Impact of Echinococcus granulosus Antigens on Monocyte Development and Dendritic Cell Differentiation.

Background: Different subtypes of dendritic cells (DCs) can induce different types of immune responses. Our previous study found that Echinococcus granulosus (E. granulosus) antigens (Eg.ferritin, Eg.mMDH and Eg.10) stimulated DC differentiation to different subtypes and produced different immune responses.

Objective: To further understand whether Eg.ferritin, Eg.mMDH and Eg.10 affect the DC-mediated immune response by promoting the differentiation of monocytes to DCs.

Methods: Bone marrow-derived monocytes were exposed to three antigens of E. granulosus on days 0, 3, 5, and 7. The percentage of monocyte-derived DCs (moDCs), DCs subsets, and the expression of surface molecules of DCs at different time points in different groups were assessed by flow cytometry. The levels of cytokines of IL-1β, IL-4, IL-6, IL-10, IL-13, IFN-γ, TNF-α, IL-12p70, IL-18, IL-23, and IL-27 in the cell culture supernatant were detected by multi-factorial detection technology.

Results: The percentage of moDCs revealed that none of the three antigens blocked monocyte differentiation to DCs. The monocytes of 7-day-old cultures showed increased sensitivity to these antigens. The Eg.ferritin induced more mature DCs, which expressed high levels of MHC II and costimulatory molecules, and secreted Th1 cytokines. Eg10 and Eg.mMDH induced lower degrees of DC maturation, however differentiated DCs were in a semi-mature state due to low expression of MHC II and costimulatory molecules and secretion of higher Th2 and lower Th1 cytokines.

Conclusion: Eg.ferritin promotes full maturation of DCs and induces Th1 immune response, whereas Eg.10 and Eg.mMDH induce semi-mature DCs producing higher levels of Th2 cytokines.