IFN-λ-1,-2, and -3 (also known as IL-29, IL-28A and IL-28B respectively) are distantly related to the IL-10 family of interferons. All three IFN-λs use a distinct receptor system composed of an IFN-λR1 subunit (also called CRF2-12) and IL-10R2 subunit (also called CRF2-14). Signaling through this receptor system induces antiviral defense similar but distinct than the type I Interferons.
