Immune cells have a surprising role in exercise endurance

Immune cells that help to 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 ‘security guards’ of the immune system, identifying harmful pathogens and actively producing antibodies to target them, says Peng Jiang, an immunologist at Tsinghua University in Beijing and anthor of the study. But until now, the cells’ role in metabolism had not been observed. Jiang says this is the first time that a function for these cells that is not associated with the immune system has been described— “a finding completely beyond our initial expectations”, he says.

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

Run, run, run

Jiang’s team studied whether there was a connection between the immune system and exercise performance. They tested the endurance of mice that had been genetically modified to have a low B-cell count 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, which is used in humans to target cancer-causing B cells. The antibodies destroy any B cells that they come across.