Khorattanakulchai Narach, Srisutthisamphan Kanjana, Shanmugaraj Balamurugan, Manopwisedjaroen Suwimon, Rattanapisit Kaewta, Panapitakkul Chalisa, Kemthong Taratorn, Suttisan Nutchanat, Malaivijitnond Suchinda, Thitithanyanont Arunee, Jongkaewwattana Anan, Phoolcharoen Waranyoo
Center of Excellence in Plant-produced Pharmaceuticals, Chulalongkorn University, Bangkok, Thailand.
Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
Front Plant Sci. 2022 Sep 28;13:901978. doi: 10.3389/fpls.2022.901978. eCollection 2022.
Since the outbreak of the coronavirus disease (COVID) pandemic in 2019, the development of effective vaccines to combat the infection has been accelerated. With the recent emergence of highly transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC), there are concerns regarding the immune escape from vaccine-induced immunity. Hence an effective vaccine against VOC with a potent immune response is required. Our previous study confirmed that the two doses of the plant-produced receptor-binding domain (RBD) of SARS-CoV-2 fused with the Fc region of human IgG1, namely Baiya SARS-CoV-2 Vax 1, showed high immunogenicity in mice and monkeys. Here, we aimed to evaluate the immunogenicity of a three-dose intramuscular injection of Baiya SARS-CoV-2 Vax 1 on days 0, 21, and 133 in cynomolgus monkeys. At 14 days after immunization, blood samples were collected to determine RBD-specific antibody titer, neutralizing antibody, and pseudovirus neutralizing antibody titers. Immunized monkeys developed significantly high levels of antigen-specific antibodies against SARS-CoV-2 compared to the control group. Interestingly, the sera collected from immunized monkeys also showed a neutralizing antibody response against the SARS-CoV-2 VOCs; Alpha, Beta, Gamma, Delta, and Omicron. These findings demonstrate that a three-dose regimen of Baiya SARS-CoV-2 Vax 1 vaccine elicits neutralizing immune response against SARS-CoV-2 variants.
自2019年冠状病毒病（COVID）大流行爆发以来，对抗该感染的有效疫苗的研发进程加快。随着最近出现具有高度传播性的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）变异株（VOC），人们担心疫苗诱导的免疫会出现免疫逃逸。因此，需要一种针对VOC且具有强大免疫反应的有效疫苗。我们之前的研究证实，两剂植物生产的与人类IgG1的Fc区域融合的SARS-CoV-2受体结合域（RBD），即博雅SARS-CoV-2疫苗1，在小鼠和猴子中显示出高免疫原性。在此，我们旨在评估在第0、21和133天对食蟹猴进行三剂肌肉注射博雅SARS-CoV-2疫苗1的免疫原性。免疫后14天，采集血样以测定RBD特异性抗体滴度、中和抗体和假病毒中和抗体滴度。与对照组相比，免疫的猴子产生了显著高水平的针对SARS-CoV-2的抗原特异性抗体。有趣的是，从免疫猴子采集的血清也显示出针对SARS-CoV-2变异株（Alpha、Beta、Gamma、Delta和Omicron）的中和抗体反应。这些发现表明，博雅SARS-CoV-2疫苗1的三剂接种方案可引发针对SARS-CoV-2变异株的中和免疫反应。
