PDF(Pubmed)
Abstract：
Riemerella anatipestifer (RA) causes epizootic infectious polyserositis in ducks with high mortality and leads to huge economic losses worldwide. Bacterial resistance poses a challenge for the control of the disease, vaccines failed to provide ideal cross-protection. Thus, the preparation of vaccines based on popular serotypes is important. In this study, we collected 700 brain and liver tissues of dead ducks from 8 provinces in southern China from 2016 to 2022 and obtained 195 RA isolates with serotypes 1, 2, 7, and 10. Serotypes 1 and 2 were the most prevalent (82%). A novel bivalent inactivated vaccine WZX-XT5 containing propolis adjuvant was prepared, we chose XT5 (serotype 1) and WZX (serotype 2) as vaccine strains and evaluated WZX-XT5-induced immune response and protective efficacy in ducks. Results showed that the XT5 (LD50, 3.5 × 103 CFU) exhibited high virulence and provided better protection against RA compared with ZXP, DCR and LCF1 (LD50, 108 CFU). Notably, the dose of 109 CFU provided ideal protection compared with 108 CFU, propolis and oil emulsion adjuvants induced stronger protective efficacy compared with aluminum hydroxide adjuvant. Importantly, WZX-XT5 immunization induced high levels of RA-specific IgY, IFN-γ, IL-2, and IL-4 in serum and offered over 90% protection against RA with ultra-high lethal dose in ducks. Additionally, no clinical signs of RA infection or obvious pathological damage in tissues were observed in protected ducks. Overall, this study first reports the identification, serotyping and virulence of RA in ducks of southern China and the preparation of a novel bivalent inactivated vaccine, providing useful scientific information to prevent and control RA infection.
摘要：
鼠疫Riemerella（RA）在鸭中引起高死亡率的流行病传染性多发性浆膜炎，并在全球范围内造成巨大的经济损失。细菌耐药性对疾病的控制提出了挑战,疫苗未能提供理想的交叉保护。因此，基于流行血清型的疫苗制备很重要。在这项研究中,我们从2016年至2022年收集了中国南方8个省份的死鸭的700例脑和肝脏组织,获得了195个RA分离株,血清型为1,2,7和10.血清型1和2是最普遍的(82%)。制备了含蜂胶佐剂的新型二价灭活疫苗WZX-XT5,我们选择XT5（血清型1）和WZX（血清型2）作为疫苗株，并评估了WZX-XT5在鸭中诱导的免疫应答和保护效果。结果表明，与ZXP相比，XT5（LD50，3.5×103CFU）具有较高的毒力，对RA具有更好的保护作用。DCR和LCF1（LD50，108CFU）。值得注意的是,与108CFU相比，109CFU的剂量提供了理想的保护，与氢氧化铝佐剂相比，蜂胶和油乳剂佐剂具有更强的保护作用。重要的是,WZX-XT5免疫诱导高水平的RA特异性IgY，IFN-γ，血清中的IL-2和IL-4，在鸭子中具有超高致死剂量，对RA具有90％以上的保护作用。此外,在受保护的鸭中未观察到RA感染的临床迹象或组织中明显的病理损伤。总的来说,这项研究首先报告了鉴定，中国南方鸭RA的血清分型和毒力鉴定以及新型二价灭活疫苗的制备，为预防和控制RA感染提供有用的科学信息。
