Cell‐cycle regulation of T‐cell responses – novel approaches to the control of alloimmunity

Summary: Alloreactive T cells undergo clonal expansion before they participate in allograft rejection. Current estimates suggest that roughly 1 in 20 peripheral T cells are alloreactive, and these cells may expand at least 20–50‐fold during an alloimmune response in vivo . The majority of immunosuppressive drugs currently used to facilitate graft survival in experimental models and in the clinic act to inhibit T‐cell proliferation. This review focuses on 1) recent advances in monitoring alloreactive T‐cell proliferation during alloimmune responses, 2) the link between cell division, anergy avoidance, and effector T‐cell differentiation, and 3) an overview of growth factor receptor‐coupled signal transduction pathways, with emphasis on key cell‐cycle regulators that may serve as potential targets for novel immunosuppressive or tolerance‐inducing strategies.