Cross-reactive Antibody Response between SARS-CoV-2 and SARS-CoV Infections.

Lv, Huibin; Wu, Nicholas C; Tsang, Owen Tak-Yin; Yuan, Meng; Perera, Ranawaka A P M; Leung, Wai Shing; So, Ray T Y; Chan, Jacky Man Chun; Yip, Garrick K; Chik, Thomas Shiu Hong; Wang, Yiquan; Choi, Chris Yau Chung; Lin, Yihan; Ng, Wilson W; Zhao, Jincun; Poon, Leo L M; Peiris, J S Malik; Wilson, Ian A; Mok, Chris K P; Tak-Yin Tsang, Owen; Chun Chan, Jacky Man; Hong Chik, Thomas Shiu; Chung Choi, Chris Yau

The World Health Organization has declared the ongoing outbreak of COVID-19, which is caused by a novel coronavirus SARS-CoV-2, a pandemic. There is currently a lack of knowledge about the antibody response elicited from SARS-CoV-2 infection. One major immunological question concerns antigenic differences between SARS-CoV-2 and SARS-CoV. We address this question by analyzing plasma from patients infected by SARS-CoV-2 or SARS-CoV and from infected or immunized mice. Our results show that, although cross-reactivity in antibody binding to the spike protein is common, cross-neutralization of the live viruses may be rare, indicating the presence of a non-neutralizing antibody response to conserved epitopes in the spike. Whether such low or non-neutralizing antibody response leads to antibody-dependent disease enhancement needs to be addressed in the future. Overall, this study not only addresses a fundamental question regarding antigenicity differences between SARS-CoV-2 and SARS-CoV but also has implications for immunogen design and vaccine development.