PROTECTIVE ROLE OF GAMMA DELTA T-CELLS AND ALPHA/BETA T-CELLS IN TUBERCULOSIS/

Tuberculosis is a chronic infectious disease which causes major health problems globally. Although acquired resistance crucially depends on alpha/beta lymphocytes, circumstantial evidence suggests that, in addi tion, gamma/delta T lymphocytes contribute to protection against tuber culosis. We have studied Mycobacterium tuberculosis infection in TcR-d elta(-/-) or TcR-beta(-/-) gene deletion mutants which completely lack gamma/delta T cells or alpha/beta T cells, respectively. Low inocula of M. tuberculosis led to death of TcR-beta(-/-) mice and transient di sease exacerbation in TcR-delta(-/-) mutants. Infection with higher in ocula caused rapid death of TcR-delta(-/-) mice. The development of an d bacterial containment in granulomatous lesions was markedly impaired in TcR-beta(-/-), and less severly affected in TcR-delta(-/-) mutants . Mycobacteria-induced IFN-gamma production by spleen cells in vitro w as almost abolished in TcR-beta(-/-) and virtually unaffected in TcR-d elta(-/-) mice. Our data confirm the crucial role of alpha/beta T cell s in protection against established tuberculosis and formally prove a protective role of gamma/delta T cells in early tuberculosis.