Viral inactivation in von Willebrand factor preparations via UVC irradiation: an experimental approach

[Objective] To evaluate the efficacy of ultraviolet-C (UVC) irradiation in inactivating porcine parvovirus (PPV), encephalomyocarditis virus (EMCV), pseudorabies virus (PRV) and vesicular stomatitis virus (VSV) within von Willebrand factor (vWF) preparations. [Methods] An ultraviolet inactivator (254 nm primary wavelength) was employed to optimize UV exposure dosages for the samples, and the initial test groups were set at five irradiation gradients: 100, 200, 400, 1 000, and 1 500 J/m2 gradients. Based on the results of the preliminary experiments, subsequent formal experiments implemented refined dosage parameters at 100, 125, 150, 175, and 200 J/m2. Virucidal efficacy against various pathogenic strains was evaluated via cytopathic effect (CPE) observation methodology, while simultaneously quantifying von Willebrand factor antigen levels (vWF∶Ag) and collagen-binding activity (vWF∶CBA) using enzyme-linked immunosorbent assays (ELISA) and automated coagulation analysis systems before and after UVC treatment. [Results] The results showed that > 100 J/m2 UVC irradiation achieved a≥4.0 log reduction factor in vWF. For vWF antigen, retention rates were observed to be 93.67%, 91.72%, 93.54%, 79.05%, and 85.50% at UVC doses of 100, 125, 150, 175, and 200 J/m2, respectively. Similarly, the retention rates of vWF collagen-binding activity were 81.11%, 87.81%, 86.15%, 73.73%, and 73.72% under the same dose conditions. [Conclusion] Considering both inactivation efficacy and functional preservation while ensuring safety and effectiveness, 100-150 J/m2 represents the optimal inactivation dose.