Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5551891 | Antiviral Research | 2017 | 8 Pages |
â¢We constructed two recombinant vaccines against IBDV based on two MDV1 strains.â¢The two recombinant MDVs exhibited different replication properties.â¢The r814-VP2 virus expressed higher levels of VP2 than rLMSâ³Meq-VP2.â¢The r814-VP2 virus induced stronger antibody responses against IBDV in chickens.â¢The r814-VP2 vaccine provided full protection against vvIBDV in chickens.
Attenuated strains of Marek's disease virus serotype 1 (MDV1), and the closely related herpesvirus of turkeys, are among the most potent vectors for development of recombinant vaccines for poultry. To investigate the effects of MDV1 strain characteristics on the protective efficacy of the recombinant vaccines, we developed two recombinant MDV1 vaccines for expressing the VP2 gene of infectious bursal disease virus (IBDV) based on two different MDV1 strains, the attenuated strain 814 and the Meq gene-deleted recombinant MDV1 strain rLMSâ³Meq, as the viral vectors. The r814-VP2 virus based on the 814 strain exhibited higher replication efficiency in cell culture while lower viral titers in chickens, compared to rLMSâ³Meq-VP2 derived from the rLMSâ³Meq strain. Further studies indicated that r814-VP2 produced higher levels of VP2 protein in cells and elicited stronger immune responses against IBDV in chickens than rLMSâ³Meq-VP2. After IBDV challenge, rLMSâ³Meq-VP2 provided 50% protection against mortality, and the birds that survived developed bursal atrophy and gross lesions. In contrast, r814-VP2 conferred complete protection not only against development of clinical signs and mortality, but also against the formation of bursal lesions. The results indicate that different MDV1 vector influences the protective efficacy of recombinant MDV1 vaccines. The r814-VP2 has the potential to serve as a bivalent vaccine against two important lethal pathogens of chickens.