Prediction and identification of epitopes in the Echinococcus multilocularis thrombospondin 3 antigen

Immunoprotective effect and mechanism of rEg.P29 against CD4 + T cell-deficient mice with Echinococcus multilocularis infection

Alveolar echinococcosis (AE) is a zoonotic parasitic disease caused by infection with the larval stage of Echinococcus multilocularis and a major challenge to human public health. Vaccines are the most effective way to prevent and control infectious diseases. We previously revealed that the Echinocuccus granulosus recombinant protein P29 is a good vaccine candidate against E. granulosus. However, the protective and immunological mechanism of rEg.P29 against E. multilocularis remain unclear. In this study, CD4 + T cell-deficient mice are transferred with spleen CD4 + T cells isolated from wild-type mice and subjected to rEg.P29 immunization, and then these immunized mice are infected with E. multilocularis. The cyst inhibition rate is calculated by weighing the body and cyst weights. The level of antibody is detected by ELISA. Flow cytometry is used to detect the level of IFN-γ production by CD4 + T and CD8 + T cells. The cytokines in culture supernatant are detected by ELISA. The expressions of CD44 and CD62L on memory T cells are determined by flow cytometry. The results show the cyst inhibition rate is 41.52% after adoptive transfer of CD4 + T cells. Furthermore, the levels of IgG, IgM, IgA and IgE in serum are significantly increased compared with those in the PBS group. The IFN-γ-secretion by CD8 + T cells and the level of IFN-γ in culture supernatant are obviously increased; and the number of CD4 + T cells is increased, but the number of IFN-γ producing CD4 + T cells has no significant difference compared with PBS group. In addition, the number of CD44 +CD62L ‒CD8 + memory T cells in the spleen is significantly increased, while the number of CD44 ‒CD62L + CD8 + memory T cells is not significantly altered. Collectively, rEg.P29 can alleviate E. multilocularis infection by inducing humoral immune responses and CD8 + T cell responses.

A Bioengineered Nanovesicle Vaccine Boosts T-B cell Interaction for Immunotherapy of Echinococcus multilocularis

Alveolar echinococcosis (AE) is a zoonotic parasitic disease, resulting from being infected with the metacestode larvae of the tapeworm Echinococcus multilocularis (E. multilocularis). Novel prophylactic and therapeutic interventions are urgently needed since the current chemotherapy displays limited efficiency in AE treatment. Bioengineered nano cellular membrane vesicles are widely used for displaying the native conformational epitope peptides because of their unique structure and biocompatibility. In this study, four T-cells and four B-cells dominant epitope peptides of E. multilocularis with high immunogenicity were engineered into the Vero cell surface to construct a membrane vesicle nanovaccine for the treatment of AE. The results showed that the nanovesicle vaccine can efficiently activate dendritic cells, induce specific T/B cells to form a mutually activated circuit, and inhibit E. multilocularis infection. This study presents for the first time a nanovaccine strategy that can completely eliminate the burden of E. multilocularis.

Therapeutic effect on Alveolar echinococcosis by targeting EM-Leucine aminopeptidase

Alveolar echinococcosis (AE) is a parasitic disease caused by E. multilocularis metacestodes and it is highly prevalent in the northern hemisphere. We have previously found that vaccination with E. multilocularis Leucine aminopeptidase (EM-LAP) induced specific immune response and had an inhibiting effect on the parasites. In this study, the therapeutic effect of recombinant EM-LAP (rEM-LAP) on AE was evaluated and verified using Ubenimex, a broad-spectrum inhibitor of LAP. The results reveal that rEM-LAP could inhibit cyst growth and invasion and induce specific immunity response in BALB/c mice infected with E. multilocularis protoscoleces. The ultrasonic, MRI, and morphological results show that treatment with rEM-LAP inhibits E. multilocularis infection and reduces cyst weight, number, fibrosis and invasion. The same effect is observed for the treatment with Ubenimex by inhibiting LAP activity. The indirect ELISA shows that rEM-LAP could induce specific immunity response and produce high levels of IgG, IgG1, IgG2a, IgM, and IgA, and the serum levels of IFN-γ and IL-4 are significantly increased compared to the control groups, indicating that treatment with rEM-LAP leads to a Th1 and Th2 mixed-type immune response. This study suggests that EM-LAP could be a potential therapeutic target of E. multilocularis infection.