Ibacked by a unique type of antibody to fight infection found in bulbs, alpacas and other camellias, a research team at the University of California, San Francisco, has synthesized a molecule they say is one of the most powerful compounds anti-coronavirus tested in a laboratory to date.
Called nanobodys because they are about a quarter the size of the antibodies found in humans and most other animals, these molecules can be put into nicknames and protein cuts to block viruses from merging and infecting cells.
The lab created by the UCSF team is so stable that it can be turned into a dry powder and aerosolized, meaning it would be much easier to administer than the Covid-19 treatments developed using human monoclonal antibodies. While the work is still very preliminary, the goal is to disperse the synthetic nanobod through simple inhaled sprays into the nose or lungs, allowing it to be self-administered and used prophylactically against Covid-19 – if proven safe and effective in both animal tests and clinical trials.
After four months of working around the clock, the team posted the results Monday on the default bioRxiv server. The paper has not yet been reviewed by colleagues, but researchers said they are already in talks to find a partner who can quickly test, produce and distribute the new compound in the hope it could prevent new infections and alleviate the disease in them. who are already infected. “Every day, 5,000 people die from this disease. We would like to find a partner as soon as possible and as soon as possible to do so,” said Peter Walter, a veteran biochemist who lives permanently on many lists. shortlisted of those expected to win a Nobel Prize and who co-led the project with structural biologist Aashish Manglik.
Aware of the bitterness over early announcements of coronavirus therapies, the duo do not want to overload their findings and accept the nanobode, called Aeronab 6, should be tested in clinical trials. But they are enthusiastic because of both how stable the ingredient is and how well it has responded to laboratory tests where it inhibits cell infection by binding wildly to the infamous spot proteins that allow coronavirus particles to enter and infect cells. “Almost is almost like a hut that never lets go,” Walter said.
While the lab results look promising, experts in the field advise caution because no significant work has been done to test the composition in animals. “The critical thing is the data on the animals. We have found things that are very powerful in vitro that do nothing in vivo, “said Dimiter Stanchev Dimitrov, a professor of medicine who runs the Center for Therapeutic Antibodies at the University of Pittsburgh and has developed antibody-based therapies for multiple viruses by including SARS and MERS, two other coronaviruses. He said it could take months to gather the necessary data in animals. “Once these are tested in animal models, then I can get excited.”
Dimitrov said that while administering an antibody therapy through an inhaler was an exciting idea that other groups are also investigating, there may be difficulty in getting a uniformly administered drug into the lungs. “It’s tricky to give antibodies to the lungs,” he said.
The potency of the nanobode against coronavirus was tested at the Pasteur Institute in Paris by Veronica Rezelj, a postdoctoral researcher in the institute’s viral population and pathogen unit. When Rezelj mixed coronavirus and small amounts of nanobodes into cell plates, Vero-E6 cells (derived from the kidney cells of African green monkeys and commonly used in laboratory work) were protected from infection and survived.
“Within four days of receiving the package from the US, we knew we had a very powerful nanobode,” she said. “Very little nanobody was needed to completely remove the virus infectivity.” She said the effectiveness of the nanobode was much higher than in published data regarding the neutralization of antibodies obtained from the blood of Covid-19 patients, or other synthetically produced nanobodes.
Rezelj has tested many antivirals against coronavirus in recent months; many will not work either in cell culture or animal models, let alone humans. Nano-organs, she said, are more promising: “We are very confident that they can function from a therapeutic point of view once human clinical trials are completed.”
Dozens of related therapies using human monoclonal antibodies are being developed for use against coronavirus, with some already in clinical trials, but Walter and Manglik are skeptical about how widespread and practical those approaches will be: They are expensive to produce. in mammalian cells, it should be administered intravenously by medical personnel, and require high doses because they travel through the bloodstream before reaching the lungs. UCSF researchers think an effective approach could be to target the nasal passages, where the virus can first be placed before it is implanted in the lungs.
