ABSTRACT
<p><b>OBJECTIVE</b>To develop a novel vaccine by immobilizing interleukin-21 (IL-21) on the surface of MB49 cells and evaluate its effect in inducing specific cytotoxic T lymphocytes (CTLs) and antitumor immunity in a mouse model of subcutaneous metastatic bladder cancer.</p><p><b>METHODS</b>SA-IL-21 was immobilized on the surface of 30% ethanol-fixed MB49 cells to prepare the cell vaccine. C57BL/6 mice with subcutaneous implantation of MB49 bladder cancer cells were randomized into 5 groups to receive treatments with IL-21/MB49 vaccine, soluble IL-21, GFP surface-modified MB49 cells, ethanol-fixed MB49 cells, or PBS. The tumor growth and CTL were examined to assess the antitumor efficacy of the vaccine.</p><p><b>RESULTS</b>IL-21 surface-modified MB49 cell vaccine significantly inhibited the tumor growth and generated a long-lasting memory response (P<0.05). At the same effector-target (E:T) ratio, the specific CTLs induced by IL-21/MB49 vaccine showed the most potent cytotoxicity against MB49 cells (P<0.05).</p><p><b>CONCLUSION</b>With the protein-anchor technique, IL-21 can be efficiently immobilized on the surface of MB49 cells to prepare IL-21/MB49 cells vaccine. The novel vaccine can maintain its biological activity and significantly enhance the cytotoxicity of CTLs against bladder cancer cells.</p>