Figure 6.

Suppressive mechanisms of CD14⁺ HLA‐DR ⁻ cells obtained from patients with squamous cell carcinoma of the head and neck (SCCHN). TGF‐β production from CD14⁺ HLA‐DR ⁻ and CD14⁺ HLA‐DR ⁺ cells. Bars indicate mean values derived from five independent patients (A). Supernatants from sorted CD14⁺ HLA‐DR ⁻ or CD14⁺ HLA‐DR ⁺ cells (5 × 10⁵ cells/mL) were collected after 24 h incubation at 37°C and cytokine concentrations were determined using ELISA. The role of CD86, PD‐L1 and TGF‐β in the suppressive function of CD14⁺ HLA‐DR ⁻ cells obtained from patients with SCCHN. Anti‐CD86 mAb, anti‐PD‐L1 mAb and anti‐TGF‐β neutralizing mAb were added for blocking experiments. Representative data from one patient with SCCHN (B: T‐cell proliferation; C: IFN‐γ production, T cell/CD14⁺ HLA‐DR ⁻ cell ratio, 4:1). The recovery rate of proliferated T cells by addition of anti‐CD86 mAb, anti‐PD‐L1 mAb and anti‐TGF‐β neutralizing mAb (D). Proliferation of T cells was measured by dilution of CFSE staining intensity using flow cytometry. Data are the mean of five independent patients.