Potential Role of Gr-1 < sup > + < /sup > CD8 < sup > + < /sup > T Lymphocytes as a Source of Interferon- γ and M1/M2 Polarization during the Acute Phase of Murine < b > < i > Legionella pneumophila < /i > < /b > Pneumonia
In this study, we analyzed interferon (IFN)- γ-producing cells and M1/M2 macrophage polarization inLegionella 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- γ in the acute phase, and anti-Gr-1 treatment reduced the number of IFN-γ-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- γ-producing Gr-1+ CD8+ T lymphocytes in the lungs and LNs increased 2 and 4 days afterL. pneumophila infection, with anti-Gr-1 treatment attenuating these populations. Antibody staining revealed that Gr-1+ CD8+ T lymphocytes were Ly6C-positive cells rather than Ly6G, a phenotype regarded as memory type cells. Furthermore, the adoptive transfer of Gr-1+ CD8+ T lymphocytes induced increases in IFN- γ, M1 shifting and reduced bacterial number in theLegionella pneumonia model. These data identified Ly6C+ CD8+ T lymphocytes as a source of IFN- γ in innate immunity and partially associated with reduced IFN-γ production, M2 polarization, and high mortality in anti-Gr-1 antibody-treated mice withL. pneumophila pneumonia.J Innate Immun
Source: Journal of Innate Immunity - Category: Allergy & Immunology Source Type: research