ILâ28A/Interferon-lambda 2) is a type III interferon that is upregulated in response to viral infection. It acts primarily on epithelial cells through a receptor complex that contains IL-10 R beta and IL-28 R alpha/IFN-lambda R1. IL-28A promotes the Th1 polarization of dendritic cells in the airway (e.g. production of IL-12 p70 and IFN-gamma) and inhibits Th2 and Th17 mediated inflammation. In the liver, however, the IL-28A induced Th1 cytokine response contributes to inflammation in T cell mediated hepatitis. IL-28A additionally exhibits anti-tumor activity, in part by enhancing IL-12 dependent anti-tumor CTL responses. In contrast, it is upregulated in invasive bladder cancer where it promotes tumor cell migration.