A 21.6 kDa tegumental protein of Clonorchis sinensis induces a Th1/Th2 mixed immune response in mice

Abstract

Introduction Clonorchis sinensis is a major parasite affecting the Korea population. Despite the high infection rate and pathogenicity, very few studies have been conducted to investigate the immune responses against the proteins of C. sinensis.MethodsIn this study, in vitro immune response induced by a recombinant 21.6 kDa tegumental protein derived from C. sinensis (rCsTegu21.6) was confirmed in murine dendritic cells and T cells. For the in vivo analysis, each mouse was immunized three times. Total serum IgG and T cell cytokine production were determined by ELISA, while T cell proliferation was detected by a WST (Water‐Soluble Tetrazolium salt)‐1 assay.ResultsIn vitro tests indicated that rCsTegu21.6 treatment increased the expression of surface molecules, such as CD40 (77%), CD80 (52%) and CD86 (46%), on murine dendritic cells and the secretion of cytokines (TNF‐α, IL‐6, IL‐1β, IL‐10, and IL‐12p70). Moreover, co‐culturing dendritic cells activated by rCsTegu21.6 with allogenic T cells induced T cell proliferation over time. rCsTegu21.6 also stimulated specific antibody production and cytokine secretion [IL‐2, IL‐4, and interferon (IFN)‐γ)] from T cells following immunization in vivo. Notably, rCsTegu21.6 predominantly induced IgG1 production and secretion of the Th2 cytokine IL‐4, regardless of the type of adjuvant used.ConclusionThese results serve as a foundation for the development of tegumental protein‐based vaccines against C. sinensis.

Molecular Mechanisms of Clonorchis sinensis-Host Interactions and Implications for Vaccine Development

“…This complexity results from the fact that the parasite produces different types of compounds involved in its pathogenicity. Generally, during the life cycle of its definitive host, there are massive compounds of the parasite included excretory-secretory products (ESPs), tegumental proteins ( Chung et al, 2018 ), cyst wall-derived proteins ( Wang et al, 2012 ), egg-derived proteins ( Chen et al, 2017 ), and metabolism-related enzymes among others ( Shi et al, 2020 ). Furthermore, it seems that some compounds excreted by the parasite appear to depend on its stages of development, which implies that the juvenile in the early stages of infection may secrete specific compounds that are different from those excreted in the other stages of infection ( Table 1 ; Figure 2 ) ( Wang et al, 2012 ; Bian et al, 2014 ; Mao et al, 2015 ; Xu et al, 2015 ; Chen et al, 2017 ).…”

“…Furthermore, it seems that some compounds excreted by the parasite appear to depend on its stages of development, which implies that the juvenile in the early stages of infection may secrete specific compounds that are different from those excreted in the other stages of infection ( Table 1 ; Figure 2 ) ( Wang et al, 2012 ; Bian et al, 2014 ; Mao et al, 2015 ; Xu et al, 2015 ; Chen et al, 2017 ). Although the compounds of C. sinensis proteins are complex, the available data showed that recombinant proteins derived from ESPs, tegumental proteins, egg-derived proteins, or proteins extracted directly from ESPs generally and preferentially target a specific immune cell type including innate immune cells such as macrophages, dendritic cells, and/or adaptive immune cells such as T lymphocytes ( Table 1 ) ( Habich et al, 2005 ; Xu et al, 2015 ; Kim et al, 2017b ; Chung et al, 2018 ; Zhao et al, 2018 ).…”

“…Several pieces of evidence have demonstrated that proteins produced by external organs such as the tegumental proteins, the cell wall proteins trigger the mixed type 1/type 2 immune response. Work carried out on tegumental protein derived from C. sinensis (rCsTegu21.6) ( Chung et al, 2018 ), C. sinensis tegumental protein 22.3 kDa (CsTP 22.3) ( Lee et al, 2017 ), C. sinensis paramyosin (CsPmy) ( Wang et al, 2012 ) from the cyst wall have all shown the involvement of these proteins in triggering the type 1/type 2 immune response in the host. Taking all these parameters into consideration, we speculate that proteins and compounds excreted rapidly by the larval stages and juvenile forms of the parasite possibly contribute to the triggering of type 1 immune reaction, while compounds excreted by adult parasites preferentially trigger type 2 immune reaction ( Figure 2 ; Table 1 ).…”

“…The use of recombinant proteins for vaccine development should take into account the ability of the target protein to activate both innate and adaptive immunity. A study has shown that the recombinant 21.6 kDa tegumental protein derived from C. sinensis was able to activate both innate and adaptive immune cells ( Chung et al, 2018 ). Mice immunized with rCsTegu21.6 showed an acceleration of expression of co-stimulatory molecules (CD40, CD80, and CD86) on dendritic cells, and an increase in pro-and anti-inflammatory cytokine production ( Chung et al, 2018 ).…”

Novel mechanism of hepatobiliary system damage and immunoglobulin G4 elevation caused by Clonorchis sinensis infection

“…, activating phagocytes, NK cells, and others to directly kill Clonorchis sinensis . Chung et al [ 70 ] confirmed that the Clonorchis sinensis coat protein rCsTegu21.6 stimulated T cell-specific antibody production and cytokine production of IL-2, IL-4, and IFN-γ in murine dendritic cells and T cell secretion. Th2 mainly produce IL-4, IL-5, IL-6, IL-10, IL-13, and other cytokines to promote the maturation of B cells, produce antibodies, and regulate humoral immunity.…”