Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5537007 | Vaccine | 2017 | 7 Pages |
Abstract
Gallid herpesvirus 2 (GaHV-2) continuously evolves, which reduces the effectiveness of existing vaccines. To construct new GaHV-2 candidate vaccines, LMS, which is a virulent GaHV-2 field strain isolated from diseased chicken flocks in Southwest China in 2007, was modified such that both copies of its meq oncogene were partially deleted. The resulting virus, i.e., rMSÎmeq, was characterized using PCR and sequencing. To evaluate the safety and protective efficacy of rMSÎmeq, specific pathogen-free (SPF) chickens were inoculated with 2000 plaque forming units (pfu) and 20,000Â pfu of rMSÎmeq immediately after hatching. All birds grew well during the experimental period, and none of the challenged chickens developed Marek's disease-associated lymphoma. In addition, the rMSÎmeq- and CVI988/Rispens-vaccinated SPF chickens were challenged with 1000 pfu and 5000 pfu of the representative virulent GaHV-2 Md5 strain and 1000 pfu of the variant GaHV-2 strains LCC or LTS. The results showed that the rMSÎmeq strain provided complete protection, which was similar to that provided by the CVI988/Rispens vaccine (protective index (PI) of 95.5) when challenged with a conventional dose of the Md5 strain. However, rMSÎmeq provided a PI of 90.9 when challenged with 5000 pfu of the Md5 strain, which was significantly higher than that provided by the CVI988/Rispens vaccine (54.5). rMSÎmeq provided a PI of 86.4 against LCC, which was equal to that provided by the CVI988/Rispens vaccine (81.8). In addition, rMSÎmeq provided a PI of 100 against LTS, which was significantly higher than that provided by the CVI988/Rispens vaccine (68.2). Altogether, the rMSÎmeq virus provided efficient protection against representative and variant GaHV-2 strains. In conclusion, the rMSÎmeq virus is a safe and effective vaccine candidate for the prevention of Marek's disease and is effective against the Chinese variant GaHV-2 strains.
Related Topics
Life Sciences
Immunology and Microbiology
Immunology
Authors
Yanping Zhang, Changjun Liu, Fuhai Yan, Ailing Liu, Yun Cheng, Zhijie Li, Guorong Sun, Hongchao Lv, Xiaomei Wang,