Yang Huijie, Xie Ying, Lu Shuaiyao, Sun Yufang, Wang Kaiqin, Li Shuyan, Wang Junzhi, Liao Guoyang, Li Changgui
Divsion of Respiratory Virus Vaccines, National Institutes for Food and Drug Control, Beijing 102629, China.
Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650108, China.
Vaccines (Basel). 2023 Nov 2;11(11):1681. doi: 10.3390/vaccines11111681.
Of all of the components in SARS-CoV-2 inactivated vaccines, nucleocapsid protein (N) is the most abundant and highly conserved protein. However, the function of N in these vaccines, especially its influence on the targeted spike protein's response, remains unknown. In this study, the immunization of mice with the N protein alone was shown to reduce the viral load, alleviating pulmonary pathological lesions after challenge with the SARS-CoV-2 virus. In addition, co-immunization and pre-immunization with N were found to induce higher S-specific antibody titers rather than compromise them. Remarkably, the same trend was also observed when N was administered as the booster dose after whole inactivated virus vaccination. N-specific IFN-γ-secreting T cell response was detected in all groups and exhibited a certain relationship with S-specific IgG antibody improvements. Together, these data indicate that N has an independent role in vaccine-induced protection and improves the S-specific antibody response to inactivated vaccines, revealing that an interplay mechanism may exist in the immune responses to complex virus components.
在严重急性呼吸综合征冠状病毒2（SARS-CoV-2）灭活疫苗的所有成分中，核衣壳蛋白（N）是含量最丰富且高度保守的蛋白。然而，N在这些疫苗中的功能，尤其是其对靶向刺突蛋白反应的影响，仍然未知。在本研究中，单独用N蛋白免疫小鼠可降低病毒载量，减轻感染SARS-CoV-2病毒后的肺部病理损伤。此外，发现用N进行联合免疫和预免疫可诱导更高的S特异性抗体滴度，而非损害它们。值得注意的是，在全病毒灭活疫苗接种后以N作为加强剂量时也观察到了相同趋势。在所有组中均检测到了N特异性分泌γ干扰素的T细胞反应，且其与S特异性IgG抗体的改善存在一定关系。总之，这些数据表明N在疫苗诱导的保护中具有独立作用，并改善了对灭活疫苗的S特异性抗体反应，揭示了对复杂病毒成分的免疫反应中可能存在相互作用机制。
