Canine parvovirus type 2 (CPV2) is a highly contagious cause of serious and often fatal disease in young dogs. Despite the widespread availability of attenuated vaccines, safer, more stable, and more effective CPV2 vaccine candidates are still under exploration. Vaccinia virus (VV) has already been proved to be a safe, stable, and effective vaccine vector. In this study, we generated a VV-based CPV2 vaccine candidate (VV_-CPV-VP2) and then evaluated its immunogenicity in mice and dogs. The exogenous vp2 gene of CPV2, which replaced the major virulence gene hemagglutinin (ha) of VV, expressed efficiently and stably in vitro. Subsequently, intramuscular immunization of mice induced robust and lasting systemic immune responses, including neutralizing antibody against both CPV2a and CPV2b, and CPV2-VP2-specific interferon gamma (IFN-γ) secreting T cell. In addition, administration with a high-dose of VV_-CPV-VP2 did not cause significant side effects for mice, thus indicating marked safety of this vaccine candidate. Most importantly, a single-dose vaccination of VV_-CPV2-VP2 elicited substantial antibody responses and provided comparable protection for dogs with attenuated CPV2 vaccine. Collectively, this study demonstrated that VV_-CPV2-VP2 could be used as a promising vaccine candidate preventing CPV2 from infection for dogs.

中文翻译：

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用编码犬细小病毒2 vp2的牛痘病毒进行管理可引起小鼠和犬的全身免疫反应。

2型犬细小病毒（CPV2）是引起幼犬严重且经常致命的严重传染病的原因。尽管减毒疫苗广泛可用，但仍在探索更安全，更稳定和更有效的CPV2候选疫苗。牛痘病毒（VV）已被证明是一种安全，稳定和有效的疫苗载体。在这项研究中，我们生成了基于VV的CPV2候选疫苗（VV _-CPV-VP2），然后评估了其在小鼠和狗中的免疫原性。CPV2的外源vp2基因取代了VV的主要毒力基因血凝素（ha），可在体外高效稳定表达。随后，将小鼠的肌肉内免疫诱导健壮和持久的全身性免疫应答，包括中和抗体对两种CPV2a和CPV2b，和VP2特异性CPV2干扰素γ（IFN- γ）分泌型T细胞。另外，大剂量的VV _-CPV-VP2给药对小鼠没有明显的副作用，因此表明该候选疫苗具有明显的安全性。最重要的是，VV _-CPV2-VP2的单剂量疫苗接种引起了实质性抗体反应，并为带有减毒CPV2疫苗的狗提供了可比的保护。总体而言，这项研究表明，VV _-CPV2-VP2可以用作预防CPV2感染狗的有前途的候选疫苗。