Human Interferon Lambda-1 (IFNL1) Protein

Background

Interferon Lambda 1 (IFNL1), also known as IL-29, is a member of the Type III interferon family, which includes IFNL1, IFNL2 (IL-28A), and IFNL3 (IL-28B), and more recently discovered IFNL4. These cytokines are involved in antiviral immunity and have significant overlap in function with Type I interferons (such as IFN-α and IFN-β), but with distinct cellular targeting. IFNL1 plays a key role in the innate immune response, especially in protecting epithelial barriers, such as those found in the lungs, intestines, and liver, from viral infections. Unlike Type I interferons, which have broad activity across multiple cell types, Type III interferons like IFNL1 act primarily on cells that express the interferon lambda receptor (IFNLR1), which is most commonly found on epithelial cells and some immune cells like dendritic cells. This targeted action is thought to provide a more localized antiviral defense while minimizing the systemic inflammatory responses often seen with Type I interferons.