Many cytokines exist within structurally related families. This is well-recognized in the case of the tumor necrosis factor (TNF) family of ligands, which comprises three adjacent, closely related genes within the major histocompatibility complex (MHC) region on chromosome 6 and several other genes on a variety of chromosomes, which continue to be uncovered. More recently, the T-cell derived cytokine IL-17 was shown to be the prototype for a new family of cytokines which so far comprises IL-17A to IL-17E, a further example is to be found in the IL-1 family. These families are defined according to structural similarities in the encoded proteins. The recently described cytokines discussed in this chapter are largely of poorly defined function, but it appears that the IL-10 homologues are not functionally similar. The characteristic 6-helical structure of IL-10 seems to be conserved throughout all the homologues, but the F-helix is the region of greatest similarity, being highly conserved between all six proteins.
All Science Journal Classification (ASJC) codes
- Immunology and Microbiology(all)