Abstrato

Dynamic Monitor on Immunologic Protective Mechanism in Mice Induced by Recombinant Echinococcus granulosus p-29 Protein (Reg.P-29)

Shuqin Ding, Yuanyuan Yang, Zhiyun Shi, Le Guo, Xueqin Ma and Wei Zhao

Echinococcosis is a worldwide lethal zoonotic infection caused by cestodes species of the genus Echinococcus. Echinococcus granulosus (Eg) antigens have been proved to possess protective immunity against secondary infection. In the present study, a diagnostic antigen P-29 was recombined, expressed and purified. There combining Eg.P-29(rEg. P-29) as a vaccine candidate was used to immunize mice, and the immune protection and mechanism of this protection was analyzed. Three groups of female mice, group A, B, and C were immunized intraperitoneally with rEg P-29 with complete Freund adjuvant (CFA) in PBS, or phosphate buffered saline (PBS), respectively. Two weeks after additional two boosters, mice were challenged with 2000 Eg protoscoleces (PSCs) intraperitoneally. Serum samples and spleens were collected from mice at different time point by sacrificing 5 mice in each group. Antibodies in serum and cytokines in supernatant of lymphocytes cultures were measured. The results showed that compared to control groups, mice immunized with rEg P-29 showed that the level of IgG, IgG1, IgG3 and IgG2b as well as IL-2, IL-4 and IFN-γ were significantly increased after one or more times of immunization, but neither IgG2a nor IgE did. Nevertheless, after mice inoculated with rEg.P-29 was challenged, CD4 + and CD8 + subsets significantly enhanced which implied that CD4 + and CD8 + subsets could enlist the protective immune mechanism (P<0.05). Therefore, as a promising candidate for an effective vaccine to prevent secondary Echinococcosis, protection against Eg protoscoleces induced with rEg.P-29 was associated with humoral and Th1 cellular responses.