Several types of monoclonal antibodies are now in clinical trials. If all goes well, such concoctions might not only treat coronavirus infections but also prevent them. That could help millions of people, especially as the world awaits a vaccine, said Akiko Iwasaki, an immunologist at Yale University who was not involved in the study.
Studies like these could help researchers identify ideal antibody targets on the spike, Dr. Taylor said. Some pieces of the protein, for instance, will never mutate successfully because they are essential to the virus’s ability to break into cells. That makes them easy prey for the immune system.
But the new findings also hint that single-antibody formulations “may not be as successful,” Dr. Taylor said, at least in the long term. Developing a cocktail containing a diverse blend of antibodies could be a safer bet.
Such mixtures would also more accurately mimic the body’s natural response to the coronavirus. In the study, viruses flushed with samples of convalescent plasma — fractions of blood donated by people who have recovered from Covid-19 — struggled to infect cells.
Some scientists, including those at American biotechnology company Regeneron, are already attempting this combo approach, mixing two potent types of monoclonal antibodies into a single treatment.
But Dr. Iwasaki pointed out that antibody cocktails might be tougher to bring to market. “Every time you make a drug, you get approval for each component separately,” she said. Even so, the data so far indicates that “you don’t need hundreds of monoclonals” to subdue this virus, she added. Two might be plenty.
The lesson of diversity might be even more powerful for vaccines, which can marshal a multifaceted immune response. Some immune cells and molecules will be tailored to home in on the spike, whereas others might prefer other parts of the virus. Vaccines that present the body with many pieces of the coronavirus, rather than the spike alone, could have a better shot at triggering a suite of these defenses, said Dr. Taia Wang, an immunologist at Stanford University who was not involved in the study.