Blimp hovers over T cell immunity

Abstract

The functions of T lymphocytes are regulated by transcription factors controlling gene expression. Three studies in this issue of Immunity (Kallies et al., 2009; Rutishauser et al., 2009; Shin et al., 2009) indicate that the transcriptional repressor Blimp-1 promotes the development of short-lived effector cells and regulates clonal exhaustion.

Figure 1. Blimp-1 and the fates of T cells during viral infections

This figure portrays fates of CD8 T cells that either do or do not express Blimp-1 during a viral infection. Naïve T cells sensing antigen will secrete IL-2 and other cytokines and ultimately enter different differentiation pathways. IL-2 can stimulate expression of Blimp-1, which, in turn, will shut down IL-2 expression. Blimp-1+ cells can migrate into peripheral tissues, become short-lived effector cells under conditions of low antigen load, and become clonally exhausted under conditions of high antigen load. Some survive longer term as effector memory cells. Cells lacking Blimp-1 migrate relatively poorly into the periphery, produce IL-2, and are most of the memory cell precursors, evolving to become central memory cells.