A groundbreaking study conducted by scientists at the Karolinska Institute (Sweden) has shed light on the effects of weightlessness on the immune system, in particular on T cells. The results of the study, published in the journal Science Advances, provide insight into why astronauts’ T cells become less active and less effective in fighting infections during spaceflight.
Immune system struggles in space
As the reality of human missions to the Moon and Mars approaches, it is important to understand the health risks associated with space travel. One important issue is the impact of weightlessness on the immune system, as astronauts often experience changes that persist after returning to Earth. As a result of immune deficiencies, they become more susceptible to infections and reactivation of dormant viruses in the body.
To address this problem, researchers at the Karolinska Institute set out on a journey to find out how weightlessness affects T-cells, a vital component of the immune system. “If we want astronauts to have safe space flights, we need to understand how weightlessness affects their immune system and find ways to counteract any harmful changes,” explains Lisa Westerberg, lead researcher in the Department of Microbiology, Tumor and Cell Biology.
Simulating weightlessness using dry immersion
In their quest for answers, the researchers used a technique called dry immersion to simulate weightlessness in space. Participants in the experiment were kept in a specially made water bed that forces the body to perceive weightlessness. Blood samples were taken from eight healthy people before the experiment began, on days 7, 14 and 21 of the simulation and 7 days after the experiment ended.
Effect of weightlessness on T cells
The study revealed significant changes in T-cell gene expression after 7 and 14 days of weightlessness simulation. The cells became more immature in their genetic program and resembled “naive” T cells that had not yet encountered intruders. This change suggests that the cells may take longer to activate, making them less effective in fighting tumor cells and infections.
Carlos Gallardo Dodd, a graduate student involved in the study, emphasizes the potential significance of these findings, “Our results may pave the way for new therapies that reverse these changes in the genetic program of immune cells.” The researchers also found that after 21 days, the T cells adapted their gene expression to weightlessness, almost returning to normal. However, seven days after the end of the experiment, some of the changes reappeared.
Future research
Based on these groundbreaking results, the scientists plan to conduct further studies using the Esrange Space Center’s probe rocket in Kiruna, Sweden. This platform will allow them to study how T cells behave in weightlessness and how this affects their function.
The study was conducted in close collaboration with Claudia Kutter’s research group at Karolinska Institutet/SciLifeLab, as well as with colleagues at IBMP in Moscow and New York University in Abu Dhabi.
