Two Antibodies Capable of Neutralizing Alphaviruses Identified

Researchers at Washington University School of Medicine in St. Louis have identified two antibodies that protect animals from disease caused by alphaviruses. The findings were published in Cell.

To find antibodies that would protect against the whole alphavirus group, the team screened a set of antibodies produced by two people who had been infected with the chikungunya virus. They tested the antibodies against a panel of alphaviruses representing both branches of the group. Two antibodies recognized all of the alphaviruses tested. Then, they assessed whether the antibodies could prevent arthritis or brain infection in animals. Using mice, they tested each antibody against two alphaviruses that cause arthritis and three that cause brain infections. Both antibodies protected the animals against all of the viruses.

Further experiments showed that the antibodies worked by blocking developing virus particles from exiting one cell en route to infecting another. The antibodies attach to part of a viral protein called E1 that is exposed only during the exiting process. Once the virus has fully formed and detached from the cell, the E1 protein is folded into the virus particle and hidden.

“If we could figure out how to make a vaccine that targets the E1 protein effectively, it would be a cost-effective way to provide broad protection for people in resource-limited places, which is where most alphavirus infections occur,” lead researcher Michael Diamond said. “It’s challenging to make such a vaccine since the target is hidden most of the time. But there are techniques that can be used to make the immune system focus on E1 and generate a good antibody response against it. That’s the next step toward creating a universal vaccine.”