Type 3 interferons (eg, peg-interferon lambda-1, or recombinant IL-29) Anti-viral immune responses Pneumocytes (tissue-barrier epithelial cells), dendritic cells, macrophages, neutrophils IFNλ might overcome suppression of interferons and stimulate antiviral immune responses without detrimental hyperinflammation (restricted expression pattern of IFNλ receptor 1); less inflammatory side-effects than IFNα in patients with hepatitis C virus and in influenza-infected mice Knowledge of interferon lambda biology in humans is incomplete