Importance of murine Vδ1+ γδ T cells expressing interferon-γ and interleukin-17A in innate protection against Listeria monocytogenes infection

Murine gamma delta T cells participate in the innate immune response against infection by an intracellular pathogen Listeria monocytogenes. V delta 1(+)gamma delta T cells coexpressing V gamma 6 are a major gamma delta T-cell subpopulation induced at an early stage of L. monocytogenes infection in the livers of infected mice. To investigate the protective role of the V gamma 6/V delta 1(+)gamma delta T cells against L. monocytogenes infection, V delta 1 gene-deficient (V delta 1(-/-)) mice were analysed because these mice selectively lacked a V gamma 6/V delta 1(+)gamma delta T-cell subpopulation in the L. monocytogenes-infected liver. The V delta 1(-/-) mice showed increased bacterial burden in the liver and spleen, and decreased survival rate at an early stage of L. monocytogenes infection when compared to wild-type mice. Histological examination showed abscess-like lesions and unorganized distribution of macrophages in the liver of the V delta 1(-/-) mice but not in the wild-type mice after L. monocytogenes infection. The V gamma 6/V delta 1(+)gamma delta T cells produced interferon-gamma and interleukin-17A. All the results suggest that murine V gamma 6/V delta 1(+)gamma delta T cells control the innate protective response against L. monocytogenes infection through production of the proinflammatory cytokines interferon-gamma and interleukin-17A in the infected liver.