Effects of epidermal growth factor receptor fusion protein on the cytotoxic activity of SOCS1-silenced dendritic cells in vitro

The aim of the present study was to observe the effects of cytokine signaling suppressor 1 (SOCS1)-silenced dendritic cells (DCs) pulsed with epidermal growth factor receptor (EGFR) fusion protein on the activation of T lymphocyte and cytotoxic T-lymphocyte (CTL) activity against Hep-2 cells. DCs were derived from the medullary cells of mice and authenticated by flow cytometry (FCM). Recombinant glutathione-S-transferase (GST)-EGFR fusion protein was produced and purified. After being pulsed with it, DCs were modified by recombinant SOCS1-siRNA adenoviral to silence SOCS1 gene expression. The maturation of DCs was evaluated by FCM. The effects of modified DCs on T-cell proliferation were assessed by MTT assay. The killing effects against Hep-2 cells of CTL were assessed by lactate dehydrogenase (LDH) release assay. High-purity DCs from the medullary cells of mice were obtained. Compared with the control, EGFR-pulsed DCs displayed higher expression of cell surface molecules, including CD83, CD860 and HLA-DR. The MTT assay revealed that all of the EGFR-pulsed, SOCS1‑silenced and EGFR-pulsed plus SOCS1-silenced DCs had an enhanced capacity to stimulate T-lymphocyte proliferation. As expected, EGFR-pulsed plus SOCS1-silenced DCs had the strongest effects on T-cell proliferation. The splenic T cells isolated from both EGFR-pulsed DC-immunized mice and EGFR-pulsed plus SOCS1-silenced DC-immunized mice enhanced the cytotoxicity against Hep-2 cells, while T cells from EGFR‑pulsed plus SOCS1-silenced DC-immunized mice exhibited significantly higher cytotoxicity than those from EGFR-DC-immunized mice. The EGFR-pulsed SOCS1‑siRNA-silenced DCs had the strongest effects on activation of T-cell proliferation and the CTL activity against Hep-2 cells.