ABSTRACT
Objective To investigate the change of splenocyte subsets in Balb/c mice immunized with transgenic alfalfa(Medicago sativa)containing Eg95-EgA31 fusion gene of Echinococcus granulosus(Eg) and challenged with Eg protoscoleces.Methods Leaf protein was extracted from transgenic alfalfa containing Eg95-EgA31 fusion gene by heat-coagulation method,and concentration of 20 g/L was used in the study.Meanwhile,leaf protein extracted from the transgenic alfalfa containing blank vector(pBI121)and the normal alfalfa was served as control.Thirty-two female Balb/c mice were randomly divided into 4 groups,8 mice in each group.Oral group was immunized with the leaf protein containing Eg95-EgA31 fusion antigen intragastrically(100μl per mouse);intranasal group was immunized with the leaf protein containing Eg95-EgA31 fusion antigen intranasally(10 μl per mouse);blank vector group was vaccinated intranasally with 10μl leaf protein with blank vector(pBI121);and normal control group was given 100μl normal leaf protein intragastrically.All mice in the above mentioned groups were immunized every 3 days for 2 months.Then,the mice were challenged intraperitoneally with Eg protoscoleces(50 protoscoleces per mouse)8 weeks after last vaccination and sacrified 24 weeks pest infection to separate the splenocytes.Flow cytometry was used to measure the percentages of CD4+ and CD8+ T ceils subsets.Resuits Compared with the normal control group(0.166±0.018,0.083±0.006,2.019 ±0.369),the percentages of CD4+(0.286±0.009)and CD8+(0.102±0.004)T cell subsets and the ratio of CD4+/CD8+(2.814±0.014)in oral group increased significantly (P<0.01 or<0.05).The percentage of CD4+ subset(0.269±0.016)and the ratio of CD4+/CD8+(2.955±0.986) in intranasal group was significantly higher than that ofthe normal control group(all P<0.01).The percentage of CD4+ subset in oral group was significantly higher than that of the intranasal group(P<0.05).No significant difference was found in the percentages of CD4+ and CD8+ T cell subsets and the ratio of CD4+/CD8+ between the blank vector group(0.169±0.018,0.093±0.019,1.852±0.188)and the normal control group(all P>0.05).Conclusions CD4+ T cell may play an important role in the protection induced by transgenic alfalfa vaccine against the challenge of Eg protoscoleces.Intragastrical immunization may be a good route.
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).
ABSTRACT
Objective To cultivate and identify the transgenic affalfa containing Echinococcus granulosus Eg95 gene. Methods The alfalfa plants were transformed by co-cultivating alfalfa cotyledons via recombinant Agrobacterium tumefaciens LBA4404 harboring pBI-Eg95. The transgenic alfalfa explants were selected by kanamyein after calli formation, shoots and roots regeneration in the selective medium, the seedlings of transgenic plants were obtained which were finally transplanted into pots containing nutrient soil. After 2-3 months growth, the complete transgenic alfalfa plants containing Echinococcus granulosus Eg95 gene were obtained. To identify the transgenic alfalfa plants, the total DNA, RNA and leaf protein were extracted from fresh leaf tissue of the transgenic alfalfa plants and confirmed by PCR, RT-PCR, SDS-PAGE and Western blot assay. Results A specific band around 471 bp was amplified by PCR with total DNA, and the same band was obtained by RT-PCR with total RNA, which confirmed that the Eg95 gene was stably integrated into the transformed alfalfa genome. SDS-PAGE analysis showed that the relative molecular mass(Mr) of the expressed protein was about 16.5×103, consistent with the Eg95 protein, and the level of Eg95 expression was up to 0.06% of total soluble leaf protein by Bio-Rad Quantity one assay. Western blot verified the expressed protein was reactive with the sera of mice infected with Echinococcus granulosus. Conclusion The transgenic alfalfa plants containing Echinococcus granulosus Eg95 gene are successfully cultivated.
