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

Abstract

Abstract Background Co-infection with Clonorchis sinensis (C. sinensis) and Hepatitis B virus (HBV) are commonly observed in endemic areas of Clonorchiasis. Our previous analysis demonstrated that C. sinensis and HBV coinfection could affect Th1/Th2 cytokines production and C. sinensis infection might aggravate the disease state of HBV infection. The immune mechanisms related to the pathogenesis of co-infection are worthy of investigation. Methods Myeloid-derived suppressor cells (MDSCs) are associated with chronic inflammation. Dendritic cells (DCs) are the key link between innate and adaptive immunity. The excretory-secretory products from C. sinensis (CsESP) play key roles in interaction between the worm and the host. Hepatitis B e antigen (HBeAg) is thought to contribute to viral persistence by decreasing the innate and adaptive immune response. So that the response of immune cells to CsESP and HBeAg co-stimulation in vitro were explored in the current study. Bone marrow (BM) cells were stimulated by GM-CSF and IL-4 and then co-incubation with CsESP and HBeAg in vitro. MDSCs accumulation, surface costimulatory molecules and cytokines release of BM derived DCs (BMDCs), and the consequent effectors on Th1/Th2 polarization to the co-stimulated BMDCs were analyzed by flow cytometry and ELISA. In addition, pattern recognition receptors on the surface of BMDCs in co-stimulation were detected by real-time PCR. Results 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. Conclusions CsESP and HBeAg co-incubation more distinctly promoted MDSCs, suppressed maturation of BMDCs highly possible by up-regulation of MR and down-regulation of TLR-4 of BMDCs, and successively induce Th2 immune skewing. Our work 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.