Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates
Authors
So-Hee Hong ; Hanseul Oh ; Yong Wook Park ; Hye Won Kwak ; Eun Young Oh ; Hyo-Jung Park ; Kyung Won Kang ; Green Kim ; Bon-Sang Koo ; Eun-Ha Hwang ; Seung Ho Baek ; Hyeong-Jun Park ; Yu-Sun Lee ; Yoo-Jin Bang ; Jae-Yong Kim ; Seo-Hyeon Bae ; Su Jeen Lee ; Ki-Weon Seo ; Hak Kim ; Taewoo Kwon ; Ji-Hwan Kim ; Seonghwan Lee ; Eunsom Kim ; Yeonhwa Kim ; Jae-Hak Park ; Sang-In Park ; Marta Gonçalves ; Byung Mook Weon ; Haengdueng Jeong ; Ki Taek Nam ; Kyung-Ah Hwang ; Jihye Kim ; Hun Kim ; Sang-Myeong Lee ; Jung Joo Hong ; Jae-Hwan Nam
Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.