The three members of this family, namely IFN-lambda1, -lambda2, and -lambda3 (also known as IL-29, IL-28A, and IL-28B) are part of the type III family of interferons. IL-29/IFN-λ1 interacts with the heterodimeric cytokine receptor composed of IL10R2 and IFNLR1, expressed on epithelial cells and hepatocytes. Signaling through this receptor system induces antiviral activity similar but distinct from the type I Interferons. The type III interferons have been reported to induce dendritic cell-mediated expansion of Foxp3+ regulatory T cells.