Photochemical inactivation of duck hepatitis B virus in human platelet concentrates: A model of surrogate human hepatitis B virus infectivity

Background: Photochemical decontamination of platelet concentrates (PCs) has been demonstrated by the use of 8-methoxypsoralen and ultraviolet A light. Systems for studying the inactivation of blood-borne viruses facilitate the evaluation of photochemical decontamination protocols. Study Design and Methods: Duck hepatitis B virus (HBV), a model for human HBV, was adapted for the study of hepadnavirus inactivation. A highly specific in vitro infectivity assay used primary duck hepatocyte cultures and was followed by the detection of replicated duck HBV sequences. Results: Duck HBV-infected primary duck hepatocyte cultures produced authentic infectious virus, High-titer (>10(9) virus genome equivalents/mL) duck HBV-infected sera were completely inactivated in serum or PCs by the use of 100 mu g per mL of 8-methoxypsoralen(en and 70 J per cm(2) of ultraviolet A light. Intracellular duck HBV (>4.2 log(10)) in PCs was also inactivated. Culture results were confirmed by a sensitive duckling infectivity assay that indicated that 6.3 log(10) of infectious duck HBV had been inactivated by photochemical decontamination. Conclusion: The sensitivity of the culture assay was comparable to that of the duckling assay using polymerase chain reaction gene amplification to detect duck HBV. Duck HBV inactivation in PCs was dependent on the dose of ultraviolet A light and independent of 8-methoxypsoralen concentrations of 100 to 300 mu g per mL: 100 mu g per mt 8-methoxypsoralen inactivated 4 to 5 log(10) of virus in conjunction with 20 to 40 J per cm(2) of ultraviolet A light. The polymerase chain reaction-enhanced duck HBV culture system has utility rn optimizing photochemical decontamination protocols.