The Common γc-Cytokines and Transplantation Tolerance

Transplant rejection,like tolerance,is a T cell-dependent event.There is compelling evidence to suggest thatinduction of transplant tolerance is an actively learned process in which T cells need to engage with thealloantigens in order to learn to tolerate the ailograft.A family of cytokines whose receptors use the same IL-2receptor γc chain(also called the common γc)plays an important role in regulating multiple aspects of thealiograft response(i.e.rejection vs.tolerance).It is undeniable that γc cytokines can drive clonal expansion andeffector maturation of alloreactive T cells,and therefore,targeting such cytokines or their receptor componentsremains an attractive way of blocking transplant rejection.However,we just started to appreciate that γccytokines also regulate the acquisition of transplant tolerance via programming activated T cells for apoptoticcell death and via guiding the evolution of regulatory T cells.Thus,understanding precisely the role of γccytokines in regulating T cell homeostasis and T cell regulation is critically important in the induction oftransplant tolerance.Cellular & Molecular Immunology.2004;1(3):167-172.