Shao Guanming, Fu Jun, Pan Yun, Gong Shiying, Song Chaoyi, Chen Sheng, Feng Keyu, Zhang Xinheng, Xie Qingmei
State Key Laboratory of Swine and Poultry Breeding Industry & Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China; Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China; Guangdong Engineering Research Center for Vector Vaccine of Animal Virus, Guangzhou 510642, PR China; Zhongshan Innovation Center of South China Agricultural University, Zhongshan 528400, PR China.
State Key Laboratory of Microbial Technology, Helmholtz International Lab for Anti-Infectives, Institute of Microbial Technology, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, PR China.
Poult Sci. 2025 Jan;104(1):104578. doi: 10.1016/j.psj.2024.104578. Epub 2024 Nov 22.
Infectious laryngotracheitis (ILT) is a highly contagious disease, usually controlled by vaccination with live attenuated vaccines. However, the latent infection and adverse reactions caused by the live attenuated vaccines against infectious laryngotracheitis virus (ILTV) have limited its use in poultry. Infectious bronchitis virus (IBV) is considered a potential vector for vaccine development, but the issue of poor stability in recombinant IBV expressing foreign genes has not yet been resolved. In this study, we designed a multi-epitope cassette (gD-T/B) containing multiple T and B cell epitopes of ILTV gD protein. The genetic stability of the full-length gD gene and the gD-T/B multi-epitope cassette replacing non-essential genes in IBV was systematically analyzed. We found that, at the same insertion site, the stability of inserting gD-T/B multi-epitope cassette was consistently higher compared to the full-length gD gene. This difference may be related to the presence of more signals affecting virus replication or transcription in larger heterologous genes. In addition, the stability of recombinant IBV varied depending on the genome region being replaced. When the gene 5 was replaced, rH120-Δ5ab-gD-T/B was maintained up to at least passage 20 (P20). Compared with the parental virus H120 strain, rH120-Δ5ab-gD-T/B showed similar growth kinetics. Clinical observations and scoring of clinical signs in the vaccination-challenge experiment showed that rH120-Δ5ab-gD-T/B provided 90% protection against virulent ILTV, effectively alleviating clinical signs caused by infection with a virulent strain of ILTV. Furthermore, rH120-Δ5ab-gD-T/B significantly reduced the replication and shedding of ILTV in the trachea. Overall, this study suggests that rH120-Δ5ab-gD-T/B is a promising candidate vaccine against ILTV.
传染性喉气管炎（ILT）是一种高度传染性疾病，通常通过接种减毒活疫苗来控制。然而，针对传染性喉气管炎病毒（ILTV）的减毒活疫苗所引起的潜伏感染和不良反应限制了其在家禽中的应用。传染性支气管炎病毒（IBV）被认为是疫苗开发的潜在载体，但在表达外源基因的重组IBV中稳定性差的问题尚未得到解决。在本研究中，我们设计了一个包含ILTV gD蛋白多个T细胞和B细胞表位的多表位盒（gD-T/B）。系统分析了全长gD基因和取代IBV非必需基因的gD-T/B多表位盒的遗传稳定性。我们发现，在相同的插入位点，与全长gD基因相比，插入gD-T/B多表位盒的稳定性始终更高。这种差异可能与较大的异源基因中存在更多影响病毒复制或转录的信号有关。此外，重组IBV的稳定性因被取代的基因组区域而异。当基因5被取代时，rH120-Δ5ab-gD-T/B至少能维持传代20次（P20）。与亲本病毒H120株相比，rH120-Δ5ab-gD-T/B表现出相似的生长动力学。疫苗接种-攻毒实验中的临床观察和临床症状评分表明，rH120-Δ5ab-gD-T/B对强毒ILTV提供了90%的保护，有效减轻了强毒ILTV感染引起的临床症状。此外，rH120-Δ5ab-gD-T/B显著降低了ILTV在气管中的复制和脱落。总体而言，本研究表明rH120-Δ5ab-gD-T/B是一种有前景的抗ILTV候选疫苗。
