Activation of human V gamma 9V delta 2 T cells by a Brucella suis non-peptidic fraction impairs bacterial intracellular multiplication in monocytic infected cells

Human gamma delta T cells are considered to play an important role in the e arly response to infection with intracellular pathogens. Evidence has been presented that the percentage of gamma delta T cells with V gamma 9V delta 2 phenotype is dramatically increased in the peripheral blood of patients w ith acute brucellosis. This specific gamma delta T-cell subpopulation is kn own to be activated by small non-peptidic molecules that can either be prod uced by the pathogen itself or released from damaged cells after infection. In the present work we provide evidence that V gamma 9V delta 2 T lymphocy tes from peripheral blood mononuclear cells of healthy donors can be specif ically activated by non-peptidic low-molecular-weight compound(s) from Bruc ella suis lysate. Moreover, we show that V gamma 9V delta 2 T cells activat ed by this B. suis fraction produce tumour necrosis factor-alpha and interf eron-gamma, which reduce bacterial multiplication inside infected cells.