DISCLAIMER: The views presented in this article do not ncecessarily reflect those of the Food and Drug Administration.
Quantification of hepatitis B virus genomes and infectivity in human serum samples
Version of Record online: 1 SEP 2006
Volume 46, Issue 10, pages 1829–1835, October 2006
How to Cite
Hsia, C. C., Purcell, Robert H., Farshid, M., Lachenbruch, Peter A. and Yu, M.-ying W. (2006), Quantification of hepatitis B virus genomes and infectivity in human serum samples. Transfusion, 46: 1829–1835. doi: 10.1111/j.1537-2995.2006.00974.x
- Issue online: 21 SEP 2006
- Version of Record online: 1 SEP 2006
- Received for publication December 5, 2005; revision received March 21, 2006, and accepted March 22, 2006.
BACKGROUND: Hepatitis B virus (HBV) infections are still a major health issue, with approximately 350 million people chronically infected with HBV worldwide. Information about the minimum copy number of HBV genomes required for infection would be useful as a reference for drug and vaccine development; for monitoring HBV patients during treatment; for screening of blood, organ, and tissue donors; and for regulating nucleic acid amplification assays for HBV.
STUDY DESIGN AND METHODS: Serum samples from chronic carriers (hepatitis B surface antigen–positive and antibody to HBV core antigen–positive) of the three most common subtypes of HBV were studied; their infectivity titers had been evaluated previously in chimpanzees. The genotypes of the HBV samples were determined by DNA sequences and type-specific amino acids of the S gene of HBV. Copy numbers of HBV DNA were quantified by real-time TaqMan polymerase chain reaction (PCR) and by nested PCR applied to limiting dilutions. The copy number determined for each inoculum was compared with previously defined chimpanzee infectivity titers.
RESULTS: The genotypes of the HBV adw, ayw, and adr inocula were A, D, and C, respectively. The concentration of HBV DNA was determined to be 5.4 × 109, 2.5 × 109, and 3.1 × 108 genome equivalents (geq) per mL for serum samples containing the adw, ayw, and adr, respectively. The chimpanzee infectivity titers per milliliter of these initial HBV-containing serum samples were previously determined to be 107.5 for adw, 107.5 for ayw (MS-2 strain), and 108 for adr.
CONCLUSION: The minimal copy number of HBV DNA in chronic carriers of HBV that can infect the chimpanzee model was estimated to be from 3 to 169 geq based upon the three well-characterized inocula.