Location: Endemic Poultry Viral Diseases ResearchTitle: Protective efficacy of molecularly cloned Gallid alphaherpesvirus 3 vaccine strain 301B/1 against very virulent Marek’s disease virus challenge
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/21/2018
Publication Date: 7/21/2018
Citation: Kim, T.N., Dunn, J.R., Spatz, S.J. 2018. Protective efficacy of molecularly cloned Gallid alphaherpesvirus 3 vaccine strain 301B/1 against very virulent Marek’s disease virus challenge [abstract]. Annual International Herpesvirus Workshop, Vancouver, Canada, July 21-25, 2018.
Technical Abstract: Marek’s disease (MD), caused by Gallid alphaherpesvirus 2, is a highly contagious lymphoproliferative disease in chicken. Marek’s disease virus (MDV) has increased its virulence toward higher virulent forms because current vaccines fail to induce sterilizing immunity and efficient MDV replication can still occur in vaccinated chickens. Turkey herpesvirus (HVT) and Gallid alphaherpesvirus 3 (GaHV-3) have been developed as bivalent vaccines to synergistically improve performance as compared to the level of protection elicited by single formulations of HVT or GaHV-3 (e.g. SB-1 vaccine strain). Since in vitro passage of MD vaccine strains can result in over attenuation, we sought to secure a molecularly defined MDV vaccine strain by inserting the mini-F replicon into the genome of another GaHV-3 strain (301B/1) creating a bacterial artificial chromosome (BAC). Infectious virus was rescued from various 301B/1-BAC clones by reverse genetics techniques. Reconstituted 301B/1-BAC viruses showed growth kinetics comparable to parental 301B/1 virus. Preliminary data from a vaccine protection study using specific pathogen free chickens suggest vaccine virus reconstituted from a selected GaHV-3 301B/1 BAC exhibited an efficacious protection profile against very virulent GaHV-2 challenge. Safety and protective indices of the molecularly cloned vaccine candidate will be discussed.