A joint study by multiple laboratories in two Hong Kong universities found a broadly neutralizing antibody ZCB11. Isolated from local mRNA vaccine recipients, ZCB11 showed potent antiviral activity against all SARS-CoV-2 variants of concern. In live virus challenge experiments, administration of ZCB11 protects from lung infection by Omicron in golden Syrian hamsters.
In this study, a research team at University of Hong Kong’s (HKU) medical school established an antibody replication technology platform, which is capable of antibody gene amplification of a single memory B cell. Using this technology, the researchers screened blood samples from 34 BNT162b2 vaccine recipients in Hong Kong, and found ZCB11, a potent and broad-spectrum antibody, in the blood from one of these vaccinees.
Through live virus challenge experiments, the researchers confirmed that ZCB11 is able to neutralize all SARS-CoV-2 variants of concern (VOCs), including Alpha variant (B.1.1.7), Beta (B.1.351), Gamma (p1), Delta (B.1.617.2), and Omicron (B.1.1.529).
They only tested single ZCB11 for prophylactic and therapeutic efficacy in the hamster model.
The Golden Syrian hamster model of SARS-CoV-2 infection was performed to determine ZCB11’s prophylaxis (prevention of an infection) and therapeutic efficacy. ZCB11 administration was shown to protect lung infection against both Delta and Omicron BA.1 variants viral challenge in golden Syrian hamsters.
The other research team, from Hong Kong University of Science and Technology (HKUST), used single-particle cryo-electron microscopy to analyze ZCB11-spike protein complex, revealing an atomic-resolution image of ZCB11, laying the foundation for vaccine improvement.
Professor Chen Zhiwei, director of the Institute of AIDS at the University of Hong Kong and head of the Department of Microbiology, School of Clinical Medicine, HKU Faculty of Medicine, who led the research, said the findings showed that ZCB11 is a very promising therapeutic antibody that could be administered to fight against SARS-CoV-2 variants.
