respectively. Genome-wide analysis demonstrated that Irf4-/- B cells failed to induce the entire Blimp-1-dependent plasma cell program. Restoration of AID or Blimp-1 expression in Irf4-/- B cells promoted isotype switching or secretion, respectively. IRF-4 was expressed in a graded manner in differentiating B cells and targeted Prdm1. Higher concentration of IRF-4 induced Prdm1 and consequently the transition from a germinal center gene expression program to that of a plasma cell. We propose a gene-regulatory network in which graded expression of IRF-4 developmentally coordinates isotype switching with plasma cell differentiation. © 2006 Elsevier Inc. All rights reserved.
Sciammas, R., Shaffer, A. L., Schatz, J. H., Zhao, H., Staudt, L. M., & Singh, H. (2006). Graded Expression of Interferon Regulatory Factor-4 Coordinates Isotype Switching with Plasma Cell Differentiation. Immunity, 25(2), 225–236. https://doi.org/10.1016/j.immuni.2006.07.009