被感染的黑猩猩体内HBV模板的扩展和收缩

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Expansion and contraction of the hepatitis B virus transcriptional template in infected chimpanzees
Stefan F. Wieland * , Hans Christian Spangenberg *  , Robert Thimme * , Robert H. Purcell  and Francis V. Chisari * ¶

*Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037; and Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8009

Contributed by Francis V. Chisari, December 18, 2003


We have previously shown that hepatitis B virus (HBV) replication is controlled by noncytolytic mechanisms that depend primarily on the effector functions of the CD8+ T cell response, especially the production of IFN- in the liver. The mechanisms that control the nuclear pool of viral covalently closed circular DNA (cccDNA) transcriptional template of HBV, which must be eliminated to eradicate infection, have been difficult to resolve. To examine those mechanisms, we quantitated intrahepatic HBV cccDNA levels in acutely infected chimpanzees whose virological, immunological, and pathological features were previously described. Our results demonstrate that the elimination kinetics of the cccDNA are more rapid than the elimination of HBV antigen-positive hepatocytes during the early phase of viral clearance, and they coincide with the influx of small numbers of IFN- producing CD8+ T cells into the liver. In contrast, terminal clearance of the cccDNA is associated with the peak of liver disease and hepatocellular turnover and with a surge of IFN- producing CD8+ T cells in the liver. Collectively, these results suggest that cccDNA clearance is a two-step process mediated by the cellular immune response. The first step reduces the pool of cccDNA molecules noncytolytically, probably by eliminating their relaxed circular DNA precursors and perhaps by destabilizing them. The second step enhances this process by destroying infected hepatocytes and triggering their turnover. Surprisingly, despite this multipronged response, traces of cccDNA persist indefinitely in the liver, likely providing a continuous antigenic stimulus that confers lifelong immunity.



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Abbreviations: cccDNA, covalently closed circular DNA; pgRNA, pregenomic RNA; HBV, hepatitis B virus; DHBV, duck HBV; WHV, woodchuck hepatitis virus; PCNA, proliferating cell nuclear antigen; Chn, chimpanzee n; sALT, serum alanine aminotransferase.
S.F.W. and H.C.S. contributed equally to this work.

Present address: University of Freiburg, 79085 Freiburg, Germany.

¶ To whom correspondence should be addressed. E-mail: [email protected].