Characterization of viral variants of HSV-1 obtained under selective pressure of sulfated polysaccharides

ARTUSO, CAROLINA; MATEU, CECILIA; PEREZ RECALDE, MERCEDES; HERMIDA, GLADYS; PUJOL CARLOS; DAMONTE, ELSA; CARLUCCI, JOSEFINA.

Ithaca, New York, USA

Workshop; 34th International Herpesvirus Workshop; 2009

Natural carrageenans are known to be potent and selective inhibitors of HSV-1 and 2. Since they are structurally similar to glysominoglycans (GAG) such as Heparan Sulfate, used by HSV to enter and infect the cell, their mechanism of action affect viral adsorption. The ¥ì/¥í- carrageenan 1C3 was used in order to obtain viral variants. For this porpous, serial passages of HSV-1 with increasing concentrations of 1C3 were made using Vero cells monolayers. After several passages, two viral variants were isolated (syn 14-1 and 17-2) and characterized regarding their cytophatic, phenotipic and pathogenic effect.  Different cell lines and primary murine tissue cultures were infected with parental and variant strains. Viral plaques with syncytial phenotype were observed in primary culture of lung and vagina; however not in all cell lines syncytium was obtained. In contrast, parental strain had always generated its typical cytopathogenicity of rounded cells.  Moreover, analysis of thermosensitivity by direct plaque assay resulted in a titer of syn 17-2 2 log higher than syn 14-1 and F when incubated at 38¨¬C. In order to study pathogenicity, Balb/c mice were infected with viral variants and F strain.  Results showed differences according to the route of inoculation used.  Mice inoculated intravaginally with syn 14-1 and syn 17-2 survived the infection and showed low levels of proinflammatory cytokines while 100% of those infected with parental strain died.  On the other hand, by intranasal inoculation dissemination was faster, reaching reproductive organs. However, histopathological analysis did not reveal significant differences between variants and F strain. Although in vitro syncytium formation was observed, it was not the case for in vivo experiments. In conclusion, viral variants obtained under selective pressure of a sulfated polysaccharide have attenuated pathogenic action and low proinflammatory cytokines activation allowing us to obtain strains that could have potential prophilactic and thepapeutic use.