Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: May 2, 2011
Publication Date: July 16, 2011
Citation: Lee, L.F., Heidari, M., Zhang, H., Reddy, S.M. 2011. Attenuation of Marek's disease virus lacking the Meq oncogene in cell culture [CD-ROM]. American Veterinary Medical Association (AVMA) Convention, July 16-19, 2011, St. Louis, Missouri. Paper No. 11067. Technical Abstract: Marek’s disease virus (MDV) encodes a basic leucine zipper oncoprotein, meq, which structurally resembles the jun/fos family of transcriptional activators. It has been clearly demonstrated that deletion of meq results in loss of transformation and oncogenic capacity of MDV. Chickens vaccinated with rMd5delta-meq virus provided superior protection over CVI988/Rispens when challenged with a very virulent plus (vv+) strain of MDV, 648A. Commercial chickens vaccinated with rMd5delta-meq and exposed to seeder birds inoculated with 686-MDV also showed rMd5delta- meq as an effective vaccine against Marek’s disease. Although deletion of Meq gene rendered the virus non-oncogenic, it still induces lymphoid organ atrophy like that of the parental virus, rMd5, in maternal antibody negative chickens. The cell culture attenuated rMd5delta meq virus has revealed mutations in the genome of this virus. The significance of this observation will be discussed.