Woodchuck hepatitis virus (WHV) is an established model for human hepatitis B virus. The kinetics of virus and host responses in serum and liver during acute, self-limited WHV
infection in adult woodchucks were studied. Serum WHV
DNA and
surface antigen (WHsAg) were detected as early as 1 to 3 weeks following experimental
infection and peaked between 1 and 5 weeks postinfection. Thereafter, serum WHsAg levels declined rapidly and became undetectable, while WHV
DNA levels became undetectable much later, between 4 and 20 weeks postinfection. Decreasing
viremia correlated with transient liver injury marked by an increase in serum
sorbitol dehydrogenase (SDH) levels. Clearance of WHV
DNA from serum was associated with the normalization of serum SDH. Circulating
immune complexes (CICs) of WHsAg and
antibodies against WHsAg (anti-WHs) that correlated temporarily with the peaks in serum
viremia and WHs antigenemia were detected. CICs were no longer detected in serum once free anti-WHs became detectable. The detection of CICs around the peak in serum
viremia and WHs antigenemia in resolving woodchucks suggests a critical role for the humoral immune response against WHsAg in the early elimination of viral and subviral particles from the peripheral blood. Individual kinetic variation during WHV
infections in resolving woodchucks infected with the same WHV inoculum and dose is likely due to the outbred nature of the animals, indicating that the onset and magnitude of the individual immune response determine the intensity of virus inhibition and the timing of virus elimination from serum.