Up-regulation of MDSCs accumulation and Th2 biased response to co-stimulation of CsESP from Clonorchis sinensis and HBeAg in vitro

Co-infection with Clonorchis sinensis (C. sinensis) and Hepatitis B virus (HBV) are commonly observed in endemic areas of Clonorchiasis. Chronic infection of C. sinensis or HBV is more likely to happen. However, the immune mechanisms related to the pathogenesis of co-infection remain unknown. In the present study, Myeloid-derived suppressor cells (MDSCs) accumulation, bone marrow derived dendritic cells (BMDCs) reaction and the consequent effectors on Th1/Th2 polarization to co-incubation of excretory-secretory products from C. sinensis (CsESP) and Hepatitis B e antigen (HBeAg) in vitro were investigated for further understanding the immune response during co-infection. The results indicated that compared with CsESP or HBeAg alone, co-stimulation dominantly promoted MDSCs accumulation. Co-stimulation significantly downregulated the expression of CD80 and CD86, and reduced IL-12p70 release while augmented IL-10 levels of BMDCs. Higher transcription levels of mannose receptor (MR) while lower mRNA level of toll like receptor 4 (TLR-4) were detected among membrane receptors of BMDCs with co-treatment. In addition, after CD4 naïve T cells were stimulated by LPS-treated BMDCs with CsESP and HBeAg, the proportion of CD4⁺IL-4⁺ T cells and IL-4 increased, while CD4⁺INF-γ⁺ T cells percentage and INF-γ down-regulated. In conclusion, CsESP and HBeAg co-incubation more distinctly suppressed maturation of BMDCs resulting in increase of IL-10 and decrease of IL-12 highly possible by up-regulation of MR and down-regulation of TLR-4 of BMDCs, and successively induce Th2 immune skewing. These findings laid the cornerstone to further clarify immune responses during the co-infection contributing to the better precise treatment and progression assessment of co-infection patients.