Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Vaccine. 2022 Apr 1;40(15):2299-2310. doi: 10.1016/j.vaccine.2022.02.070. Epub 2022 Mar 11.
There is an urgent need for a safe and effective vaccine against dengue virus (DENV) which infects about 390 million humans per year. In the present study we combined modifications of two DENV proteins, the nonstructural protein 1 (NS1) and the envelope (E) protein, to produce a DENV vaccine candidate with enhanced features. One of these modified proteins was a C-terminal-deleted fragment of NS1 called ΔC NS1 which we have shown previously to be protective without the potentially harmful effects of cross-reactive epitopes common to surface antigens on platelets and endothelial cells. The other modified protein was an envelope protein domain III (cEDIII) containing a consensus amino acid sequence among the four serotypes of DENV, which induces neutralizing antibody against all four DENV serotypes. The cEDIII and ΔC NS1 were expressed as a fusion protein cEDIII-ΔC NS1 and its protective effects against DENV were evaluated in a mouse model. C3H/HeN mice were immunized three times with cEDIII-ΔC NS1 fusion protein mixed with alum as adjuvant. Sera collected from cEDIII-ΔC NS1-immunized mice neutralized four serotypes of DENV and also caused complement-mediated cytolysis of HMEC-1 cells infected with each of the four different DENV serotypes. Mice immunized with cEDIII-ΔC NS1 and challenged with DENV showed reduced serum virus titer, soluble NS1 and bleeding time, compared with mice infected with DENV alone. The results reveal that antibodies induced by cEDIII-ΔC NS1 not only show anti-viral efficacy by in vitro assays but also provide protective effects against DENV infection in a mouse model. The cEDIII-ΔC NS1 thus represents a novel, effective DENV vaccine candidate.
目前迫切需要一种安全有效的登革热病毒（DENV）疫苗，该病毒每年感染约 3.9 亿人。在本研究中，我们将两种 DENV 蛋白（非结构蛋白 1（NS1）和包膜（E）蛋白）进行修饰，以产生一种具有增强特征的 DENV 疫苗候选物。其中一种修饰蛋白是 NS1 的 C 端缺失片段，称为 ΔC NS1，我们之前已经证明它具有保护作用，而没有血小板和内皮细胞表面抗原上常见的交叉反应表位的潜在有害影响。另一种修饰蛋白是包膜蛋白结构域 III（cEDIII），它包含 DENV 四个血清型之间的保守氨基酸序列，可诱导针对所有四个 DENV 血清型的中和抗体。cEDIII 和 ΔC NS1 被表达为融合蛋白 cEDIII-ΔC NS1，并在小鼠模型中评估其对 DENV 的保护作用。C3H/HeN 小鼠用 cEDIII-ΔC NS1 融合蛋白与明矾混合作为佐剂进行三次免疫。从 cEDIII-ΔC NS1 免疫小鼠收集的血清中和了四种 DENV 血清型，并且还导致补体介导的感染了四种不同 DENV 血清型的 HMEC-1 细胞的细胞溶解。与单独感染 DENV 的小鼠相比，用 cEDIII-ΔC NS1 免疫并接受 DENV 挑战的小鼠的血清病毒滴度、可溶性 NS1 和出血时间降低。结果表明，cEDIII-ΔC NS1 诱导的抗体不仅通过体外试验显示出抗病毒功效，而且在小鼠模型中还提供了针对 DENV 感染的保护作用。因此，cEDIII-ΔC NS1 代表了一种新型有效的 DENV 疫苗候选物。
