Changes of T lymphocyte subsets in mice immunized with recombinant Bb-Em Ⅱ/3-Em14-3-3 vaccine of Echinococcus multilocularis / 中华地方病学杂志

ABSTRACT

Objective In order to investigate the changes of T lymphocytes subsets in mice immunized with recombinant Bb-Em Ⅱ/3-Em14-3-3.vaccine of Echinococcus multilocularis (Em) and challenged with Em protoscoleces.Methods BALB/c mice were immunized with recombinant Bb-Em Ⅱ/3-Em14-3-3 vaccine by subcutaneous injection,intramuscular injection,nasal mucosa inoculation and oral administration,Bifidobacterium (Bb) and PBS were used as controls.After 12 weeks of immunization,all the mice were challenged with 50 protoscoleces of Em by intraperitoneal injection.Eighteen weeks later,mice were killed to measure alveolar hydatid weight and spleens were taken to separate spenocytes,in which the percentages of CD4+ and CD8+ T cell subsets were determined by flow cytometry.Results Alveolar hydatid weight was (0.77 ± 0.52),(0.87 ± 0.60),(2.17 ± 0.50),(3.06 ± 0.15) g in subcutaneous injection,intramuscular injection,nasal mucosa inoculation and oral administration groups,respectively,which was obviously lower than that in PBS control group [(3.54 ± 0.32) g,P ＜ 0.05 or ＜ 0.01].The level of CD49 T cell subset was (28.2 ± 2.5)％,(25.0 ± 2.7)％,(24.0 ± 1.3)％,(23.0 ± 1.8)％ in subcutaneous injection,intramuscular injection,nasal mucosa inoculation and oral administration groups,respectively,which was significantly higher than that in PBS control group [(16.1 ± 2.2)％,all P ＜ 0.01].The level of CD8+ T cell subset in the immunization groups was slightly elevated,but there was no statistical significance between groups (F =1.36,P ＞0.05).The level of CD4 + T cell subset in subcutaneous injection group was higher than that in intramuscular injection,nasal mucosa inoculation and oral administration groups (all P ＜ 0.05).Conclusion CD4+ T cell subset may play an important role in the protection of mice induced by recombinant Bb-Em Ⅱ/3-Em14-3-3 vaccine and the subcutaneous injection route appears to be a better way for immunization.