Coronavirus: Two antibodies identified for potential drug treatment by Chinese scientists

Chinese scientists say they have identified two antibodies that could be candidates for a cocktail treatment for patients with different strains of the coronavirus. The antibodies were found to work together as a team to prevent the virus from latching onto a host cell, in a study led by Chinese Centre for Disease Control and Prevention director George Fu Gao with collaborators from across the country. They said that even a mutant strain was likely to be neutralised because the antibodies targeted different parts of the spike protein, which the virus uses to bind to cells. The two antibodies were “promising candidates for prophylactic and therapeutic treatment against the Covid-19 virus”, Gao said in a non-peer reviewed paper posted on preprint service medRxiv.org on Thursday. Months after it was first reported in central China late last year, there is still no effective treatment or vaccine for the new coronavirus. As it has spread around the world, infecting more than 3.8 million people and killing roughly 270,000 so far, the virus has evolved into many different strains. More than 6,000 have been recorded so far, according to the China National Centre for Bioinformation. Computer models suggest some of those virus mutations could be more contagious and more deadly. And according to some studies, a few small changes to its genes could affect the efficacy of many drug and vaccine candidates in development. In their study, Gao and his team added the viral spike protein to blood samples taken from a recovered Covid-19 patient in Shenzhen. They wanted to activate an immune response from the memory B cells, which are formed after an infection and can survive and create antibodies to neutralise a virus for decades. Their inspiration came from using the plasma – the fluid part of blood – of recovered patients to treat Covid-19 after an initial trial on 10 people in Wuhan found that it significantly relieved their symptoms within a week. They wanted to know how many different antibodies were generated and needed by a patient. Gao’s team identified four types of antibodies in the recovered patient’s samples, all produced by the memory B cells. All were drawn to the binding protein, as expected, but two of the antibodies were less effective in fending off the virus. The other two – fork-shaped molecules dubbed B38 and H4 – went straight for the virus, binding to its spike protein and making it much harder for it to latch onto a host cell. The researchers also found that instead of targeting the same area of the virus, these two antibodies did not compete with each other, instead zeroing in on different parts – or epitopes – of the spike protein. Scientists around the world are working on antibody treatments, but most involve just one type of antibody. That means a single mutation of the target epitope could potentially render the drug useless. Having identified the two antibodies, Gao’s team tested them on mice, reporting a significant improvement in weight loss, viral load and lung injury. “Cocktail antibodies should be considered as an alternative therapeutic strategy to avoid potential escape [mutant strains],” Gao wrote in the paper. US study says suppressing body’s initial immune response may help against Covid-19 He added that the team’s findings also “provide the structural basis of rational vaccine design”. But there are safety concerns about antibody treatments. A joint study by a team from China and the United States in February found that the coronavirus could enter some cells they previously could not infect by making use of an antibody attached to the spike protein. The virus appeared to be using the antibody to dodge the immune response, according to the paper in the Journal of Virology. That phenomenon – known as antibody-dependent enhancement, or ADE – could make the disease much worse. “ADE is a nightmare for vaccine and antibody drug developers because it can potentially turn a treatment into a poison,” said a Beijing-based scientist studying the coronavirus who declined to be named. Synthetic coronavirus created with brewer’s yeast comes with research options, hope and a warning Some critically ill Covid-19 patients have also been found to have high levels of antibodies as well as extreme inflammation, and that could be a sign of ADE, Yale University scientists Akiko Iwasaki and Yexin Yang wrote in Nature Reviews Immunology last month. But they said man-made antibodies could reduce the risk – with precise design and careful evaluation. “Safe and effective neutralising antibodies could be produced on a mass scale for delivery to populations across the world in the coming months,” they wrote.

Coronavirus: Two antibodies identified for potential drug treatment by Chinese scientists

.css-1mniedq{color:inherit;font-weight:inherit;font-size:inherit;font-family:inherit;line-height:inherit;} The antibodies were found to work together as a team to prevent the virus from binding to a host cell Researchers say that could help target different strains that evolve as virus spreads

The antibodies were found to work together as a team to prevent the virus from binding to a host cell

Researchers say that could help target different strains that evolve as virus spreads