Equid herpesvirus type 3 infection produces membrane-associated and secreted forms of glycoprotein G that are not required for efficient cell-to-cell spread of the virus in vitro

LOSINNO, ANTONELLA; VISSANI, MARÍA ALDANA; SANCHEZ, DIEGO; DAMIANI, ARMANDO MARIO

ARCHIVES OF VIROLOGY

SPRINGER WIEN

Año: 2023 vol. 168

0304-8608

The equid alphaherpesvirus type 3 (EHV-3) ORF 70 gene encodes glycoprotein G (gG), which is conserved in the majority of alphaherpesviruses. This gG is located in the virus envelope with the characteristic of being secreted into the culture medium after proteolytic processing. Alphaherpesviruses’s gG 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 versions of the virus, gG was detectable in lysates of infected cells, its supernatants and purified virions. A 100-, 60-, and 17-kDa protein 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 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 to assess whether it has a function in modulating the host immune response.