Immune cells have a surprising role in exercise endurance

Immune cells that help fight off foreign invaders in the body also provide crucial support for muscles during exercise, suggests a mouse study published in cell today¹.

B cells are the “guardians” of the immune system, identifying harmful pathogens and actively producing antibodies to target them, said Peng Jiang, an immunologist at Tsinghua University in Beijing and an author of the study. But until now, the role of cells in metabolism has not been observed. Jiang says this is the first time a function for these cells unrelated to the immune system has been described — “a finding completely beyond our initial expectations,” he says.

Carolyn Daniel, director of the Helmholtz Munich Institute for Metabolism and Immunology in Germany, says there is growing interest in studying the functions of B and T cells outside of the immune system. The finding that B cells can be crucial mediators between the immune system and organs involved in exercise is an important conceptual advance, she adds.

Run, run, run

Jiang’s team investigated whether there was a link between the immune system and exercise performance. They tested the endurance of mice that had been genetically engineered to have low B-cell counts by having them run on a treadmill. The researchers increased the speed at predetermined intervals over a period of about 15 minutes, stopping when the mouse became exhausted.

They repeated the experiment with another group of mice that they treated with an antibody therapy that is used in humans to target cancer-causing B cells. Antibodies destroy any B cells they encounter.