Orchestration Of T Cell Development By Common Gamma Chain Cytokines

Cytokines serve as short-range chemical signals among cells, required for cell survival, expansion, and differentiation. They act through specific receptor complexes that are tightly controlled in expression and activate discrete intracellular signal transducers to transmit unique instructions. Cytokines are necessary to build the immune system, and for T lymphocytes, the classic effectors of cell-mediated immunity originating in the thymus, their functions in T cell progenitor maintenance, T cell differentiation, and construction of proper tissue environment for T cell production have been extensively investigated. In particular, six cytokines that signal using the gamma chain as the shared component of receptor complexes, and thus named the common gamma chain (gamma(c)) family of cytokines, are paramount for T cells, from birth to death. During development and selection for functional fitness in the thymus, T cell subsets acquire functional specificity asynchronously, with some T cells exported from the thymus as naive cells awaiting encounter of a specific pathogen, while others exit the thymus with preprogrammed function and anatomical destinations. We review the varied effects of gamma(c) cytokines during T cell development to illustrate how cytokines ultimately impart clonal and subset heterogeneity in function in the T cell lineage.