Objective: To examine the activation and cytotoxicity of human peripheral blood T lymphocyte induced in vitro by human 4-1-BB ligand (4-1-BBL) gene transfected into tumor Tca8113 cells.
Methods: The eukaryotic expression vector pEGFP-h4-1-BBL was transfected into human oral carcinoma cell line Tca8113 by Lipofectamine 2000. The transfected cells were then selected in medium containing G-418, cloned by limited dilution and named as Tca8113-4-1-BBL. Human 4-1-BBL mRNA and protein expression of transfected cells was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting respectively. The tumor cell vaccines (TCV) were obtained by treatment with mitomycin (MMC). Human peripheral blood mononuclear cells (PBMC) were prepared from lymphoprep, and then stimulated with anti-CD-3 mAb and incubated with non-transfected or transfected TCV-Tca8113 cells, respectively. The proliferation of T cells was evaluated by trypan blue exclusion; the CCK-8 was used to detect the cytotoxic effect of T lymphocytes. Meanwhile, the secretion of interferon-gamma (IFN-gamma) and interleukin (IL)-2 in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA).
Results: The Tca8113 cells transfected by pEGFP-h4-1-BBL could express human 4-1-BBL efficiently. As compared with wild type Tca8113 cells, the transfected Tca8113 cells could markedly promote proliferation, IL-2 and IFN-gamma production and cytotoxic activity of lymphocytes.
Conclusions: The transfection of human 4-1-BBL gene in Tca8113 cells is effective in enhancing its immunogenicity and inducing antitumor immune response in vitro.