Abstract

Pasteurella multocida is the main cause of haemorrhagic septicaemia (HS) outbreak in livestock, such as cattle and buffaloes. Conventional vaccines such as alum-precipitated or oil-adjuvant broth bacterins were injected subcutaneously to provide protection against HS. However, the immunity developed is only for short term and needed to be administered frequently. In our previous study, a short gene fragment from Pasteurella multocida serotype B was obtained via shotgun cloning technique and later was cloned into bacterial expression system. pQE32-ABA392 was found to possess immunogenic activity towards HS when tested in vivo in rat model. In this study, the targeted gene fragment of ABA392 was sub-cloned into a DNA expression vector pVAX1 and named as pVAX1-ABA392. The new recombinant vaccine was stable and expressed on mammalian cell lines. Serum sample collected from a group of vaccinated rats for ELISA test shows that the antibody in immunized rats was present at high titer and can be tested as a vaccine candidate with challenge in further studies. This successful recombinant vaccine is immunogenic and potentially could be used as vaccine in future against HS.

中文翻译：

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出血性败血症的潜在DNA疫苗

摘要

多杀性巴氏杆菌是牲畜（例如牛和水牛）中出血性败血病（HS）暴发的主要原因。皮下注射常规疫苗，例如明矾沉淀或油佐剂肉汤菌苗，以提供抗HS的保护。但是，所产生的免疫力仅是短期的，需要经常给予。在我们之前的研究中，多杀巴斯德氏菌的短基因片段通过shot弹枪克隆技术获得血清型B，然后将其克隆到细菌表达系统中。当在大鼠模型中体内测试时，发现pQE32-ABA392具有针对HS的免疫原性活性。在这项研究中，将ABA392的靶向基因片段亚克隆到DNA表达载体pVAX1中，并命名为pVAX1-ABA392。新的重组疫苗稳定并在哺乳动物细胞系中表达。从一组接种疫苗的大鼠中收集的血清样品用于ELISA测试，结果显示免疫大鼠中的抗体滴度高，可以作为有挑战的疫苗候选物进行进一步研究。这种成功的重组疫苗具有免疫原性，将来有可能用作抗HS的疫苗。