In mice, the outcome of tuberculosis infection is influenced by how quickly bacteria-fighting T cells can get to the lungs.
According to a new study that will appear online on June 14th in the Journal of Experimental Medicine (www.jem.org), another group of T cells delays their arrival.
Previous research has shown that ridding the body of the hindering T cells—known as regulatory T cells—enhances the body's ability to fight off TB-causing bacteria. But exactly when and where regulatory T cells act was uncertain. The new study shows that these cells are activated at the same time and place as their bacteria-fighting "effector" cell counterparts. In response to infection, both populations expand in the lymph nodes that drain the lung. As a result, fewer effector T cells become activated and are dispatched to the lungs to fight the bug.