Effects of Hydrostatic Pressure on Viruses

In several animal viruses, hydrostatic pressure causes inactivation with maintenance of immunogenicity. This chapter describes in detail how high pressure has been used to tackle basic and applied problems in virus biology. The contribution of protein folding and protein-nucleic acid interactions to virus assembly has been evaluated in many bacterial, plant, and animal viruses. Upon interaction with host cells, the conformations of the coat proteins and envelope glycoproteins have to change, which on one hand leads to noninfectious particles and on the other may lead to the exposure of previously occult epitopes, important for vaccine development. These irreversible conformational changes evoked by high pressure that resemble the changes that occur in vivo are discussed in the chapter for most of the viruses. It has been found that high pressure inactivates the enveloped influenza and Sindbis viruses by trapping the particles in the fusion intermediate state. The high titers of the neutralizing antibodies elicited by pressure-inactivated viruses indicate that hydrostatic pressure can be used to prepare whole-virus immunogens. The substantial evidence that high pressure traps viruses in the fusion intermediate states (found with alphaviruses, influenza virus, retroviruses, etc.), not infectious but highly immunogenic, is very promising for vaccine development.