Esophageal cancer-derived microvesicles induce regulatory B cells.

The role of B cells in the generation of cancer-immune tolerance is unclear. This study aims to investigate the role of cancer-derived microvesicles (Mvcs) in the generation of transforming growth factor (TGF)-β(+) B cells. In this study, esophageal cancer (Eca) cells were isolated from surgically removed cancer tissue. Mvcs were purified from the culture supernatant and characterized by Western blotting. The immune suppression assay was carried out with a cell culture model and flow cytometry. The results showed that Eca-derived Mvcs were LAMP1 positive and carried MMP9. Exposure to the Mvcs induces naive B cells to differentiate into TGF-β-producing regulatory B cells; the latter show immune suppressor functions on CD8(+) T-cell proliferation. In conclusion, Eca-derived Mvc can induce TGF-β(+) B cells; the latter suppress CD8(+) T-cell activities. The MMP9-laden Mvcs may be a new therapeutic target in the treatment of Eca.