4-1BB signaling beyond T cells

摘要

Originally discovered as a T cell-activating molecule,4-1BB(CD137)is now also recognized as an activator of non-T cells,thus imparting a new dimension to its potential in vivo effects.4-1BB expression is seen on a variety of non-T cells including activated dendritic cells(DCs),monocytes,neutrophils,B cells and natural killer(NK)cells,and promotes their individual effector functions.The T cell-and non-T cell-activating ability of 4-1BB may be the basis of its powerful anti-cancer,anti-autoimmune and anti-viral effects.Here we discuss the consequence and importance of 4-1BB signaling in non-T cells.We consider its effects on immune regulation,and the distinct and/or overlapping pathways involved in these responses,as well as possible therapeutic applications.