Akbari Mohammad Reza, Saadati Mojtaba, Honari Hosein, Ghorbani Hadi Mohammad
Center of Biological Science and Technology, Imam Hosein University, Tehran, Iran.
Iran J Immunol. 2019 Sep;16(3):212-224. doi: 10.22034/IJI.2019.80272.
Shigella flexneri is a pathogen responsible for shigellosis around the world, especially in developing countries. Many immunogenic antigens have been introduced as candidate vaccines against Shigella, including N-terminal region of IpaD antigen (NIpaD).
To evaluate the efficiency of O-metylated free trimethyl chitosan nanoparticles (TMC NPs) in the oral delivery of NIpaD.
TMC was synthesized by a two-step method from high molecular weight chitosan. The recombinant NIpaD protein was used as the immunogen. The protein was overexpressed in E. coli BL21 (DE3) and characterized by gel electrophoresis. The NIpaD-loaded TMC NPs were synthesized by ionic gelation method and were characterized by electron microscopy. NPs were orally administered to guinea pigs and specific humoral and mucosal immune responses were assessed by serum IgG and secretory IgA, respectively. The protectivity of the formulation was assessed by keratoconjunctivitis (Sereny) test.
The immunized guinea pigs showed a significant raise in rNIpaD-specific serum IgG and faecal IgA titers. Specific secretory IgA was detected in eye-washes. Sereny test results showed that immunized animals vaccinated with IpaD-loaded TMC NPS tolerated the wild type of Shigella flexneri 2a in Sereny test. However, in the group immunized with NIpaD antigen and non-immunized group, no increase was observed in antibody titer against NIpaD. These animals were infected following the challenge with Shigella flexneri 2a (p<0.0152).
The recombinant rNIpaD formulated with TMC obtained from high molecular weight chitosan, can be considered as a mucosal vaccine against Shigella flexneri through oral route.
福氏志贺菌是全球尤其是发展中国家引起志贺氏菌病的病原体。许多免疫原性抗原已被用作抗志贺菌的候选疫苗，包括IpaD抗原的N端区域（NIpaD）。
评估O-甲基化游离三甲基壳聚糖纳米颗粒（TMC NPs）口服递送NIpaD的效率。
通过两步法由高分子量壳聚糖合成TMC。重组NIpaD蛋白用作免疫原。该蛋白在大肠杆菌BL21（DE3）中过表达并通过凝胶电泳进行表征。通过离子凝胶法合成负载NIpaD的TMC NPs，并通过电子显微镜进行表征。将纳米颗粒口服给予豚鼠，并分别通过血清IgG和分泌型IgA评估特异性体液和黏膜免疫反应。通过角膜结膜炎（Sereny）试验评估制剂的保护作用。
免疫的豚鼠rNIpaD特异性血清IgG和粪便IgA滴度显著升高。在洗眼液中检测到特异性分泌型IgA。Sereny试验结果表明，用负载IpaD的TMC NPS免疫的动物在Sereny试验中耐受野生型福氏志贺菌2a。然而，在用NIpaD抗原免疫的组和未免疫组中，未观察到针对NIpaD的抗体滴度增加。在用福氏志贺菌2a攻击后，这些动物被感染（p<0.0152）。
由高分子量壳聚糖获得的TMC配制的重组rNIpaD可被视为通过口服途径抗福氏志贺菌的黏膜疫苗。
