Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) for the initiation of antigen (Ag)-specific immune responses. In most studies, mature DCs are generated from bone marrow cells or peripheral monocytes; in either case, the harvested cells are then cultured in medium containing recombinant GM-CSF, IL-4 and TNF-α for 7-10 days and stimulated with lipopolysaccharide (LPS). However, this approach is time-consuming and expensive. There is another less cost approach of using immobilized DC cell lines, which can easily grow in the medium. A disadvantage with the immobilized DC cell lines, however, is that they are immature DCs and lack expression of MHC class Ⅱ and costimulatory CD40 and CD80 molecules. This, therefore, limits their capacity for inducing efficient antitumor immunity. In the current study, we investigated the possible efficacy of various stimuli (IL-1β,IFN-γ, TNF-α, CpG and LPS) in converting the immature dendritic cell line DC2.4 to mature DCs. Our findings were quite interesting since we demonstrated for the first time that IFN-γ was able to stimulate the maturation of DC2.4 cells. The IFN-γ-activated ovalbumin (OVA)-pulsed DC2.4 cells have capacity to upregulate MHC class Ⅱ,CD40, CD80 and CCR7, and to more efficiently stimulate in vitro and in vivo OVA-specific CD8+ T cell responses and antitumor immunity. Therefore, IFN-γ-activated immortal DC2.4 cells may prove to be useful in the study of DC biology and antitumor immunity.