Virus inactivation and protein recovery in a novel ultraviolet-C reactor

Background and Objectives Ultraviolet-C (UVC) irradiation is a viral-inactivation method that was dismissed by many plasma fractionators as a result of the potential for protein damage and the difficulty in delivering uniform doses. A reactor with novel spiral flow hydraulic mixing was recently designed for uniform and controlled UVC treatment. The objective of this study was to investigate virus inactivation and protein recovery after treatment through the new reactor. Materials and Methods Virus- and mock-spiked Alpha(1)-proteinase inhibitor (Alpha(1)-PI) solutions were treated with UVC. The virus samples were assayed for residual infectivity and amplified by the polymerase chain reaction (PCR). The mock-spiked samples were assayed for protein integrity. Results Greater than 4 log(10) of all test viruses were inactivated, regardless of the type of nucleic acid or presence of an envelope. Unlike previous studies, viruses with the smallest genomes were found to be those most sensitive to UVC irradiation, and detection of PCR amplicons greater than or equal to 2.0 kb was correlated to viral infectivity. Doses that achieved significant virus inactivation yielded recovery of > 90% protein activity, even in the absence of quenchers. Conclusions The results demonstrate the effectiveness of UVC treatment, in the novel reactor, to inactivate viruses without causing significant protein damage, and confirm the utility of large PCR amplicons as markers for infectious virus.