Key Gene Identified in Marek's Disease Virus

The deletion of the Meq gene significantly decreases immunosuppression in chickens caused by pathogenic Marek's disease virus, according to newly published research from two leading Chinese institutes.

7 January 2011

3 minute read

Marek's disease virus (MDV) causes an acute lymphoproliferative disease in chickens, resulting in immunosuppression which is considered to be an integral aspect of the pathogenesis of Marek's disease (MD). In the latest issue of Virology Journal, Yanpeng Li of the Chinese Academy of Agricultural Sciences in Beijing and co-authors there and at Shandong Agricultural University in Tai'an describe a recent study showed that deletion of the Meq gene resulted in loss of transformation of T-cells in chickens and a Meq-null virus, rMd5ΔMeq, could provide protection superior to CVI988/Rispens.

Results

In the present study, to investigate whether the Meq-null virus could be a safe vaccine candidate, the scientists constructed an Meq deletion strain, GX0101ΔMeq, by deleting both copies of the Meq gene from a pathogenic MDV, GX0101 strain, which was isolated in China. Pathogenesis experiments showed that the GX0101ΔMeq virus was fully attenuated in specific pathogen-free chickens because none of the infected chickens developed Marek's disease-associated lymphomas.

The study also evaluated the effects of GX0101ΔMeq on the immune system in chickens after infection with GX0101ΔMeq virus.

Immune system variables, including relative lymphoid organ weight, blood lymphocytes and antibody production following vaccination against AIV and NDV were used to assess the immune status of chickens.

Experimental infection with GX0101ΔMeq showed that deletion of the Meq gene significantly decreased immunosuppression in chickens caused by pathogenic MDV.

Conclusion

These findings suggested that the Meq gene played an important role not only in tumour formation but also in inducing immunosuppressive effects in MDV-infected chickens, conclude Li and co-authors.

Reference

Li Y., A. Sun, S. Su, P. Zhao, Z. Cui and H. Zhu. 2011. Deletion of the Meq gene significantly decreases immunosuppression in chickens caused by pathogenic Marek's disease virus. Virology Journal, 8:2. doi:10.1186/1743-422X-8-2.