Gating strategy used to identify T cells, NK cells, and NKT cells isolated from human lung tissue. Lung tissue was dispersed and stained with CD45, CD3, CD8, CD4, and CD56 monoclonal antibodies to identify various cell subsets. (A) Viable CD45+ cells with a low side scatter profile were selected; (B) cells were further divided into CD3- and CD3+ fractions; (C) CD56+ cells were selected from the CD3- fraction and (E) NK cells were selected by excluding CD4 and CD8. (D) CD8+ and CD4+ cells were identified and (F) CD56+ was used to separate CD8+ NKT cells from CD8+ T cells and (G) CD4+ NKT cells from CD4+ T cells. Appropriate isotype-matched controls for all antibodies were used to determine positive staining.