Suphatrakul Amporn, Yasanga Thippawan, Keelapang Poonsook, Sriburi Rungtawan, Roytrakul Thaneeya, Pulmanausahakul Rojjanaporn, Utaipat Utaiwan, Kawilapan Yanee, Puttikhunt Chunya, Kasinrerk Watchara, Yoksan Sutee, Auewarakul Prasert, Malasit Prida, Charoensri Nicha, Sittisombut Nopporn
Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand.
Medical Science Research Equipment Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
Vaccine. 2015 Oct 13;33(42):5613-5622. doi: 10.1016/j.vaccine.2015.08.090. Epub 2015 Sep 14.
Recent phase IIb/III trials of a tetravalent live attenuated vaccine candidate revealed a need for improvement in the stimulation of protective immunity against diseases caused by dengue type 2 virus (DENV-2). Our attempts to develop particulate antigens for possibly supplementing live attenuated virus preparation involve generation and purification of recombinant DENV-2 virus-like particles (VLPs) derived from stably (prM+E)-expressing mosquito cells. Two VLP preparations generated with either negligible or enhanced prM cleavage exhibited different proportions of spherical particles and tubular particles of variable lengths. In BALB/c mice, VLPs were moderately immunogenic, requiring adjuvants for the induction of strong virus neutralizing antibody responses. VLPs with enhanced prM cleavage induced higher levels of neutralizing antibody than those without, but the stimulatory activity of both VLPs was similar in the presence of adjuvants. Comparison of EDIII-binding antibodies in mice following two adjuvanted doses of these VLPs revealed subtle differences in the stimulation of anti-EDIII binding antibodies. In cynomolgus macaques, VLPs with enhanced prM cleavage augmented strongly neutralizing antibody and EDIII-binding antibody responses in live attenuated virus-primed recipients, suggesting that these DENV-2 VLPs may be useful as the boosting antigen in prime-boost immunization. As the levels of neutralizing antibody induced in macaques with the prime-boost immunization were comparable to those infected with wild type virus, this virus-prime VLP-boost regimen may provide an immunization platform in which a need for robust neutralizing antibody response in the protection against DENV-2-associated illnesses could be tested.
近期一项四价减毒活疫苗候选物的IIb/III期试验表明，在刺激针对2型登革热病毒（DENV-2）所致疾病的保护性免疫方面仍有改进的必要。我们尝试开发颗粒抗原以辅助减毒活病毒制剂，这涉及从稳定表达（prM+E）的蚊细胞中生成并纯化重组DENV-2病毒样颗粒（VLP）。两种prM切割程度可忽略不计或增强的VLP制剂呈现出不同比例的球形颗粒和长度各异的管状颗粒。在BALB/c小鼠中，VLP具有中等免疫原性，需要佐剂来诱导强烈的病毒中和抗体反应。prM切割增强的VLP诱导产生的中和抗体水平高于未增强的VLP，但在佐剂存在的情况下，两种VLP的刺激活性相似。比较用这两种VLP进行两次佐剂免疫后的小鼠体内EDIII结合抗体发现，在刺激抗EDIII结合抗体方面存在细微差异。在食蟹猴中，prM切割增强的VLP在减毒活病毒初免的受体中强烈增强了中和抗体和EDIII结合抗体反应，这表明这些DENV-2 VLP可能作为初免-加强免疫中的加强抗原。由于初免-加强免疫在食蟹猴中诱导产生的中和抗体水平与野生型病毒感染诱导的水平相当，这种病毒初免-VLP加强方案可能提供一个免疫平台，在此平台上可以测试在预防DENV-2相关疾病中对强大中和抗体反应的需求。
