[Study on immune response in ICR mice by immunization with recombinant myophilin vaccine against Echinococcus granulosus].

Objective: To investigate the immune response and the protection in mice induced by the recombinant myophilin protein of Echinococcus granulosus.

Methods: Thirty-six male ICR mice of 6-8 weeks old were randomly divided into groups A, B and C each with 12. The mice in the 3 groups were subcutaneously immunized with Eg myophilin protein, blank plasmid protein or PBS, respectively, by 3 times and challenged with protoscoleces of E. granulosus 2wk after the last vaccination. Mice were sacrificed 20wk after the infection, the hydatid cysts were collected for measuring the weight reduction. Spleens were obtained and the splenocytes were separated and cultured in vitro with EgAg or ConA stimulus for 4-5 h. The subsets of CD4+ and CD8+ T cells were measured by FACsort. The proliferation of splenocytes was determined by MTT method with blank plasmid and PBS as control.

Results: The average weight of the hydatid cysts in the immunized group decreased by 69.1% in comparison to the blank plasmid and PBS groups. The CD4+ subset [(29.7 +/- 0.9)%] and CD84+ subset [(9.7 +/- 0.8)%] in group A increased significantly than group C, [(11.6 +/- 1.4)%] and [(7.8 +/- 0.2)%] respectively (P < 0.01 or < 0.05). The ratio of CD4+/CD8+ subsets in group A (3.061 +/- 0.015) was also higher than group C (1.487 +/- 0.106) (P < 0.01). Without stimulation, the proliferation of T lymphocytes in group A(0.237 +/- 0.009) was higher than group C (0.159 +/- 0.005) (P < 0.01), with EgAg or ConA stimulus, it was also higher in group A than that of group C (P < 0.01).

Conclusion: The recombinant myophilin protein of E. granulosus can induce the proliferation of splenocytes and Th1 response in mice, and the CD4+ T cells subset may bear a part in the induced protection against the challenge of protoscoleces.