Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India.
Department of Immunology, Indian Institute of Chemical Biology (IICB), 4, Raja S.C. Mullick Road, Jadavpur, Calcutta, 700032, WB, India.
Microbes Infect. 2018 Jan;20(1):37-47. doi: 10.1016/j.micinf.2017.09.011. Epub 2017 Sep 29.
This study is aimed to evaluate the protective effect of L. donovani intracellular serine protease (SP-Ld) in combination with Freund's adjuvant and liposomal formulations against experimental visceral leishmaniasis (VL). The animals were immunized with SP-Ld in combination with adjuvant and evaluated for its immunogenicity and protective efficacy against Leishmania donovani. The infection was initially assessed by microscopic examination. Immunogenicity of SP-Ld was measured by detecting protease specific-IgG, IgG1 and IgG2a levels by ELISA. Cytokines levels were measured by ELISA and Reverse Transcription Polymerase Chain Reaction (RT-PCR). The vaccine efficacy of SP-Ld was also evaluated by measuring antibody response and survival potency in hamster model. SP-Ld vaccinated Balb/c mice resulted significant reduction of parasite burden with increased levels of IgG2a and decreased levels of IgG1. SP-Ld vaccination also induced Th1 type immune response with the rise of IL-12, IFN-γ and TNF-α with decreased levels of IL-10 and TGF-β. Importantly, liposomal incorporated SP-Ld exerted better protection rather than in combination with Freund's adjuvant. Additionally, liposome encapsulated SP-Ld vaccinated hamsters continued to survive beyond 8 months against virulent L. donovani post challenge. Overall, these findings demonstrated SP-Ld as an effective immunogen which opens a new perspective for the generation of potential vaccine candidate against leishmaniasis.
本研究旨在评估利什曼原虫细胞内丝氨酸蛋白酶(SP-Ld)与弗氏佐剂和脂质体制剂联合应用对实验性内脏利什曼病(VL)的保护作用。用 SP-Ld 与佐剂联合免疫动物,并评价其对利什曼原虫的免疫原性和保护效果。最初通过显微镜检查评估感染情况。通过 ELISA 检测蛋白酶特异性 IgG、IgG1 和 IgG2a 水平来测量 SP-Ld 的免疫原性。通过 ELISA 和逆转录聚合酶链反应(RT-PCR)测量细胞因子水平。还通过测量抗体反应和在仓鼠模型中的存活能力来评估 SP-Ld 的疫苗效力。SP-Ld 接种的 Balb/c 小鼠寄生虫负荷显著减少,IgG2a 水平升高,IgG1 水平降低。SP-Ld 疫苗接种还诱导了 Th1 型免疫反应,IL-12、IFN-γ 和 TNF-α水平升高,IL-10 和 TGF-β水平降低。重要的是,与弗氏佐剂联合应用相比,脂质体包封的 SP-Ld 发挥了更好的保护作用。此外,脂质体包封的 SP-Ld 接种仓鼠在受到强毒 L. donovani 攻击后,其存活时间超过 8 个月。总的来说,这些发现表明 SP-Ld 是一种有效的免疫原,为开发针对利什曼病的潜在疫苗候选物开辟了新的前景。