Understanding hepatitis B virus dynamics and the antiviral effect of interferon-a treatment in humanized chimeric mice
Whereas the mode of action of lamivudine (LAM) against hepatitis B virus (HBV) is well established, the inhibition mechanism(s) of interferon-α are less completely defined. To advance our understanding, we mathematically modelled HBV kinetics during 14-day pegylated interferon-α-2a (pegIFN), LAM or pegIFN+LAM treatment of 39 chronically HBV-infected humanized uPA/SCID chimeric mice.
Serum HBV DNA and intracellular HBV DNA were measured frequently. We developed a multicompartmental mathematical model and simultaneously fit it to the serum and intracellular HBV DNA data..
Unexpectedly, even in the absence of an adaptive-immune response, a biphasic decline in serum HBV DNA and intracellular HBV DNA was observed in response to all treatments. Kinetic analysis and modeling indicate that the 1st phase represents inhibition of intracellular HBV DNA synthesis and secretion which was similar under all treatments with overall mean efficacy of 98%. In contrast, there were distinct differences in HBV decline during the 2nd phase which was accounted for in the model by a time-dependent inhibition of intracellular HBV DNA synthesis with the steepest decline observed during pegIFN + LAM (1.28/d) and the slowest (0.1/d) during pegIFN monotherapy.
Reminiscent of observations in patients treated with pegIFN and/or LAM, a biphasic HBV decline was observed in treated humanized mice in the absence of adaptive immune response. Interestingly, combination treatment does not increase the initial inhibition of HBV production, but rather enhanced 2nd phase decline providing insight into the dynamics of HBV treatment response and the mode of action of interferon-α against HBV.