An international team of researchers has identified antibodies that could be used as preventative treatment for COVID-19.

The team, led by Davide Corti of Vir Biotechnology and University of Washington professor David Veesler, involves several UC Berkeley researchers. Its research found that one specific antibody, S309, can be used to neutralize the coronavirus and effectively prevent it from entering human cells.

Julia Schaletzky, executive director of the UC Berkeley Center for Emerging and Neglected Diseases, described how the coronavirus works using an analogy. She said the crownlike spikes, or spike glycoproteins, on the outside of the virus allow it to get into human cells, acting like a key in a lock.

“It’s like you’re selling a house and the virus knocks on the door,” Schaletzky said. “Normally it can’t get in, but if you have the right receptor protein, the virus comes in.”

The virus then hijacks the host cell and makes thousands of copies of itself with its genetic blueprint, or RNA, according to Schaletzky. The peer-reviewed study found that S309 binds to the spike protein and prevents it from interacting with the receptor. Therefore, it prevents the COVID-19 virus from ever entering a human cell. Researchers looked at SARS antibodies and found S309. According to Schaletzky, SARS is similar to the COVID-19 virus, which is also known as SARS-CoV-2.

To better understand how S309 works, the team turned to cryo-electron microscopy at the University of Washington and X-ray crystallography performed at an Advanced Light Source beamline managed by the Berkeley Center for Structural Biology, or BCSB, a science division at Lawrence Berkeley National Laboratory.

Schaletzky described cryo-electron microscopy as similar to the human mind, in that when we see pictures of something from multiple angles, we can often mentally construct a 3D image of the object.

“The researchers used the beamline to identify the 3D structure and molecular details of the antibody,” said head of BCSB Marc Allaire in an email. “Our specialized protein crystallography beamline provided diffraction data from crystals of the neutralizing antibody. Further analysis of that data allowed them to examine interactions between this neutralizing antibody and the SARS-CoV-2 spike proteins.”

According to the paper, variants of S309 are on an accelerated development track to clinical trials.

Lee Riley, campus professor and chair of the division of infectious diseases and vaccinology, said this finding could potentially be used to prevent people from contracting the coronavirus or to treat its very early infection period.

“This antibody is directed at one particular part of the virus, but once the virus gets into the cells, the antibodies can’t do anything,” Riley said. “If someone has a severe disease, it means the virus has already gotten into the cells. So the virus is no longer doing damage, it’s your own immune system.”