[Comparison of intracellular and extracellular particles of the vaccinia virus]

The construction of recombinant vaccinia viruses (VV) is definitely a promising approach to develop vaccines for pets. To produce safer VV recombinant vaccines, it is necessary to understand the pathogenesis of VV infection. The goal of this study was to compare the biological properties of the extracellular and intracellular infectious particles of VV. Four biological properties were investigated: (i) the binding into cellular receptor(s); (ii) the mechanism of entry; (iii) the resistance to neutralisation by antibodies; (iv) the resistance to complement lysis. The results obtained in this study emphasize the differences existing between the two infectious forms of VV and demonstrate the adaptation of the extracellular particle to its role of virus dissemination in vivo. The results of this study implicate that VV strains used as expression vector in vaccinology should be deleted for genes required for EEV morphogenesis.