Vaccination of mice with recombinant NcROP2 antigen reduces mortality and cerebral infection in mice infected with Neospora caninum tachyzoites
Vaccination of mice with recombinant NcROP2 antigen reduces mortality and cerebral infection in mice infected with Neospora caninum tachyzoites
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DOI：
10.1016/j.ijpara.2008.04.001
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发表时间：
2008-10-01
影响因子：
4
通讯作者：
Hemphill, Andrew
中科院分区：
文献类型：
--
作者：
Debache, Karim;Guionaud, Christophe;Hemphill, Andrew
棒状体抗原参与多种与宿主细胞入侵、寄生虫空泡形成和寄生虫-宿主细胞相互作用相关的细胞功能。从犬新孢子虫表达序列标签（ESTs）中鉴定这些抗原之一NcROP 2的cDNA序列，通过逆转录-PCR扩增，在大肠杆菌中表达为（HiS）（6）-标记的重组蛋白（recNcROP 2），并通过Ni 2 +-亲和层析纯化。recNcROP 2和针对recNcROP 2的抗体对N.犬速殖子体外侵入宿主细胞，表明该蛋白参与宿主细胞进入过程。随后，在C57 BL/6小鼠脑疾病模型中评估NcROP 2作为潜在疫苗候选物的保护功效。以2周间隔用在弗氏不完全佐剂（FIA）或皂苷中乳化的recNcROP 2对小鼠接种三次，并且对照组用单独的佐剂（佐剂对照）或PBS（感染对照）处理。随后，用2 × 10（6）N对小鼠进行攻击。犬速殖子全部属于感染对照组或佐剂对照组的9只小鼠表现出脑新孢子虫病的临床体征并死于感染，而recNcROP 2疫苗接种的小鼠没有观察到临床体征。对于所有其他动物，实验在感染后35天终止。在所有小鼠中通过定量PCR评估脑寄生虫负荷，并且显示在recNcROP 2疫苗接种的小鼠中显著降低。血清的ELISA显示IgGl在recNcROP 2-皂苷接种的小鼠中升高，而IgG 2a在recNcROP 2-FIA接种的动物中更高。这表明，根据使用的佐剂，用NcROP 2接种诱导针对实验性N.犬感染(C)2008年澳大利亚寄生虫学会由爱思唯尔有限公司出版。保留所有权利。
Rhoptry antigens are involved in a variety of cellular functions related to host cell invasion, formation of the parasitophorous vacuole and parasite-host cell interplay. The cDNA sequence of one of these antigens, NcROP2 was identified from Neospora caninum expressed sequence tags (ESTs), amplified by reverse transcription-PCR, expressed in Escherichia coli as a (HiS)(6)-tagged recombinant protein (recNcROP2) and purified over Ni2+-affinity chromatography. Both recNcROP2 and antibodies directed against recNcROP2 had a negative impact on N. caninum tachyzoitc host cell invasion in vitro, indicating that this protein participates in the host cell entry process. Subsequently, the protective efficacy of NcROP2 as a potential vaccine candidate was evaluated in a C57BL/6 mouse cerebral disease model. Mice were vaccinated three times at 2-week intervals with recNcROP2 emulsified either in Freund's incomplete adjuvants (FIA) or saponin, and control groups were treated with adjuvants alone (adjuvants control) or PBS (infection control). Subsequently, mice were challenged with 2 x 10(6) N. caninum tachyzoites. Nine mice, all belonging to the infection control or adjuvants control groups, exhibited clinical signs of cerebral neosporosis and succumbed to infection, whilst no clinical signs were noted for recNcROP2-vaccinated mice. For all other animals, the experiment was terminated 35 days p.i. Cerebral parasite burdens were assessed by quantitative PCR in all mice, and were revealed to be significantly reduced in the recNcROP2-vaccinated mice. ELISA of sera revealed IgG1 to be elevated in recNcROP2-saponin vaccinated mice, whilst IgG2a was higher in recNcROP2-FIA vaccinated animals. This shows that, depending on the adjuvants used, vaccination with NcROP2 induces a protective Th-1- or Th-2-biased immune response against experimental N. caninum infection. (C) 2008 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.