Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Beijing Zhongnong Bioengineering Co., Ltd., Beijing 100193, China.
Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China; Beijing Zhongnong Bioengineering Co., Ltd., Beijing 100193, China.
Poult Sci. 2020 Dec;99(12):6454-6461. doi: 10.1016/j.psj.2020.08.022. Epub 2020 Aug 28.
Currently, the widely used vaccine against duck Tembusu virus (DTMUV) disease is inactivated vaccine which, however, facing the limits of large inoculation dose, short immunization period, and incomplete effectiveness. Access to efficient adjuvants aiding for DTMUV inactivated vaccine seems to be of critical importance. Interleukin-2 (IL-2) was reported to induce a persistent expansion of effector T cells and could be a promising molecular adjuvant for many kinds of vaccines. In this study, the efficacy of duck interleukin (dIL)-2 as an adjuvant for a DTMUV inactivated vaccine was evaluated. Fifty-five Pekin ducks were divided into 5 groups and intramuscularly administered with 5 batches of vaccines at 42 D (A: DTUMV + dIL-2; B: 1/2DTUMV + dIL-2; C: DTUMV; D: 1/2DTUMV and E: PBS), respectively, and received the second vaccination 2 wk later. Fifty-six days after immunization, 6 ducks from each group were randomly selected to conduct a challenge protection test. Antibody titers and cytokine responses were detected to assess humoral and cellular immune responses in serum of inoculated ducks by hemagglutination inhibition and ELISA, respectively; virus isolation and RT-PCR method were used in immunity protective test. Our results showed that dIL-2 exerted an enhanced effect on the vaccine while reducing the dose of inoculated antigen highlighting high adjuvanticity of IL-2. The vaccines supplemented with IL-2 induced a higher level of antibodies and higher percentage of inhibition values than inactivated vaccines without IL-2 to a significant extent. The production level of IFN-α, IFN-γ, and IL-6 genes were elevated, enhancing both humoral and cellular responses. Furthermore, it provided higher protection after virus challenge. Therefore, IL-2 can be considered as a potential adjuvant for inactivated vaccine against DTMUV disease.
目前，广泛使用的鸭坦布苏病毒（DTMUV）病疫苗是灭活疫苗，但面临着接种剂量大、免疫期短、效果不完全的限制。获得有效的佐剂来辅助 DTMUV 灭活疫苗似乎至关重要。白细胞介素-2（IL-2）被报道能诱导效应 T 细胞的持续扩增，是许多疫苗的有前途的分子佐剂。本研究评估了鸭白细胞介素（dIL）-2作为 DTMUV 灭活疫苗佐剂的功效。55 只北京鸭分为 5 组，分别在 42 日龄（A：DTUMV+dIL-2；B：1/2DTUMV+dIL-2；C：DTUMV；D：1/2DTUMV 和 E：PBS）肌肉内接种 5 批疫苗，两周后进行第二次接种。免疫后 56 天，每组随机选择 6 只鸭子进行攻毒保护试验。通过血凝抑制试验和 ELISA 分别检测血清中的抗体滴度和细胞因子反应，评估接种鸭的体液和细胞免疫反应；通过病毒分离和 RT-PCR 方法进行免疫保护试验。结果表明，dIL-2 增强了疫苗的作用，同时减少了接种抗原的剂量，突出了 IL-2 的高佐剂活性。与不含 IL-2 的灭活疫苗相比，补充 IL-2 的疫苗诱导的抗体水平更高，抑制值百分比更高，差异有统计学意义。IFN-α、IFN-γ和 IL-6 基因的产生水平升高，增强了体液和细胞反应。此外，它在病毒攻毒后提供了更高的保护。因此，IL-2 可以被认为是 DTMUV 病灭活疫苗的一种潜在佐剂。
