Interleukin 28B (IL28B)

IL28B is a class II cytokine receptor ligand related to type I interferons . These ligands play a critical role in response to microbial challenge and activate the JAK /STAT signaling system (Sheppard et al., 2003). By genomic sequence analysis, Sheppard et al. (2003) identified genes encoding IL28A , IL28B, and IL29. The deduced 200-amino acid IL28B protein is 96% identical to IL28A and 81% identical to IL29, but it shares only low homology with IL10 , IFNA2, and IL22 .

IL28B has a conserved cysteine pattern and amphipathic profile similar to other helical cytokine family members. By genomic sequence analysis, Sheppard et al. (2003) determined that the IL28B gene contains 6 exons, in contrast to the related type I IFNs, which are encoded by a single exon.