Sedaghat M, Siadat S D, Shahcheraghi F, Mirabzadeh Ardakani E, Keramati M, Vaziri F, Nojoumi S A
Department of Bacteriology, Pasteur Institute of Tehran, Iran.
Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran.
Arch Razi Inst. 2021 Jan;75(4):451-461. doi: 10.22092/ari.2019.126909.1365. Epub 2021 Jan 1.
Cholera, a life-threatening disease caused by the Gram-negative bacterium Vibrio cholera, remains a concern in developing countries. The present study investigated the immunogenicity and protective immunity of outer membrane vesicles (OMVs) and combination of OMV and killed whole cells (WC) of a local strain isolated from the last outbreak in Iran in addition to reference and local strains of V. cholerae El Tor O1 in comparison to Dukoral vaccine in mice model. The protein content, morphology, and size of extracted OMVs were evaluated by electrophoresis and microscopic analyses, respectively. The serum titers of total immunoglobulin G (IgG), IgG1, IgG2a, and immunoglobulin A (IgA) in addition to secretory IgA and total IgG in different mice groups were determined by enzyme-linked immunosorbent assay (ELISA). In addition, fluid accumulation (FA) assay regarding the resistance to live strain of V. cholerae in ligated ileal loops was carried out to determine immunogenicity by OMV or combination of OMV and WC in comparison to that reported for Dukoral vaccine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified OMVs indicated protein profiles within the range of 34-52 kDa. Furthermore, transmission electron microscopy demonstrated the spherical shaped vesicles of 50-200 nm. The results of ELISA showed significant titers of systemic and mucosal immune anti-OMV IgGs in immunized BALB/c mice with different vaccine regimens. Additionally, a notable increase in the FA ratio was demonstrated in this study. The obtained results of the present study revealed that the WC-OMV combination of local strain can induce a high level of antibody response indicating more protection than OMV or WC separately. Moreover, it can be considered an effective immunogen against V. cholerae.
霍乱是一种由革兰氏阴性菌霍乱弧菌引起的危及生命的疾病，在发展中国家仍然是一个令人担忧的问题。本研究调查了从伊朗上一次疫情中分离出的一株本地菌株的外膜囊泡（OMV）以及OMV与灭活全菌（WC）组合的免疫原性和保护性免疫，此外还研究了霍乱弧菌埃尔托O1型的参考菌株和本地菌株，并与杜科拉尔疫苗在小鼠模型中进行了比较。分别通过电泳和显微镜分析评估提取的OMV的蛋白质含量、形态和大小。通过酶联免疫吸附测定（ELISA）测定不同小鼠组中总免疫球蛋白G（IgG）、IgG1、IgG2a和免疫球蛋白A（IgA）的血清滴度，以及分泌型IgA和总IgG。此外，进行了关于结扎回肠袢中对霍乱弧菌活菌株抗性的液体蓄积（FA）试验，以确定OMV或OMV与WC组合相对于杜科拉尔疫苗所报道的免疫原性。纯化的OMV的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示蛋白质谱在34-52 kDa范围内。此外，透射电子显微镜显示为50-200 nm的球形囊泡。ELISA结果显示，用不同疫苗方案免疫的BALB/c小鼠中，全身和黏膜免疫抗OMV IgG的滴度显著。此外，本研究还显示FA比率有显著增加。本研究获得的结果表明，本地菌株的WC-OMV组合可诱导高水平的抗体反应，表明比单独的OMV或WC具有更强的保护作用。此外，它可被认为是一种针对霍乱弧菌的有效免疫原。
