Background. Type III interferons (IFNs) (lambda 1-3) activate similar signaling cascades as type I IFNs (alpha and beta) via different receptors. Since IFN-alpha and lymphotoxin-beta activate cytosine deamination and subsequent purging of nuclear hepatitis B virus (HBV) DNA, we investigated whether IFN-beta and -lambda may also induce these antiviral effects in differentiated HBV-infected hepatocytes.Methods. After determining the biological activity of IFN-alpha 2,-beta 1, -lambda 1, and -lambda 2 in differentiated hepatocytes, their antiviral effects were analyzed in HBV-infected primary human hepatocytes and HepaRG cells.Results. Type I and III IFNs reduced nuclear open-circle DNA and covalently closed circular DNA (cccDNA) levels in HBV-infected cells. IFN-beta and -lambda were at least as efficient as IFN-alpha. Differential DNA-denaturing polymerase chain reaction and sequencing analysis revealed G-to-A sequence alterations of HBV cccDNA in IFN-alpha, -beta, and -lambda-treated liver cells indicating deamination. All IFNs induced apolipoprotein B messenger RNA-editing enzyme-catalytic polypeptide-like (APOBEC) deaminases 3A and 3G within 24 hours of treatment, but IFN-beta and -lambda induced longer-lasting expression of APOBEC deaminases in comparison to IFN-alpha.Conclusions. IFN-beta, IFN-lambda 1, and IFN-lambda 2 induce cccDNA deamination and degradation at least as efficiently as IFN-alpha, indicating that these antiviral cytokines are interesting candidates for the design of new therapeutic strategies aiming at cccDNA reduction and HBV cure.