Hamad Mustafa, Amen Omar, Mahmoud Mohamed, Hassanin Ola, Saif-Edin Mostafa
Poultry Diseases Department, Faculty of Veterinary Medicine, Assuit University, Zagazig, Egypt.
Avian and Rabbit Diseases Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.
Vet Res Commun. 2018 Jun;42(2):145-152. doi: 10.1007/s11259-018-9717-1. Epub 2018 Apr 4.
Avian influenza (AI) vaccines are widely used to control and eliminate the ongoing avian influenza virus epidemic in Egypt. A strict vaccination policy with inactivated AI vaccines has been widely applied, however the virus still circulating, evolving and causing great negative impact to the poultry sector in Egypt. Therefore, an updated poultry vaccination policy using different vaccine technologies might be valuable as an innovative additional control strategy of AIV in Egypt. In the present study, the effectiveness of different avian influenza (AI) vaccination schedules was evaluated in 300 commercial layer chicks (ISA White) using either the oil-emulsion baculovirus-H5-prototype vaccine (baculovirus-H5 prototype) or turkey herpesvirus (HVT) vector vaccine containing the hemagglutinin (HA) gene from H5N1 strain (rHVT-H5), applied alone or in combination and in different settings. Vaccination with either two injections of the baculovirus-H5 prototype, a single injection of rHVT-H5 or priming with rHVT-H5 at 1 day old followed by boosting with the baculovirus-H5 prototype induced AI-HI protective antibody responses starting as early as 3 to 4 weeks of age and lasting up to the end of the rearing period (16 weeks). A single vaccination with the baculovirus-H5 prototype did not generate a protective antibody titre for the entire rearing period. Furthermore, the present study elucidated that vaccination once or twice with the baculovirus-H5 vaccine prototype activated the chicken interferon-alpha (Ch-IFN-alpha) signalling pathway via transduction of antiviral components, e.g., Mx1 and IRF7. Birds immunized once with rHVT-H5 at 1 day old did not show activation of the Mx1 and IRF7 transcripts; however, following boosting with the baculovirus-H5 prototype vaccine, up-regulation of Mx1 and IRF7 was observed. Based on our findings, it can be concluded that either reinforcement with two injections of the baculovirus-H5 prototype or prime-boost vaccination (rHVT-H5 at 1 day old followed by the baculovirus-H5 prototype vaccine at 8 days old) is a successful strategy to induce both innate and humoral immune responses and could be recommended for the layer production sector over the entire rearing period, especially in AI-endemic areas.
禽流感（AI）疫苗被广泛用于控制和消除埃及当前的禽流感病毒疫情。灭活禽流感疫苗的严格接种政策已被广泛应用，然而病毒仍在传播、演变，并对埃及的家禽业造成巨大负面影响。因此，采用不同疫苗技术的更新后的家禽接种政策，作为埃及禽流感病毒创新的额外控制策略可能具有重要价值。在本研究中，使用油乳剂杆状病毒-H5-原型疫苗（杆状病毒-H5原型）或含有H5N1毒株血凝素（HA）基因的火鸡疱疹病毒（HVT）载体疫苗（rHVT-H5），单独或联合使用，并在不同情况下，对300只商品蛋鸡雏鸡（ISA白鸡）评估了不同禽流感（AI）接种方案的有效性。用两次注射杆状病毒-H5原型疫苗、单次注射rHVT-H5或在1日龄时用rHVT-H5进行初免，随后用杆状病毒-H5原型疫苗进行加强免疫，最早在3至4周龄时诱导禽流感血凝抑制（AI-HI）保护性抗体反应，并持续到饲养期结束（16周）。单次接种杆状病毒-H5原型疫苗在整个饲养期内未产生保护性抗体滴度。此外，本研究阐明，用杆状病毒-H5疫苗原型接种一次或两次，通过抗病毒成分（如Mx1和IRF7）的转导激活了鸡α干扰素（Ch-IFN-α）信号通路。在1日龄时用rHVT-H5免疫一次的鸡未显示Mx1和IRF7转录本的激活；然而，在用杆状病毒-H5原型疫苗加强免疫后，观察到Mx1和IRF7上调。根据我们的研究结果，可以得出结论，两次注射杆状病毒-H5原型疫苗进行强化免疫或初免-加强免疫（1日龄时用rHVT-H5，随后在8日龄时用杆状病毒-H5原型疫苗）是诱导先天性和体液免疫反应的成功策略，可推荐用于蛋鸡生产部门的整个饲养期，特别是在禽流感流行地区。
