Aims: To make a comparative evaluation of the effects of different stabilizers and freezing rates on structurally different viruses during lyophilization and storage.
Methods and results: Two virus strains from each of six animal virus families, including both enveloped and nonenveloped viruses, were lyophilized in (i) culture medium, (ii) with the addition of gelatine-sucrose and (iii) skim milk-sodium glutamate. All the virus suspensions were frozen (i) at -80°C or (ii) in liquid nitrogen before lyophilization. Virus titre assay after lyophilization and after 8 months storage at 4°C revealed that the efficacy of stabilizers depended on virus structure. Generally, the best protective quality for enveloped viruses was achieved with gelatine-sucrose, which best maintained their infectivity and envelope morphology. Even additive-free culture medium proved adequate for nonenveloped viruses. Differences in stabilizer efficacy were also found between virus families and were expressed immediately after lyophilization; the activity of stabilizers in the course of storage was very similar. Freezing in liquid nitrogen proved beneficial for picornaviruses.
Conclusions: The choice of an appropriate stabilizer with respect to virus type is crucial for effective lyophilization.
Significance and impact of the study: This study contributes to the establishment of general guidelines for animal virus lyophilization, with particular respect to differences in virus structure.
Keywords: animal virus lyophilization; animal virus preservation; freezing rate; stabilizer; virus structure.
© 2014 The Society for Applied Microbiology.