The dynamic observation on splenocyte cytokines in mice immunized with the transgenic alfalfa containing Eg95-EgA31 fusion gene of Echinococcus granulosus

Abstract

Objective To investigate the dynamic changes of splenocyte cytokines in mice immunized with the transgenic alfalfa containing Eg95-EgA31 fusion gene of Echinococcus granulosus (Eg). Methods Eighty-eight Balb/c mice were divided into 2 groups randomly according to body weights,and immunized orally or intranasally with 100μl or 10μl extracted leaf protein from the transgenic alfalfa(20 g/L) respectively once per 3 days for 2 months. Four mice randomized from each group were killed to get splenocyte on week 0(control),2,4,6,8,10,12,14,16,18 and 20 after the last immunization. The splenocyte were cultured in medium for 48 hours with EgAg or concanavalin A (ConA) stimulation to induce the interleukin (IL)-12,interferon γ(IFN-γ) and IL-10,and cultured for 72 hours with EgAg or lipopolysaccharide (LPS) stimulus to induce the tumor necrosis factor α (TNF-α). Then the supernatant was collected to measure the level of IL-12,IFN-γ,TNF-α and IL-10 by ELISA. Results In the oral immunization group,the level of IL-12,IFN-γ,TNF-α and IL-10 increased significantly from week 4 to week 6,week 2 to week 8,week 2 to week 6 and week 4 to week 12,respectively,reaching the highest level(25.0±5.8)ng/L on week 4,(575.0±28.9)ng/L on week 2,(50.0±11.5)ng/L on week 2 and (42.5±2.9)ng/L on week 8,respectively,as compared with the values on week 0[(11.3±2.5),(125.0±28.9),(11.3±2.5),(12.5±2.9)ng/L,all P < 0.01]; in the intranasal immunization group,it was similar about the values of IL-12,IFN-γ,TNF-α and IL-10 could be seen from week 4 to week 6,week 2 to week 10,week 4 to week 10 and week 6 to week 16,respectively,reaching the highest level(25.0±5.8)ng/L on week 6,(725.0±28.9)ng/L on week 4,(27.5±2.9)ng/L on week 6 and (60.0±11.5)ng/L on week 6,respectively,as compared with the values on week 0[(11.3±2.5),(125.0±28.9),(11.3±2.5),(12.5±2.9)ng/L,all P < 0.01]. The cytokine levels in the groups with EgAg,ConA or LPS stimulus were significantly higher than those in the corresponding splenocyte suspension groups(P < 0.05 or < 0.01),and the cytokine levels in the groups with ConA or LPS stimulus were obviously higher than those in the corresponding groups with EgAg stimulation (P < 0.05 or < 0.01). Conclusion The mixed responses of Th1 and Th2 types can be induced in mice immunized with the transgenic alfalfa in the early period post immunization(2-10 weeks). Key words: Echinococcus granulosus; Plants,genetically modified; Medicago sativa; Cytokines