“We said, ‘well this is weird,’” says Jones. “These cells need lots of energy. So, what are they using to make [it]?”He and his colleagues collected data from three other studies that genetically analysed T cells responding to infections and tumours. They found that, compared with dysfunctional T cells, effective T cells had increased activity in genes involved in breaking down ketones, indicating that they derived energy from ketones when fighting disease.
Next, the researchers genetically engineered three mice so that they couldn’t break down ketones and compared their response to an infection with an equal number of mice that could. They found that, on average, the normal mice had 50 per cent more T cells producing substances to kill off pathogens, called cytokines, than the engineered animals, and that these animals could churn out more cytokines per T cell as well. In other words, the ability to break down ketones made T cells more effective at fighting off infections in mice. Or, as Jones says, it increased the number of soldiers and ammunition on the front line.
Together, these findings suggest that immune cells are more effective at fighting disease when using ketones rather than glucose for fuel, says Jones. They also explain why previous research has shown that fasting for 12 or more hours daily improves immune function in mice, saysAdditionally, the results could help us understand how