Figure 4.

Circulating CD14⁺ HLA‐DR ⁻ cells from patients with squamous cell carcinoma of the head and neck (SCCHN) suppress autologous T‐cell proliferation and interferon (IFN)‐γ production. CD14⁺ HLA‐DR ⁻ and CD14⁺ HLA‐DR ⁺ cells were sorted from peripheral blood mononuclear cells of 10 patients with SCCHN and cultured with carboxyfluorescein succinimidyl ester (CFSE)‐labeled autologous T cells stimulated with anti‐CD3/anti‐CD28 stimulus. Proliferation of T cells was measured by dilution of CFSE staining intensity using flow cytometry. Representative data from one patient with SCCHN (A,B). CD14⁺ HLA‐DR ⁻ cells showed greater suppressor activity than CD14⁺ HLA‐DR ⁺ cells (T cell/CD14⁺ HLA‐DR ⁻ cell ratio, 2:1) (A), and inhibited the proliferation of autologous T cells in a dose‐dependent manner (B). IFN‐γ production from anti‐CD3/anti‐CD28‐stimulated T cells cocultured with CD14⁺ HLA‐DR ⁻ or CD14⁺ HLA‐DR ⁺ cells was measured using ELISA (T cell/CD14⁺ HLA‐DR ⁻ cell ratio, 4:1) (C).