Epigenetic Imprinting of Immunological Memory

摘要

A hallmark of the immune system is its memory for antigens it has previously encountered. The cellular basis of immunological memory is memory B and T lymphocytes. In particular, memory T helper (Th) lymphocytes express the specific antigen receptors and are epigenetically imprinted for expression of distinct genes, which mediate more effective immune response during rechallenges. The functional program of a memory Th cell is established through T cell receptor (TCR) engagement, in conjunction with instructive signals provided during its primary activation, leading to the induction of so-called lineage-specifying transcription factors which initiate the functional program by epigenetic modifications. Upon reencounter of the antigen, the functional program is recalled quickly by TCR signaling and independently of the original instructive signal. In this review, we will summarize current knowledge of epigenetic imprinting of memory Th1, Th2, and interleukin 10 (IL-10)-producing Th cells, if any, with a focus on the role of lineage-specifying transcription factors and DNA methylation.