| Maek's Disease (MD) is a transmissible herpesvirus infection that is characterized by paralysis, T-cell lymphoma formation and immunosuppresion in chickens. The causative agent, Marek's Disease virus (MDV), is a cell-associated alphaherpesvirus, sub-species Mardivirus. MD is controlled in commercial poultry production through vaccination, but field strains of MDV continue to evolve in virulence. The most efficacious vaccine commercially available is CVI988 (Rispens) that was developed as a vaccine after attenuation in cell culture at passage 33 (p33). As CVI988 vaccines from different suppliers vary in efficacy, we sought to construct a bacterial artificial chromosome (BAC)-bases infectious clone of low passage (<p25). DNA from p19 CVI988 was obtained from the Central Veterinary Institute, Lelystad via a collaborator in France. This DNA was co-transfected into CEF along with BAC transfer vector (pDS-HA-1), passaged in selection, and subsequent BAC-containing viruses were electroporated into E.coli to give rise to CVI988-BAC clones. One particular clone, CVI988-BAC, 699-2 (isolated from chicken... |
