Complicated, Critical and Elusive Role of IFN-λ

Abstract

IFN-λ are newly described cytokines classified as type III interferon composed of IFN-λ1, IFN-λ2, IFN-λ3 (also named as IL29, IL28A, IL28B). IFN-λs signal through the IFN-λR complex consisting of a unique ligand-binding chain, IFN-λR1 and an IL-10 related cytokine receptors shared accessory chain, IL-10R2 and activate primarily JAK-STAT pathway to induce antiviral, antitumor, anti-proliferative, innate or adaptive immunity. The crystal structure of IFN-λ resembles topologically to the IL-10 family of cytokines. Induction of IFN-λ genes expression is to some degree similar to IFN-α through TRIF, RIG-I or IRF7 pathway whereas this remains under exploration. IL28B polymorphisms are linked to spontaneous eradication of HCV and outcomes of recombinant therapy and these implicate the use of IFN-λ as a more effective therapeutic alternative for HCV infection compared with the current IFN-α. In this article, we provide a comprehensive review of IFN-λ which is still elusive with large amounts of mechanisms unclarified.