Equine herpesvirus type 3 (EHV-3) synthesizes membrane-associated and secreted forms of glycoprotein G which are not required for efficient virus cell-to-cell in vitro spread

ARMANDO DAMIANI; ANTONELLA LOSINNO

Workshop; The Inaugural Meeting & 1 st Workshop of International Animal Herpesvirus Research Center; 2022

International Animal Herpesvirus Research Center

The equine herpesvirus type 3 (EHV-3) ORF 70 gene encodes glycoprotein G (gG), which is conserved in the majority of alphaherpesviruses. gG is located in the virus envelope and, in some viruses, it is also secreted after proteolytic processing. The gGs of alphaherpesviruses modulate the host antiviral immune response by interacting with chemokines. The aim of this study is to identify and characterize EHV-3 gG. By constructing gG-tagged version of the virus, gG was detectable in lysates of purified virions, infected cells and its supernatants. A 110-kDa full length and 17-kDa membrane bound forms were detected in viral particles while a 60 kDa form was identified in supernatants of infected cells. The role of EHV-3 gG in the viral infection cycle was assessed by the construction of a gG-minus EHV-3 mutant and its gG-positive revertant. When growth characteristics in equine dermal (ED) fibroblast cell line were compared, the plaque size and the growth kinetics of the gG-minus mutant were similar to the revertant virus indicating that EHV-3 gG has not a role neither in direct cell-to-cell transmission nor virus proliferation of EHV-3 in tissue culture. The identification and characterization of EHV-3 gG presented here provides a solid background for further studies on the function of this gene in modulating the host inmune response.