The change of splenocyte subsets in Balb/c mice by immunization with the transgenic alfalfa(Medicago sativa) containing Eg95-EgA31 fusion gene of Echinococcus granulosus / 中国地方病学杂志

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.