The antibody cocktail will be tested in clinical trials over the next few months
The cocktail, which could treat and temporarily prevent the coronavirus, is advancing to clinical trials researchers at the Laboratory of Human Antibody Research at Tel Aviv University’s Sackler Faculty of Medicine have identified a combination of COVID-19 antibodies that can serve as both medication for patients and preventive treatment for high-risk populations. The antibody cocktail will be tested in clinical trials over the next few months.
The scientific breakthrough was achieved by Dr Natalia Freund and PhD student Michael Mor at TAU’s Sackler Faculty of Medicine and the results of the study are under revision in the PLOS Pathogens journal.
The study also found that asymptomatic COVID-19 sufferers or those who had mild symptoms developed a weaker antibody reaction, and therefore may contract the disease again. By contrast, all severely ill patients analysed in the study developed neutralizing antibodies that are likely to protect them from reinfection.
For the study, Dr Freund and her team sequenced thousands of antibodies produced in the bodies of Israeli COVID-19 patients. The researchers were able to isolate and characterize six antibodies derived from the blood of two severely ill patients. They then proved that combinations of three antibodies at a time are effective against COVID-19, providing natural immunity. The researchers found that the blood’s capacity for neutralising the virus comes from several types of antibodies that simultaneously attack the virus, and the mix neutralises the COVID-19 virus.
“Since the antibodies are natural and remain stable in the blood, one injection can protect against COVID-19 for several weeks, or even several months,” says Freund.
“Our vision is that in the future, the cocktail will be used to treat COVID-19 patients – like the experimental cocktail administered to US President Trump, or as a preventive measure for high-risk populations and medical personnel – until the much-awaited vaccine finally arrives. This cocktail was developed naturally by the patients’, immune systems, which means that it is probably safe for use,” say the researchers.
In the second stage of the project, the researchers tried to isolate specific antibodies that stop the virus from binding to the human cell and replicating itself inside the cell. They identified six different antibodies, obtained from two severely ill participants, and proved that these antibodies are effective in both treating and preventing infection in cell cultures.
The research began in April 2020, soon after the pandemic reached Israel. Dr Freund and her team studied 18 of Israel’s earliest COVID-19 patients. “One question we asked was whether there was any difference between mild and severe cases – about both the quality and quantity of the anti-viral antibodies produced by the immune system. We found a significant statistical difference between the two groups of patients in the ability of their antibodies to neutralise COVID-19: Only a small portion of the mildly ill participants developed neutralising antibodies, and some developed no antibodies whatsoever. Thus, we may assume that people who were infected but remained asymptomatic or developed very mild symptoms, may possibly contract the disease a second time. The blood of all severely ill patients, on the other hand, contained neutralizing antibodies that will probably protect them from reinfection.”
Many experts took part in the project. The participating patients were recruited with the help of Dr David Hagin, Director of Allergy and Immunology at the Tel Aviv Sourasky (Ichilov) Medical Center and Dr. Oren Zimhony, Head of Infectious Diseases at the Kaplan Medical Center. Genetic sequencing of immune cells was conducted in collaboration with the Israeli startup immunai and sequence analysis was done with the help of Dr Gur Yaari of Bar-Ilan University. The antibodies were characterised in collaboration with Prof Jonathan Gershoni and Dr Oren Kobiler of Tel Aviv University. Pseudo-viral neutralisation assays were run with the assistance of Dr Meital Gal-Tanamy and Dr Moshe Dessau of Bar-Ilan University’s Faculty of Medicine in the Galilee. Neutralisation tests for the cocktail of antibodies against the live virus were run in collaboration with Dr Ben Croker of the University of California, San Diego.