Tumor necrosis factor (TNF) superfamily is a rapidly growing family of
cytokines that interacts with a corresponding superfamily of receptors.
Liga- receptor interactions of this superfamily are involved in numerous
biological processes ranging from hematopoiesis to pleiotropic cellular
responses, including activation, proliferation, differentiation, and
apoptosis. The particular response depends on the receptor, the cell
type, and the concurrent signals received by the cell. Worldwide
interest in the TNF field surged dramatically early in 1984 with the
cloning and defining of the profound cellular effects of the first
member of this family, TNF . Subsequently, the major influence of TNF on
the development and functioning of the immune system was established.
Today, over 20 human TNF ligands and their more than 30 corresponding
receptors have been identified. Few receptors still remain orphans. What
has emerged over the years is that most TNF ligands bind to one distinct
receptor and some of the TNF ligands are able to bind to multiple TNF
receptors, explaining to some extent the apparent disparity in the
number of TNF receptors and ligands. Yet, in spite of some redundancy in
TNF ligand/receptor interactions, it is clear that in vivo spatial,
temporal, and indeed cell- and tissue-specific expression of both
ligands and their receptors are important factors in determining the
precise nature of cellular, physiological and pathological processes
they control. TNF superfamily has been the most highly investigated area
of basic medical research for over two decades.
