Recombinant HBV reporter system

An in vitro method of assessing the capacity of a substance to treat or prevent hepatitis B virus (HBV) infection comprising:

• (a) contacting a reporter cell with a recombinant HBV (rHBv);
• (b) contacting the reporter cell with the substance;
• and
• (c) analyzing a reporter gene expression by the reporter cell;
• wherein the recombinant HBV comprises a nucleic acid encoding a first fragment of a Cre recombinase;
• wherein the reporter cell comprises a nucleic acid encoding a second fragment of the recombinase;
• wherein the first fragment of the recombinase and the second fragment of the recombinase are capable of forming a functional recombinase;
• wherein the reporter cell comprises a nucleic acid comprising a stop cassette flanked by two recombination sites fused to a reporter gene, wherein the presence of the stop cassette suppresses expression of the reporter gene;
• wherein a decrease of the reporter gene expression in the reporter cell contacted with the substance relative to reporter gene expression in the same reporter cell being contacted with said rHBV but without being contacted with said substance, is indicative for the capacity of the substance to treat or prevent HBV infection;
• wherein the first fragment of the Cre recombinase is CreN and the second fragment of the Cre recombinase is CreC.