Intramuscular immunization of mice with the live-attenuated herpes simplex virus 1 vaccine strain VC2 expressing equine herpesvirus 1 (EHV-1) glycoprotein D generates anti-EHV-1 immune responses in mice
© 2017 American Society for Microbiology. All Rights Reserved. Vaccination remains the best option to combat equine herpesvirus 1 (EHV-1) infection, and several different strategies of vaccination have been investigated and developed over the past few decades. Herein, we report that the liveattenuated herpes simplex virus 1 (HSV-1) VC2 vaccine strain, which has been shown to be unable to enter into neurons and establish latency in mice, can be utilized as a vector for the heterologous expression of EHV-1 glycoprotein D (gD) and that the intramuscular immunization of mice results in strong antiviral humoral and cellular immune responses. The VC2-EHV-1-gD recombinant virus was constructed by inserting an EHV-1 gD expression cassette under the control of the cytomegalovirus immediate early promoter into the VC2 vector in place of the HSV-1 thymidine kinase (UL23) gene. The vaccines were introduced into mice through intramuscular injection. Vaccination with both the VC2-EHV-1-gD vaccine and the commercially available vaccine Vetera EHVXP 1/4 (Vetera; Boehringer Ingelheim Vetmedica) resulted in the production of neutralizing antibodies, the levels of which were significantly higher in comparison to those in VC2-and mock-vaccinated animals (P < 0.01 or P < 0.001). Analysis of EHV-1-reactive IgG subtypes demonstrated that vaccination with the VC2-EHV-1-gD vaccine stimulated robust IgG1 and IgG2a antibodies after three vaccinations (P < 0.001). Interestingly, Vetera-vaccinated mice produced significantly higher levels of IgM than mice in the other groups before and after challenge (P < 0.01 or P < 0.05). Vaccination with VC2-EHV-1-gD stimulated strong cellular immune responses, characterized by the upregulation of both interferonand tumor necrosis factor-positive CD4+ T cells and CD8+ T cells. Overall, the data suggest that the HSV-1 VC2 vaccine strain may be used as a viral vector for the vaccination of horses as well as, potentially, for the vaccination of other economically important animals.
Publication Source (Journal or Book title)
Journal of Virology
Liu, S., Stanfield, B., Chouljenko, V., Naidu, S., Langohr, I., Piero, F., Ferracone, J., Roy, A., & Kousoulas, K. (2017). Intramuscular immunization of mice with the live-attenuated herpes simplex virus 1 vaccine strain VC2 expressing equine herpesvirus 1 (EHV-1) glycoprotein D generates anti-EHV-1 immune responses in mice. Journal of Virology, 91 (12) https://doi.org/10.1128/JVI.02445-16