Abstract: Objective To investigate the level of cytokines in spleen from mice immunized with recombinant Bifidobacteria bifidum（Bb）-Eg95-EgA31 vaccine of Echinococcus granulosus（Eg） and challenged with Eg protoscoleces. Methods 56 female BALB/c mice were randomly divided into 7 groups: Recombinant Bb-Eg95-EgA31 vaccine subcutaneous injection （group A）， intramuscular injection （B）， intranasal immunization （C）， oral administration （D）， blank vector control （E）， Bb control （F） and MRS control （G）. Mice in all groups were challenged with 50 Eg protoscoleces on the 8th week after vaccination and sacrificed on the 25th week after infection. Spleens were collected to prepare splenocytes, which were cultured under activation of crude Eg antigen （EgAg）， with concanavalin A （ConA） or lipopolysaccharide （LPS） stimulation and non-stimulation as control. The splenocyte supernatants were collected to determine the levels of interferon-γ（IFN-γ）， interleukin-12 （IL-12）， tumour necrosis factor-α （TNF-α） and IL-10 by ELISA. Results The level of IFN-γ in groups A ［（137.5±23.2） pg/ml］， B ［（162.5±23.2） pg/ml］， C ［（250.0±53.5） pg/ml］ and D ［（215.0±37.4） pg/ml］ was higher than that of group G ［（50.0±10.7） pg/ml］ （P＜0.01）. The level of IL-12 in groups A ［（27.5±4.6） pg/ml］， B ［（32.5±4.6） pg/ml］， C ［（45.0±5.4） pg/ml］ and D ［（35.0±5.4） pg/ml］ was higher than that of group G ［（15.0±5.4） pg/ml］ （P＜0.01）. The level of TNF-α in groups A ［（275.0±46.3） pg/ml］， B ［（325.0±46.3） pg/ml］， C ［（450.0±53.5） pg/ml］ and D ［（350.0±53.5） pg/ml］ was higher than that of group G ［（150.0±53.5） pg/ml］ （P＜0.01）. The level of IL-10 in groups A ［（37.5±4.6） pg/ml］， B ［（35.0±5.4） pg/ml］， C ［（25.0±5.4） pg/ml］ and D ［（32.5±4.6） pg/ml］ was lower than that of group G ［（45.0±5.4） pg/ml］ （P＜0.05 or P＜0.01）. Conclusion The recombinant Bb-Eg95-EgA31 vaccine can induce a protective Th1 type immune response in mice.

Key words: Echinococcus granulosus, Recombinant Bb-Eg95-EgA31 vaccine, Cytokine