title: The influence of stabilizers and rates of freezing on preserving of structurally different animal viruses during lyophilization and subsequent storage.
abstract: OBJECTIVE
  To make a comparative evaluation of the effects of different stabilizers and freezing rates on structurally different viruses during lyophilization and storage.
  
  
  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.
  
  
  CONCLUSIONS
  This study contributes to the establishment of general guidelines for animal virus lyophilization, with particular respect to differences in virus structure.
authors.affiliation: Collection of Animal Pathogenic Microorganisms, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: H
authors.initials: H
authors.lastname: Malenovská
mesh_terms: D003470:Culture Media; D005612:Freeze Drying / Q000379:methods*; D005615:Freezing; D014780:Viruses / Q000648:ultrastructure
chemical_list: D003470:Culture Media
keywords: animal virus lyophilization; animal virus preservation; freezing rate; stabilizer; virus structure