Chinese scientists say a new drug is showing promising results in treating and preventing COVID-19, which could be effective in ending the pandemic before a vaccine is ready. But, VOA News reports, US scientists say the Chinese treatment “has potential,” but it may take a long time before determining if it is a realistic option.
The report quotes scientists at Peking University as saying that they took antibodies gathered from 60 people who recovered from COVID-19 and then determined which specific antibodies were most effective in killing the coronavirus in animal studies. They say their process may not only shorten the recovery time of COVID-19 patients but could provide short-term immunity to the virus. The treatment itself is called “passive immunization.”
“It is analogous to a breast-feeding baby that ingests its mother’s antibodies while nursing. The maternal antibodies help to protect the baby from infection,” said Dr Laura H Kahn, a senior scholar at Princeton University’s Programme on Science and Global Security. “These COVID-19 antibodies should theoretically help neutralise the virus and help prevent the disease, depending on how long the antibodies stay in the body.”
Dr Zong-Mei Sheng, a vaccine expert with the National Institute of Allergy and Infectious Diseases, explained that the treatment works similar to donated plasma from recovered patients. “I will not call it a drug. This is an antibody, just like right now, a hospital uses recovered patients’ plasma which contains neutralising antibodies.” Sheng told VOA that the SARS-CoV-2 neutralising antibody can guard against the coronavirus so it can be used as both a treatment and prevention.
The Chinese treatment also could address one of the main problems in using donated plasma from recovered patients: the amount currently needed to fight the pandemic. Sheng said that “because in patients, plasma cannot be produced on a large scale, that’s why they (Chinese study) try to use B-cell to make more. It’s a good idea, but it’s a long process, and I don’t know whether it can be realistic,” she said.
The report says the Chinese process essentially took antibodies from the 60 patients and ran them through sophisticated computers that sequence the various antibodies and determine how many kinds there are in the patients. Doctors then took those antibodies and treated infected mice.
The study’s lead scientist, Peking University’s Sunney Xie, said that the drug had been a success in animal trials.
The report says given that this study has only completed clinical trials in small animals, it is an open question how long it will take before it can turn into an effective drug specifically for COVID-19. Kahn told VOA that “it has to undergo Phase 1, 2 and 3 clinical studies to assess efficacy and safety before being approved for widespread use.
Abstract
The COVID-19 pandemic urgently needs therapeutic and prophylactic interventions. Here, we report the rapid identification of SARS-CoV-2-neutralizing antibodies by high-throughput single-cell RNA and VDJ sequencing of antigen-enriched B cells from 60 convalescent patients. From 8,558 antigen-binding IgG1+ clonotypes, 14 potent neutralizing antibodies were identified, with the most potent one, BD-368-2, exhibiting an IC50 of 1.2 and 15 ng/mL against pseudotyped and authentic SARS-CoV-2, respectively. BD-368-2 also displayed strong therapeutic and prophylactic efficacy in SARS-CoV-2-infected hACE2-transgenic mice. Additionally, the 3.8 Å cryo-EM structure of a neutralizing antibody in complex with the spike-ectodomain trimer revealed the antibody’s epitope overlaps with the ACE2 binding site. Moreover, we demonstrated that SARS-CoV-2-neutralizing antibodies could be directly selected based on similarities of their predicted CDR3H structures to those of SARS-CoV-neutralizing antibodies. Altogether, we showed that human neutralizing antibodies could be efficiently discovered by high-throughput single B cell sequencing in response to pandemic infectious diseases.
Authors
Yunlong Cao, Bin Su, Xianghua Guo, Wenjie Sun, Yongqiang Deng, Linlin Bao, Qinyu Zhu, Xu Zhang, Yinghui Zheng, Chenyang Geng, Xiaoran Chai, Runsheng He, Xiaofeng Li, Qi Lv, Hua Zhu, Wei Deng, Yanfeng Xu, Yanjun Wang, Luxin Qiao, Yafang Tan, Liyang Song, Guopeng Wang, Xiaoxia Du, Ning Gao, Jiangning Liu, Junyu Xiao, Xiao-dong Su, Zongmin Du, Yingmei Feng, Chuan Qin, Chengfeng Qin, Ronghua Jin, X Sunney Xie
[link url="https://www.voanews.com/east-asia-pacific/voa-news-china/promising-covid-19-treatment-uses-antibodies-recovered-patients"]Full VOA News report[/link]
[link url="https://www.cell.com/cell/fulltext/S0092-8674(20)30620-6"]Cell abstract[/link]