Abstract and Introduction
Abstract
Purpose of Review: The development of lymphoid tissues as well as the ultimate differentiation of naïve and memory T cells are dependent on cytokines. In this review, we will focus on recent advances in the understanding of molecular mechanisms that regulate lymphoid development, homeostasis and tolerance.
Recent Findings: Cytokines play a critical role in the development and differentiation of lymphoid cells. In addition, newer data indicate important roles of interleukin-7 and interleukin-15 in lymphoid homeostasis and memory. Furthermore, a new family of heterodimeric cytokines comprising interleukin-12, interleukin-23 and -27 is important for differentiation of helper T cells and cell-mediated immunity. Finally the importance of tumor necrosis factor superfamily members in the development of lymphoid organs has recently been elucidated and will be discussed in detail.
Summary: New cytokines and receptors continue to be identified. The discovery and characterization of cytokines, their receptors and signaling molecules will provide a more complete understanding of normal lymphoid development, differentiation and function. In addition, this knowledge should improve our understanding of the pathogenesis of immunological diseases and hopefully will provide new treatment strategies.
Introduction
Lymphoid development and differentiation is carefully regulated at all steps by diverse cytokines. Early steps of lymphoid development and even the development of lymphoid tissues are dependent upon cytokines, as is the ultimate differentiation of naïve and memory T cells. In this review, we will focus on recent advances in our understanding of the roles of cytokines in regulating lymphocyte development and differentiation. We will emphasize cytokines that utilize the common
chain (
c), namely, interleukin-2, 4, 7, 9, 15 and 21; interleukin-12 and the related cytokines interleukin-23 and 27; and tumor necrosis factor (TNF) family members.