Pradhan Satya Narayan, Prince Prabhu Rajaiah, Madhumathi Jayaprakasam, Roy Parimal, Narayanan Rangarajan Badri, Antony Usha
Centre for Biotechnology, Anna University, Chennai 600025, India.
Vet Immunol Immunopathol. 2012 Aug 15;148(3-4):293-301. doi: 10.1016/j.vetimm.2012.06.019. Epub 2012 Jun 23.
Infectious bursal disease virus (IBDV) is the causative agent of Gumboro disease and poses a huge threat to poultry industry. The risks associated with conventional attenuated viral vaccines make it indispensable to probe into the development of novel and rationally designed subunit vaccines which are safer as well as effective. VP2 is the major host-protective antigen found in IBDV capsid. It encompasses different independent epitopes responsible for the induction of neutralizing antibody. Here, we report the efficacy of the immunodominant fragment of VP2 which induces both humoral and cellular immunity against infectious bursal disease. A 366 bp fragment (52-417 bp) of the VP2 gene from an IBDV field isolate was amplified and expressed in Escherichia coli as a 21 kDa recombinant protein. The efficacy of rVP2(52-417) antigen was compared with two commercial IBDV whole virus vaccine strains. The rVP2(52-417) induced significantly high antibody titres in chicken compared to commercial vaccines and the anti-rVP2(52-417) sera showed reactivity with viral antigens from both commercial strains (P<0.0001) and field isolates. Also, the chicken splenocytes from rVP2(52-417) immunized group showed a significantly high proliferation (P<0.01) compared to other groups, which implies that the rVP2(52-417) fragment contains immunogenic epitopes capable of eliciting both B and T cell responses. Further, rVP2(52-417) conferred 100% protection against vIBDV challenge in the immunized chickens which was significantly higher (P<0.001) compared to 55-60% protection by commercial vaccine strains. Hence, the study confirms the efficacy of the immunodominant VP2 fragment that could be used as a potent vaccine against IBDV infection in chicken.
传染性法氏囊病病毒（IBDV）是甘博罗病的病原体，对家禽业构成巨大威胁。传统减毒活疫苗存在的风险使得研发新型且合理设计的亚单位疫苗成为必然，这种疫苗更安全且有效。VP2是在IBDV衣壳中发现的主要宿主保护性抗原。它包含不同的独立表位，负责诱导中和抗体。在此，我们报告了VP2免疫显性片段诱导针对传染性法氏囊病的体液免疫和细胞免疫的功效。从一株IBDV野外分离株中扩增出VP2基因的一个366 bp片段（52 - 417 bp），并在大肠杆菌中表达为一种21 kDa的重组蛋白。将重组VP2（52 - 417）抗原的功效与两种市售IBDV全病毒疫苗株进行了比较。与市售疫苗相比，重组VP2（52 - 417）在鸡中诱导出显著更高的抗体滴度，并且抗重组VP2（52 - 417）血清与来自两种市售毒株（P < 0.0001）和野外分离株的病毒抗原均有反应。此外，与其他组相比，重组VP2（52 - 417）免疫组的鸡脾细胞显示出显著更高的增殖（P < 0.01），这意味着重组VP2（52 - 417）片段包含能够引发B细胞和T细胞反应的免疫原性表位。进一步的研究表明，重组VP2（52 - 417）在免疫鸡中对超强毒IBDV攻击提供了100%的保护，与市售疫苗株55 - 60%的保护率相比显著更高（P < 0.001）。因此，该研究证实了免疫显性VP2片段的功效，其可作为预防鸡IBDV感染的有效疫苗。
