How T Cells Change as a Result of Weightlessness Revealed in New Study

Findings from a new study from researchers at the Karolinska Institutet in Sweden could provide insights into the reduced activity and effectiveness of astronauts' T cells in fighting infections during space missions.

As humanity prepares for ambitious lunar and Mars missions, the hostile space environment raises significant health challenges, including alterations to the immune system. These changes persist even after astronauts return to Earth, leaving them more susceptible to infections and reactivation of latent viruses.

To comprehend these immune shifts, the team, led by Lisa Westerberg, senior author of the related paper published in Science Advances, simulated weightlessness by immersing volunteers in a custom waterbed to mimic a weightless state. Over three weeks, they monitored the gene expression of T cells in the blood of eight healthy individuals.

The study revealed significant gene expression changes in T cells after 7 and 14 days of simulated weightlessness, leading to a more immature genetic program. This shift made the T cells resemble "naïve" T cells, which might take longer to activate and be less effective against infections and tumors.

While T cell gene expression nearly returned to normal after 21 days, some changes persisted even after the experiment ended. To further investigate this phenomenon, the researchers plan to use the Esrange Space Centre's sounding rocket platform in Kiruna, Sweden, to study T cell behavior and function under weightless conditions.