Their compound, they say, can be produced cheaply in large quantities using bacteria or yeast, and will require low doses because it is so powerful against the virus and can be administered directly into the lungs or nasal passages. “We would like this to be made available to developing countries,” Walter said. “This is possible because it can be shipped as a dry powder and must be very cheap to produce.”
Other laboratories around the world, including the University of Oxford and the Rosalind Franklin Institute, have recently published work on synthetic nanobodes. In May, a group at the University of Texas showed real llama antibodies that had been engineered in the laboratory to help prevent coronavirus infection in laboratory studies. And this week, a team from China reported on bioRxiv that it produced camel nanobody active against the Covid-19 virus.
Markus Seeger, an assistant professor at the Institute for Medical Microbiology at the University of Zurich, was one of the first to publish work on synthetic nanobodes, or symbols, as he calls them, for use against coronavirus, and he recently signed a partnership with Absolute Antibodies to make compounds available for research. Seeger said many laboratories are working on compounds because they are inexpensive to produce, easier to optimize than human antibodies, and potentially potent for therapeutic, prophylactic, and even use in masks and surfaces for it. inhibit viral spread.
“We are just at the top of the iceberg,” he said. “I think with a lot of companies there will be a lot of activity.”
While he noted that there was a big difference between having a powerful nanobode and a current drug, Seeger said he thought the new compound looked promising because it not only blocked the virus from attaching to cells, but actually altered spike protein conformation, locking down receptor binding domains that allow it to attach to cells.
The UCSF team members, who normally work in research such as deciphering the shape of receptors on cell membranes and understanding how proteins unfold, were thrown at the chance to work on coronavirus therapy in March. “When UCSF closed all research operations except coronavirus work, we stopped our regular and really run work,” Manglik said.
The project benefited from a massive library of synthetic yeast-produced nanobits that Manglik had helped create a few years ago, long before the pandemic, to better understand the structure of proteins to help design medicines and further basic research. . “The library would not have been there without the incentive for basic research,” Walter said.
It took Walter and his graduate student Michael Schoof to print Manglik to use the library to hunt for a coronavirus weapon. Manglik, who is also an MD, had recently started his lab at UCSF and said he saw the tools he was developing to engineer and optimize proteins for basic research as uniquely positioned “to directly address the number of pandemic deaths. “
They quickly examined the library’s 2 billion nanobit collection for what might work against the Covid-19 coronavirus using its peak protein to fish for the nanobodes associated with it. They then pulled that group into about 20 nanobodies that worked particularly well in preventing virus entry and cell infection. Aeronab 6 rose to the top because it bound to the peak protein in a really strong and unique way and because it was so stable. Walter, Manglik and Schoof hold a patent in the complex.
Although the nanobode worked well from the start, Manglik led an effort to optimize the molecule in order to be even more effective. The team created a version that both prevented the coronavirus spike proteins from binding to the cell and closed the points so that they remain in a position that makes them unavailable to bind. They also “humanized” the nanobode, so it closely resembled a human protein and thus would be less likely to elicit an allergic or immune response.
Manglik is not a fan of working with current bulbs; there are disasters and veterinary bills, not to mention the fact that it takes months to wait for an animal to produce nanobodys as they are infected with a pathogen. But he gives the animals a credit: “We have been dealing with the challenge of building molecules as beautiful as those produced in nature, and we take deep inspiration from the kind of antibodies that exist in camels, alpacas and llamas.”
He said the work was only possible due to the driving of many trainers on the project, some of whom worked routinely until 3 or 4 in the morning. The trainees, Manglik said, had no experience but gained it in enthusiasm and by “working to the limits of their physical ability”.
Those trained say they are inspired by Manglik’s willingness to work endless hours in the lab for routine bench work, even doing piracy during Zoom meetings. “Here is a full-fledged professor who comes in, shines and purifies proteins,” Schoof said.
UCSF scientists envision Aeronab 6 as something that can be offered to people who have recently tested positive for coronavirus to prevent disease progression. It can also be offered to people who have been exposed to the disease to prevent infection, or used as a daily prophylaxis for those at high risk of infection, such as healthcare workers, first responders and prison guards.