Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek's disease virus containing a reticuloendotheliosis virus long terminal repeat.

Protective efficacy of a recombinant bacterial artificial chromosome clone of a very virulent Marek's disease virus containing a reticuloendotheliosis virus long terminal repeat. Avian Pathol. 2016 Dec;45(6):657-666 Authors: Mays JK, Black-Pyrkosz A, Spatz S, Fadly AM, Dunn JR Abstract Marek's disease virus (MDV), an alphaherpesvirus, causes Marek's disease (MD), a lymphoproliferative disease in poultry characterized by T-cell lymphomas, nerve lesions, and mortality. Vaccination is used worldwide to control MD, but increasingly virulent field strains can overcome this protection, driving a need to create new vaccines. Previous studies revealed that insertion of reticuloendotheliosis virus (REV) long terminal repeat (LTR) into a bacterial artificial chromosome (BAC) clone of a very virulent strain of MDV, Md5, rendered the resultant recombinant virus, rMd5 REV-LTR BAC, fully attenuated in maternal antibody positive (Mab+) chickens at passage 40. In the current study, the protective efficacy of rMd5 REV-LTR BAC was evaluated. First, passage 70 was identified as being fully attenuated in maternal antibody negative chickens and chosen as the optimal passage level for use in protective efficacy studies. Second, three protective efficacy trials were conducted comparing the rMd5 REV-LTR p70 BAC to the CVI988/Rispens vaccine. Groups of Mab+ and Mab- 15I5 × 71 chickens were vaccinated in ovo at 18 days of embryonation or intra-abdominall...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research