Potential Role of Gr-1(+) CD8(+) T Lymphocytes as a Source of Interferon-gamma and M1/M2 Polarization during the Acute Phase of Murine Legionella pneumophila Pneumonia

摘要

In this study, we analyzed interferon (IFN)-gamma-producing cells and M1/M2 macrophage polarization in Legionella pneumophila pneumonia following anti-Gr-1 antibody treatment. Anti-Gr-1 treatment induced an M1-to-M2 shift of macrophage subtypes in the lungs and weakly in the peripheral blood, which was associated with increased mortality in legionella- infected mice. CD8(+) T lymphocytes and natural killer cells were the dominant sources of IFN-gamma in the acute phase, and anti-Gr-1 treatment reduced the number of IFN-gamma producing CD8(+) T lymphocytes. In the CD3-gated population, most Gr-1-positive cells were CD8(+) T lymphocytes in the lungs and lymph nodes (LNs) of infected mice. Additionally, the number of IFN-gamma-producing Gr-1+ CD8(+) T lymphocytes in the lungs and LNs increased 2 and 4 days after L. pneumophila infection, with anti-Gr-1 treatment attenuating these populations. Antibody staining revealed that Gr-Ly6G, a phenotype regarded as memory type cells. Furthermore, the adoptive transfer of Gr-1+ CD8(+) T lymphocytes induced increases in IFN-gamma, M1 shifting and reduced bacterial number in the Legionella pneumonia model. These data identified Ly6C+ CD8(+) T lymphocytes as a source of IFN-gamma in innate immunity and partially associated with reduced IFN-gamma production, M2 polarization, and high mortality in anti-Gr-1 antibody-treated mice with L. pneumophila pneumonia. (C) 2018 S. Karger AG, Basel