SpaceX, an aerospace manufacturing company currently providing satellite launch services as well as transport of crew to the International Space Station, collaborated with researchers from MIT to monitor the spread of COVID amongst its employees.
Unusually, the paper included SpaceX CEO Elon Musk as a byline author. The technology entrepreneur is known to be quite hands-on in his company’s projects. However, he has also courted controversy by openly questioning COVID tests and saying he and his family would not take COVID vaccines, saying that achieving herd immunity naturally was a better strategy.
SpaceX was seeking data-driven methods to safeguard its essential workforce. The collaboration allowed the researchers to track the emergence of mild and asymptomatic cases in a cohort of adults as early as April, when data for such cases were rare.
“Essentially, this study indicates that it’s not simply the presence or absence of antibodies that matter; rather, the amount and type of antibodies may play a defining role in the development of a protective immune response,” said Professor Galit Alter, Harvard Medical School and Immunologist, Division of Infectious Diseases, Massachusetts General Hospital.
The study was originally aimed at measuring antibody levels over time, but when reinfections began to be reported, the team realised their samples had some valuable information.
“In early spring, we weren’t sure if asymptomatic infection could drive long-lived antibodies,” said Prof Alter, “nor whether they possessed the capability to neutralise or kill the virus.”
The researchers knew that 120 participants had mild or asymptomatic COVID infections, resulting in their bodies producing antibodies. Using sophisticated techniques to analyse those antibodies, they found that individuals with stronger symptoms in mild COVID, had a larger number of antibodies and developed immune functions associated with natural immune protection.
The study found that although the presence of antibodies was sufficient to determine whether an individual had experienced a COVID infection, they did not automatically mean that individual is protected against the virus in the long term.
Antibody effector functions (on the ‘long arm’ of the antibody) linked to long-term protection, such as T cell activation and virus neutralisation were only seen in certain immune responses. These involved high levels of antibodies targetting a part of the virus known as the receptor binding domain.
“Once you hit a certain threshold of these antibodies, it’s like a switch turns on and we can observe antibody effector functions,” said first author Yannic Bartsch, PhD. “These functions were not observed in individuals with lower antibody binding titers, and the level of protection from reinfections is uncertain in these individuals.”
Source: News-Medical.Net
Journal information: Bartsch, Y. C., et al. (2021) Discrete SARS-CoV-2 antibody titers track with functional humoral stability. Nature Communications. doi.org/10.1038/s41467-021-21336-8.
