Pan-African University for Life and Earth Sciences Institute, Ibadan, Nigeria.
Veterinary Teaching Hospital, College of Veterinary Medicine and Animal Sciences, University of Gondar, Gondar, Ethiopia.
J Immunol Res. 2022 Oct 15;2022:5392033. doi: 10.1155/2022/5392033. eCollection 2022.
Infectious bursal disease (IBD) is an immunosuppressive and economically important disease of young chickens caused by infectious bursal disease virus (IBDV). The National Veterinary Institute (Bishoftu, Ethiopia) produces intermediate IBDV vaccine using primary chicken embryo fibroblast (CEF) cells, a method with technical and economical cumbersome. This study assessed the safety, immunogenicity, and efficacy of DF-1 cell line-adapted IBDV LC-75 vaccine strain in reference to the CEF-based vaccine. Confluent monolayer of DF-1 cells was infected with IBDV and cells with cytopathic effects were passaged until 3 passage. Viral growth was confirmed using a one-step RT-PCR targeting IBDV VP2 gene. Viral titer increased from 1 passage through 3 passage. Safety was assessed in 30 specific-pathogen-free chickens (15 chickens/group) injected with 10-fold field dose of each vaccine intraocularly and monitored for 21 days. For immunogenicity and efficacy, 60 specific-pathogen-free chickens were grouped into 3 (20 chickens/group). First and 2 group received DF-1 cell and CEF-based IBDV vaccines, respectively. The 3 group served as unvaccinated control. Antibody response was measured using iELISA. Chickens were challenged 4 weeks postvaccination with very virulent IBDV (vvIBDV) intraocularly and followed-up for 10 days. Vaccination did not cause any adverse reactions during the 21 days of follow-up. In addition, both vaccines induced higher antibody titer 14 and 24 days-post-vaccination as compared to unvaccinated controls ( < 0.05). Moreover, DF-1 and CEF-based IBDV LC-75 vaccines rendered a complete protection against vvIBDV. Contrarily, morbidity and mortality in unvaccinated chickens was 50% and 30%, respectively. The results indicated that DF-1 and CEF cell-based IBDV vaccines are comparably immunogenic and efficacious. Therefore, DF-1 cell-line can be considered an affordable and convenient alternative to the CEF-based approach. The suitability of DF-1 cells to grow other IBDV strains and safety of these vaccines on bursa of Fabricius should further be investigated.
传染性法氏囊病（IBD）是一种由传染性法氏囊病病毒（IBDV）引起的、对幼鸡具有免疫抑制作用且具有重要经济意义的疾病。埃塞俄比亚比绍夫图的国家兽医研究所（National Veterinary Institute）使用原代鸡胚成纤维细胞（CEF）生产中间型 IBDV 疫苗，这种方法在技术和经济上都很繁琐。本研究评估了 DF-1 细胞系适应株 IBDV LC-75 疫苗株相对于 CEF 疫苗的安全性、免疫原性和功效。将长满单层的 DF-1 细胞用 IBDV 感染，出现细胞病变效应的细胞传代至第 3 代。使用针对 IBDV VP2 基因的一步 RT-PCR 确认病毒生长。病毒滴度从第 1 代到第 3 代逐渐增加。在 30 只无特定病原体鸡（每组 15 只鸡）中评估安全性，每只鸡眼内注射 10 倍田间剂量的每种疫苗，并监测 21 天。对于免疫原性和功效，将 60 只无特定病原体鸡分为 3 组（每组 20 只鸡）。第 1 组和第 2 组分别接受 DF-1 细胞和基于 CEF 的 IBDV 疫苗接种。第 3 组作为未接种疫苗的对照。使用 iELISA 测量抗体反应。在接种疫苗后 4 周，鸡用非常强毒力的 IBDV（vvIBDV）眼内攻毒，并进行为期 10 天的随访。在 21 天的随访期间，接种疫苗没有引起任何不良反应。此外，与未接种疫苗的对照组相比，两种疫苗在接种后 14 天和 24 天均诱导了更高的抗体滴度（<0.05）。此外，DF-1 和基于 CEF 的 IBDV LC-75 疫苗能完全抵抗 vvIBDV。相反，未接种疫苗的鸡的发病率和死亡率分别为 50%和 30%。结果表明，DF-1 和基于 CEF 的 IBDV 疫苗具有相当的免疫原性和功效。因此，DF-1 细胞系可以被视为 CEF 方法的一种经济实惠且便捷的替代方法。DF-1 细胞对其他 IBDV 株的适用性和这些疫苗对法氏囊的安全性应进一步研究。
