A new study by researchers at the University of Tübingen in Germany has revealed that sleep improves the ability of the immune cells to attach to their targets. The research explains how sleep can help to fight off an infection, while sleep deprivation makes the body more susceptible to illness.
T cells are critical to the body’s immune response. They recognize a specific target, such as a cell infected with a virus, and activate sticky proteins known as integrins that enable them to attach to their target and kill it if necessary.
The signals that activate integrins are well-documented, but the signals that inhibit the ability of T cells to attach to their targets are not clearly understood. For the current study, the team set out to investigate the effects of a diverse group of signaling molecules known as Gαs-coupled receptor agonists.
The study revealed that certain Gαs-coupled receptor agonists, including the hormones adrenaline and noradrenaline, prevented T cells from activating their integrins after recognizing their target.
“The levels of these molecules needed to inhibit integrin activation are observed in many pathological conditions, such as tumor growth, malaria infection, hypoxia, and stress,” said study lead author Stoyan Dimitrov. “This pathway may therefore contribute to the immune suppression associated with these pathologies.”
While the body is asleep, adrenaline levels decline. The researchers compared T cells taken from healthy volunteers after they had either slept or stayed awake all night. The T cells collected from those who slept showed significantly higher levels of integrin activation compared to T cells obtained from participants who did not sleep.
The researchers confirmed that the beneficial effect of sleep on T cell integrin activation was due to the decrease in Gαs-coupled receptor activation.
Study co-author Luciana Besedovsky said, “Our findings show that sleep has the potential to enhance the efficiency of T cell responses, which is especially relevant in light of the high prevalence of sleep disorders and conditions characterized by impaired sleep, such as depression, chronic stress, aging, and shift work.”
The research is published in the Journal of Experimental Medicine.