Zareitaher Tahereh, Sadat Ahmadi Tooba, Latif Mousavi Gargari Seyed
Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran.
Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran.
Immunobiology. 2022 Mar;227(2):152190. doi: 10.1016/j.imbio.2022.152190. Epub 2022 Feb 16.
Vibrio cholerae is one of the major causes of morbidity and mortality in developing countries. CtxB, responsible for toxin binding to eukaryotic cells, TcpA, involved in bacterial colonization, and OmpW, the highly conserved extracellular protein, are the three of the significant essential virulence factors in V. cholerae with enhanced immunogenic properties. Increasing emergence of antimicrobial-resistant strains (AMR) highlights the urgent need for new therapeutic agents. Uncomplicated high yield production, simple design, inducing either or both humoral and cellular immunity, and long-term immune responsiveness are some of the advantages of IgG antibodies over other immunotherapy agents. Chimeric proteins have the potential of presenting multiple antigens to immune system, simultaneously. Thus, the current study was aimed to evaluate the stability and protective efficacy of DNA and protein-based vaccine candidates of a chimeric gene harboring OTC (OmpW, TcpA and CtxB) against V. cholerae. The immunogenicity and specificity of induced IgGs were confirmed through indirect ELISA and western blot analysis, respectively. The DNA and protein immunized mice sera were able to neutralize the cytotoxicity effects of the cholera toxin (CT) at 5% and 10% dilutions in Y1 cell line, and inhibited 60% and 68% of the bacterial adhesion to HT-29 cells, respectively. The DNA and protein immunized sera provided 99% and 95% viability percent in spleen cell viability assays, and inhibited the bacteria-induced fluid accumulation in ileal loop assay at 1/80 and 1/160 dilutions, respectively. Different groups of passively immunized infant mice and actively immunized adult mice were challenged with V. cholerae. The OTC construct provided high survival rates against lethal infection, and significantly reduced the bacterial loads. Our results highlight the potential therapeutic effect of the recombinant OTC chimeric construct, either as a DNA or protein vaccine, due to its remarkable immunogenicity and protectivity against V. cholerae.
霍乱弧菌是发展中国家发病和死亡的主要原因之一。CtxB负责毒素与真核细胞结合，TcpA参与细菌定植，OmpW是高度保守的细胞外蛋白，它们是霍乱弧菌中具有增强免疫原性的三个重要必需毒力因子。抗菌耐药菌株（AMR）的不断出现凸显了对新型治疗药物的迫切需求。IgG抗体相对于其他免疫治疗药物具有一些优势，如高产率生产简单、设计简单、可诱导体液免疫和细胞免疫中的一种或两种，以及长期免疫反应性。嵌合蛋白有可能同时向免疫系统呈递多种抗原。因此，本研究旨在评估携带OTC（OmpW、TcpA和CtxB）的嵌合基因的基于DNA和蛋白质的候选疫苗对霍乱弧菌的稳定性和保护效果。分别通过间接ELISA和western blot分析证实了诱导IgG的免疫原性和特异性。DNA免疫和蛋白质免疫小鼠血清在Y1细胞系中分别以5%和10%的稀释度能够中和霍乱毒素（CT）的细胞毒性作用，并分别抑制60%和68%的细菌对HT-29细胞的粘附。DNA免疫和蛋白质免疫血清在脾细胞活力测定中分别提供了99%和95%的活力百分比，并分别在1/80和1/160稀释度下抑制了回肠袢试验中细菌诱导的液体蓄积。不同组的被动免疫幼鼠和主动免疫成年鼠用霍乱弧菌进行攻击。OTC构建体对致死性感染提供了高存活率，并显著降低了细菌载量。我们的结果突出了重组OTC嵌合构建体作为DNA或蛋白质疫苗的潜在治疗效果，因为它对霍乱弧菌具有显著的免疫原性和保护性。
