What do we really know about how CD4 T cells control Mycobacterium tuberculosis?

The authors made the surprising observations that both mycobacteria-specific and non-specific CD4 T cell migrated vigorously through the granuloma, with very few antigen-specific T cells showing migration arrest, a hallmark of potent antigen recognition and presentation.\n As we cannot currently measure this effector function, other than by bacterial arrest, we cannot discount the possibility that the appropriate effector function is being expressed, but that it does not require significant migration arrest or cytokine production (Figure 1). [...]the key question is, how can this information improve control of tuberculosis?