Attenuated <it>Salmonella</it> typhimurium delivering DNA vaccine encoding duck enteritis virus <it>UL24</it> induced systemic and mucosal immune responses and conferred good protection against challenge

• Main Authors: Yu Xia, Jia Renyong, Huang Juan, Shu Bin, Zhu Dekang, Liu Qing, Gao Xinghong, Lin Meng, Yin Zhongqiong, Wang Mingshu, Chen Shun, Wang Yin, Chen Xiaoyue, Cheng Anchun
• Format: Article
• Language: English
• Published: BMC 2012-07-01
• Series: Veterinary Research
• Online Access: http://www.veterinaryresearch.org/content/43/1/56
• ISSN: 0928-4249; 1297-9716

<p>Abstract</p> <p>Orally delivered DNA vaccines against duck enteritis virus (DEV) were developed using live attenuated <it>Salmonella</it> typhimurium (SL7207) as a carrier and <it>Escherichia coli</it> heat labile enterotoxin B subunit (LTB) as a mucosal adjuvant. DNA vaccine plasmids pVAX-UL24 and pVAX-LTB-UL24 were constructed and transformed into attenuated <it>Salmonella</it> typhimurium SL7207 resulting SL7207 (pVAX-UL24) and SL7207 (pVAX-LTB-UL24) respectively. After ducklings were orally inoculated with SL7207 (pVAX-UL24) or SL7207 (pVAX-LTB-UL24), the anti-DEV mucosal and systemic immune responses were recorded. To identify the optimum dose that confers maximum protection, we used different doses of the candidate vaccine SL7207 (pVAX-LTB-UL24) during oral immunization. The strongest mucosal and systemic immune responses developed in the SL7207 (pVAX-LTB-UL24) (10¹¹ CFU) immunized group. Accordingly, oral immunization of ducklings with SL7207 (pVAX-LTB-UL24) showed superior efficacy of protection (60-80%) against a lethal DEV challenge (1000 LD₅₀), compared with the limited survival rate (40%) of ducklings immunized with SL7207 (pVAX-UL24). Our study suggests that the SL7207 (pVAX-LTB-UL24) can be a candidate DEV vaccine.</p>