Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/31/2014
Publication Date: 7/11/2015
Citation: Fadly, A.M., Mays, J.K. 2015. Efficacy of a BAC clone of a recombinant strain of Marek’s disease virus containing reticuloendotheliosis virus LTR following in ovo Vaccination at 18 days of embryonation. Meeting Abstract. American Veterinary Medical Association Annual Convention, July 11-14, 2015, Boston, Massachusetts.
Technical Abstract: We have previously reported on the pathogenicity of various passage levels of a bacterial artificial chromosome (BAC) clone of a recombinant Marek’s disease virus (MDV) strain rMd5 containing reticuloendotheliosis virus (REV) long terminal repeat (LTR) termed rMd5 REV LTR BAC. In this study, we evaluated the protective efficacy of passage 70 of rMd5 REV LTR BAC following in ovo vaccination at 18 days of embryonation. Groups of maternal antibody positive (Mab+) and maternal antibody negative (Mab-) chickens of ADOL line 15I5 x 71 were each inoculated in ovo with 2000 pfu of rMd5 REV LTR BAC, or a commercial vaccine serotype 1 MDV vaccine, CVI988-Rispens. At 5 days of age, vaccinated and unvaccinated control chickens were challenged with 500 pfu of a vv+ MDV, strain 686. In ovo vaccination with the rMd5 REV LTR passage 70 BAC did not result in any atrophy of bursa or thymus, as evident by absence of gross and microscopic lesions. Although passage 70 of rMd5 REV LTR BAC protected chickens against MDV-induced bursa and thymic atrophy, the level of protection conferred by in ovo vaccination with the rMd5 REV LTR BAC was not as high as the level of protection conferred by the commercial vaccine, CVI988/Rispens.