Granulysin-dependent killing of intracellular and extracellular Mycobacterium tuberculosis by V gamma 9/V delta 2 T lymphocytes

Contribution of V gamma9/V delta2 T lymphocytes to immune protection agains t Mycobacterium tuberculosis is still a matter of debate. It was reported e arlier that V gamma9/V delta2 T lymphocytes kill macrophages harboring live M. tuberculosis through a granule-dependent mechanism that results in kill ing of intracellular bacilli. This study found that V gamma9/V delta2 T lym phocytes reduce the viability of both extracellular and intracellular M. tu berculosis. Granulysin and perforin, both detected in V gamma9/V delta2 T l ymphocytes, play a major role, which indicates that V gamma9/V deltaT lymph ocytes directly contribute to a protective host response against M. tubercu losis infection.