Objective To explore the dysfunction of dendritic cells (DC) related to TGFβ reversed after blocking the TGFβ signal pathway by recombinant adenovirus vector encoding for Smad7.Methods Smad7 by recombinant adenovirus vector was transfected into dendritic cells.Expression of immunologic phenotypes was detected by FCM,and CTL activity induced by DC was compared.Results The DC modified with Smad7 still expressed high adhesiveness factor related to maturation even if existing exogenous TGFβ1,which was significant statistically compared with DC transfected with control adenoviral vector (P <0.01).Even if existing exogenous TGFβ1,the DC modified with Smad7 pulsed with soluble antigen associated with Lewis pulmonary carcinoma could still induce potent CTL activity against Lewis pulmonary carcinoma,which showed significant difference with DC-Ad-c (P <0.01).Conclusion The inhibitory effects on function of DC of TGFβ may be reversed by blocking the Smad signal of TGFβ pathway. Key words: Dendritic cells; Transforming growth factor beta; Adenoviral vector; Smad7