Virus inactivation of plasma-derived proteins by pasteurization in the presence of guanidine hydrochloride

BACKGROUND: Viruses, among them parvovirus B19 and other small, nonenvelope d viruses, may be present in human blood and may contaminate plasma-derived therapeutics. Efficient inactivation or removal of such viruses, especiall y parvoviruses, represents a current problem and corresponding technologies are under investigation. In this report, such a technology is described. STUDY DESIGN AND METHODS: A recently developed pasteurization of human apol ipoprotein A-I (apoA-I), which is performed at 60 degreesC for 10 hours in the presence of guanidine hydrochloride (GdnHCl), was validated by using a series of model viruses, including members of the families parvoviridae and picornaviridae. The model viruses were spiked into the apoA-I- and GdnHCl- containing solutions, and virus inactivation was evaluated by infectivity a ssays in cell cultures. The mechanism of virus inactivation was studied by virus sedimentation analysis using the picornavirus model. RESULTS: All viruses tested were inactivated to levels below the limit of d etection, although different inactivation kinetics were obtained for the di fferent viruses. The mechanism of virus inactivation by this pasteurization was disassembly of the virus particles into single proteins or small nonin fectious viral subunits. CONCLUSION: The pasteurization validated in this report has the potential t o inactivate a wide range of transfusion-relevant viruses including parvovi ruses and picornaviruses.