Dawe W H, Kapczynski D R, Linnemann E G, Gauthiersloan V R, Sellers H S
Poultry Diagnostic and Research Center, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
U.S. National Poultry Research Center, Agricultural Research Services, U.S. Department of Agriculture, Athens, GA 30605.
Avian Dis. 2022 Dec;66(4):465-478. doi: 10.1637/aviandiseases-D-22-99992.
Avian orthoreoviruses are causative agents of tenosynovitis and viral arthritis in both chickens and turkeys. Current commercial reovirus vaccines do not protect against disease caused by emerging variants. Custom-made inactivated reovirus vaccines are commonly utilized to help protect commercial poultry against disease. Antibody epitopes located on the viral attachment protein, σC, involved in virus neutralization, have not been clearly identified. In this study, the S1133 vaccine strain (Genetic Cluster 1 [GC1], a GC1 field isolate (117816), and a GC5 field isolate (94826) were determined to be genetically and serologically unrelated. In addition, chickens were vaccinated with either a commercial S1133 vaccine, 117816 GC1, or 94826 GC5, and sera were used in peptide microarrays to identify linear B-cell epitopes within the σC protein. Specific-pathogen-free (SPF) chickens were vaccinated twice with either: 1) live and live, 2) inactivated and inactivated, or 3) a combination of live and inactivated vaccines. Epitope mapping was performed on individual serum samples from birds in each group using S1133, 117816, and 94826 σC sequences translated into an overlapping peptides and spotted onto microarray chips. Vaccination with a combination of live and inactivated viruses resulted in a greater number of B-cell binding sites on the outer-capsid domains of σC for 117816 and 94826, but not for S1133. In contrast, the S1133-vaccinated birds demonstrated fewer epitopes, and those epitopes were located in the stalk region of the protein. However, within each of the vaccinated groups, the highest virus-neutralization titers were observed in the live/inactivated groups. This study demonstrates differences in antibody binding sites within σC between genetically and antigenically distinct reoviruses and provides initial antigenic characterization of avian orthoreoviruses and insight into the inability of vaccine-induced antibodies to provide adequate protection against variant reovirus-induced disease.
禽正呼肠孤病毒是鸡和火鸡腱鞘炎和病毒性关节炎的病原体。目前的商业呼肠孤病毒疫苗不能预防由新出现的变异株引起的疾病。定制的灭活呼肠孤病毒疫苗通常用于帮助保护商业家禽免受疾病侵害。位于病毒附着蛋白σC上参与病毒中和的抗体表位尚未明确鉴定。在本研究中，确定S1133疫苗株（遗传簇1 [GC1]）、一株GC1田间分离株（117816）和一株GC5田间分离株（94826）在遗传和血清学上不相关。此外，用商业S1133疫苗、117816 GC1或94826 GC5对鸡进行免疫接种，并将血清用于肽微阵列，以鉴定σC蛋白内的线性B细胞表位。无特定病原体（SPF）鸡用以下方式免疫接种两次：1）活疫苗和活疫苗，2）灭活疫苗和灭活疫苗，或3）活疫苗和灭活疫苗的组合。使用翻译成重叠肽并点样到微阵列芯片上的S1133、117816和94826 σC序列，对每组鸡的个体血清样本进行表位作图。用活病毒和灭活病毒组合进行免疫接种，导致117816和94826的σC外衣壳结构域上有更多的B细胞结合位点，但S1133没有。相比之下，接种S1133疫苗的鸡显示出较少的表位，且这些表位位于该蛋白的柄部区域。然而，在每个免疫接种组中，活疫苗/灭活疫苗组观察到最高的病毒中和滴度。本研究证明了遗传和抗原性不同的呼肠孤病毒之间σC内抗体结合位点的差异，并提供了禽正呼肠孤病毒的初步抗原特征，以及对疫苗诱导的抗体无法为变异呼肠孤病毒引起的疾病提供充分保护的深入了解。
