RBD-Modified Bacterial Vesicles Elicited Potential Protective Immunity against SARS-CoV-2

Yang, Zhongqian; Hua, Liangqun; Yang, Mengli; Liu, Shu-Qun; Shen, Jianxin; Li, Weiran; Long, Qiong; Bai, Hongmei; Yang, Xu; Ren, Zhaoling; Zheng, Xiao; Sun, Wenjia; Ye, Chao; Li, Duo; Zheng, Peng; He, Jinrong; Chen, Yongjun; Huang, Weiwei; Peng, Xiaozhong; Ma, Yanbing

[Image: see text] The disease caused by SARS-CoV-2 infection threatens human health. In this study, we used high-pressure homogenization technology not only to efficiently drive the bacterial membrane to produce artificial vesicles but also to force the fusion protein ClyA-receptor binding domain (RBD) to pass through gaps in the bacterial membrane to increase the contact between ClyA-RBD and the membrane. Therefore, the load of ClyA-RBD on the membrane is substantially increased. Using this technology, we constructed a “ring-like” bacterial biomimetic vesicle (BBV) loaded with polymerized RBD (RBD-BBV). RBD-BBVs injected subcutaneously can accumulate in lymph nodes, promote antigen uptake and processing, and elicit SARS-CoV-2-specific humoral and cellular immune responses in mice. In conclusion, we evaluated the potential of this novel bacterial vesicle as a vaccine delivery system and provided a new idea for the development of SARS-CoV-2 vaccines.