Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates
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, Eunha Hwang, Seung Ho Baek, Hyeong-Jun Park, Yu‐Sun Lee, Yoo‐Jin Bang, Jaeyong Kim, Seo‐Hyeon Bae, Su Jeen Lee, Ki-Weon Seo, Hak Kim, Taewoo Kwon, Ji Hwan Kim, Seonghwan Lee, Eunsom Kim, Yeon‐Hwa 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
Abstract
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.