Introduction of Type III Interferon

Similar to the type I IFNs, the type III IFNs signal as monomeric cytokines engaging one copy of each of their low-affinity and high affinity receptors. However, unlike both the type I and type II IFNs, which employ their own dedicated receptors, the IFNλs utilize one unique receptor (IFNLR1) but also one required for signal transduction by IL-10, IL-22 and IL-26 (IL10RB). The receptor-associated JAK kinases, JAK1 with IFNLR1 and Tyk2 with IL10RB are responsible for activation of the JAK/STAT pathway upon IFNl engagement of this receptor complex. As IL10RB is also common to the signaling complexes for IL-10, IL-22 and IL-26, it remains to be seen whether there is any functional cross-talk between the type III IFNs and these cytokines as a result of having a shared receptor.