Université François Rabelais, INRA, UMR 0483 Université-INRA d'Immunologie Parasitaire, Vaccinologie et Biothérapie anti-infectieuse, IFR136 Agents Transmissibles et Infectiologie, UFR des Sciences Pharmaceutiques, 31 Avenue Monge, 37200 Tours, France.
Vaccine. 2011 Nov 8;29(48):8838-46. doi: 10.1016/j.vaccine.2011.09.099. Epub 2011 Oct 5.
The development of an effective vaccine against Toxoplasma gondii infection is an important issue due to the seriousness of the related public health problems, and the economic importance of this parasitic disease worldwide. Rhoptry neck proteins (RONs) are components of the moving junction macromolecular complex formed during invasion. The aim of this study was to evaluate the vaccine potential of RON4 using two vaccination strategies: DNA vaccination by the intramuscular route, and recombinant protein vaccination by the nasal route. We produced recombinant RON4 protein (RON4S2) using the Schneider insect cells expression system, and validated its antigenicity and immunogenicity. We also constructed optimized plasmids encoding full length RON4 (pRON4), or only the N-terminal (pNRON4), or the C-terminal part (pCRON4) of RON4. CBA/J mice immunized with pRON4, pNRON4 or pCRON4 plus a plasmid encoding the granulocyte-macrophage-colony-stimulating factor showed high IgG titers against rRON4S2. Mice immunized by the nasal route with rRON4S2 plus cholera toxin exhibited low levels of anti-RON4S2 IgG antibodies, and no intestinal IgA antibodies specific to RON4 were detected. Both DNA and protein vaccination generated a mixed Th1/Th2 response polarized towards the IgG1 antibody isotype. Both DNA and protein vaccination primed CD4+ T cells in vivo. In addition to the production of IFN-γ, and IL-2, Il-10 and IL-5 were also produced by the spleen cells of the immunized mice stimulated with RON4S2, suggesting that a mixed Th1/Th2 type immune response occurred in all the immunized groups. No cytokine was detectable in stimulated mesenteric lymph nodes from mice immunized by the nasal route. Immune responses were induced by both DNA and protein vaccination, but failed to protect the mice against a subsequent oral challenge with T. gondii cysts. In conclusion, strategies designed to enhance the immunogenicity and to redirect the cellular response towards a Th1 type response against RON4 could lead to more encouraging results.
弓形虫感染的有效疫苗的开发是一个重要的问题，因为相关的公共卫生问题的严重性，以及这种寄生虫病在全球范围内的经济重要性。棒状体颈蛋白（RONs）是在侵袭过程中形成的运动连接大分子复合物的组成部分。本研究的目的是评估 RON4 用两种疫苗接种策略的疫苗潜力：肌肉内途径的 DNA 疫苗接种，和鼻腔途径的重组蛋白疫苗接种。我们使用 Schneider 昆虫细胞表达系统生产重组 RON4 蛋白（RON4S2），并验证其抗原性和免疫原性。我们还构建了编码全长 RON4 的优化质粒（pRON4），或仅 RON4 的 N 端（pNRON4）或 C 端部分（pCRON4）。用 pRON4、pNRON4 或 pCRON4 加编码粒细胞-巨噬细胞集落刺激因子的质粒免疫 CBA/J 小鼠后，针对 rRON4S2 的 IgG 滴度很高。用 rRON4S2 加霍乱毒素经鼻腔免疫的小鼠显示出针对 RON4S2 的低水平 IgG 抗体，并且未检测到针对 RON4 的肠道 IgA 抗体。DNA 和蛋白质疫苗接种均产生向 IgG1 抗体同种型极化的混合 Th1/Th2 反应。DNA 和蛋白质疫苗接种均在体内引发 CD4+T 细胞。除了产生 IFN-γ和 IL-2 外，用 RON4S2 刺激免疫小鼠的脾细胞还产生了 IL-10 和 IL-5，这表明所有免疫组均发生了混合 Th1/Th2 型免疫反应。用鼻腔途径免疫的小鼠的肠系膜淋巴结中未检测到细胞因子。DNA 和蛋白质疫苗接种均诱导免疫反应，但未能保护小鼠免受随后口服弓形虫包囊的攻击。总之，旨在增强免疫原性并将细胞反应重定向为针对 RON4 的 Th1 型反应的策略可能会产生更令人鼓舞的结果。
