National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan; Department of Animal Medicine, Faculty of Veterinary Medicine, South Valley University, Qena City, Qena 83523, Egypt.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Vaccine. 2019 Feb 8;37(7):937-944. doi: 10.1016/j.vaccine.2019.01.005. Epub 2019 Jan 16.
Neospora caninum is an intracellular protozoan parasite closely related to Toxoplasma gondii. N. caninum is thought to be a major cause of abortion in cattle worldwide. Given the current situation of drastic economic losses and a lack of efficient control strategies against such parasites, the challenge to develop potent vaccine candidates and technologies remains. We investigated the immune stimulating activity of N. caninum cyclophilin (NcCyp) with and without a formulation with oligomannose-coated-liposomes (OML) as the potential adjuvant. NcCyp-OML activated NF-κB in RAW 264.7 cells and triggered interleukin (IL)-12p40 production from murine peritoneal macrophages. In BALB/c mice, immunization with NcCyp-OML was associated with the production of specific antibodies (IgG1 and IgG2a). The specific antibody (IgG1) against naked NcCyp was also observed after the challenge infection, but it was significantly lower than those of NcCyp-OML. Moreover, significant cellular immune responses were induced, including spleen cell proliferation and interferon-gamma production. The immunization of mice with NcCyp-OML, and to lesser extent with naked NcCyp, induced significant protection against challenge with a lethal dose of N. caninum compared with the PBS control group. This protection was associated with a higher survival rate, slight changes in body weight, and lower clinical score of mice. In addition, the significant protective efficacy of NcCyp-OML was confirmed in another mouse strain, male C57BL/6 mice. The current study revealed the marked contribution of Toll-like receptor 2 (TLR2) to the protective immunity triggered by NcCyp-OML because higher numbers of TLR2 mice succumbed to a lethal dose of N. caninum compared with C57BL/6 mice. Moreover, prominent spleen cell proliferation and IFN-γ production was induced in NcCyp-OML-immunized mice by a TLR2-dependent mechanism.
刚地弓形虫是一种与弓形虫密切相关的细胞内原生动物寄生虫。刚地弓形虫被认为是全球牛流产的主要原因。鉴于目前经济损失严重且缺乏针对此类寄生虫的有效控制策略,开发有效疫苗候选物和技术的挑战仍然存在。我们研究了刚地弓形虫亲环蛋白(NcCyp)及其与寡甘露糖包被脂质体(OML)联合应用的免疫刺激活性,OML 作为潜在的佐剂。NcCyp-OML 可激活 RAW 264.7 细胞中的 NF-κB,并触发小鼠腹腔巨噬细胞产生白细胞介素(IL)-12p40。在 BALB/c 小鼠中,NcCyp-OML 免疫接种与特异性抗体(IgG1 和 IgG2a)的产生有关。在挑战感染后也观察到针对裸露 NcCyp 的特异性抗体(IgG1),但其水平明显低于 NcCyp-OML。此外,还诱导了明显的细胞免疫反应,包括脾细胞增殖和干扰素-γ的产生。与 PBS 对照组相比,用 NcCyp-OML 免疫接种小鼠,在较小程度上用裸露 NcCyp 免疫接种,可显著保护其免受致死剂量的刚地弓形虫感染。这种保护与更高的存活率、体重变化轻微和小鼠临床评分降低有关。此外,在另一种小鼠品系雄性 C57BL/6 小鼠中也证实了 NcCyp-OML 的显著保护功效。本研究表明 Toll 样受体 2(TLR2)对 NcCyp-OML 引发的保护性免疫具有显著贡献,因为与 C57BL/6 小鼠相比,TLR2 敲除小鼠对致死剂量的刚地弓形虫更易感染。此外,NcCyp-OML 免疫接种小鼠中还通过 TLR2 依赖的机制诱导了明显的脾细胞增殖和 IFN-γ 产生。