TABLE 4.

Efficiency of inverse PCR experiment: effect on estimates of predicted hepatocyte turnover

Model no.Theoretical hepatocyte turnovercComplexity of virus-cell junctions ind:Predicted hepatocyte turnover to produce the measured complexity at the indicated inverse PCR efficiency ine:
Untreated groupETV-treated groupUntreated groupETV-treated group
100%50%20%10%100%50%20%10%
2a0.70.410.730.60f1.84g6.4g13.7g0.27f0.44f>0.7h>0.7h
3b2.60.410.731.36f2.1f3.4g9.6g0.36f0.73f1.6f2.2f
  • a In model 2, cccDNA is lost during mitosis.

  • b In model 3, cccDNA survives mitosis. Hepatocytes are assumed to contain an average of 30 copies of cccDNA prior to the initiation of clearance, and cccDNA is distributed in a binomial fashion to progeny hepatocytes during mitosis.

  • c The theoretical level of hepatocyte turnover required to clear WHV infection from 100% of hepatocytes, each containing 30 copies of cccDNA, was previously defined to be 0.7 and 2.6 liver equivalents for models 2 and 3, respectively (14, 18).

  • d The complexity of virus-cell junctions present in the liver of WHV-infected control and ETV-treated woodchucks was determined as shown in Table 2.

  • e The efficiency of the inverse PCR reaction is assumed to fall within the range of 10 to 100%. The predicted cumulative hepatocyte turnover required to clear WHV infection with model 2 (cccDNA loss) or model 3 (cccDNA survival) was calculated based on the measured complexity of virus-cell junctions using the program comp10, as described in Materials and Methods, allowing for the range of efficiencies of the inverse PCR reaction. The liver was assumed to regenerate to full size after each cycle of hepatocyte killing.

  • f The predicted hepatocyte turnover based on measured complexity is less than the theoretical hepatocyte turnover for model 2 or model 3 and is not sufficient to eliminate the virus from the liver.

  • g The predicted hepatocyte turnover based on complexity is greater than the theoretical hepatocyte turnover for model 2 or model 3 and suggests that a period of random hepatocyte death and proliferation, to maintain liver cell mass, occurs prior to the clearance phase of the infection.

  • h The predicted hepatocyte turnover based on complexity was not calculated because virus replication is inhibited by ETV even prior to initiation of immune clearance.