NP30 stimulates Th17 differentiation through DC in Schistosomiasis Japonicum

Mesenchymal Stromal Cells-Derived Extracellular Vesicles Regulate Dendritic Cell Functions in Dry Eye Disease

We explored the therapeutic efficacy of Mesenchymal stromal cells-derived extracellular vesicles (MSC-EVs) and its inhibition of the functions of dendritic cells (DCs) in dry eye disease (DED). MSC-EVs were isolated from the culture supernatants of mesenchymal stromal cells (MSCs) and characterized. In vitro, human corneal epithelial cells (HCECs) were cultured in hyperosmotic medium to simulate the DED hyperosmotic environment and treated with MSC-EVs. Cell viability was assessed, and the expression of inflammatory cytokines was quantified. Next, we induced DED in female C57BL/6 mice and divided the mice into groups treated with either MSC-EVs or phosphate buffer solution (PBS) eye drops. Disease severity was assessed; mRNA expression of inflammatory cytokines was analyzed by RT-PCR; and Th17 cells were detected by flow cytometry. Lastly, we evaluated DCs by immunofluorescence and flow cytometric analysis to assess its amounts and maturation. MSC-EVs showed protective effects on HCECs under hyperosmotic stress in vitro, suppressing the expression of inflammatory cytokines. In vivo, mice topically treated with MSC-Evs presented reduced DED disease severity compared to PBS-treated mice. MSC-Evs downregulated the expression of inflammatory cytokines, including TNF-α, IL-6, and IL-1β, as well as the frequency of Th17 cells. Further investigation showed that MSC-EVs suppressed the increase of amounts and the maturation of DCs in DED. Changes of morphological characters of DCs were also inhibited by MSC-EVs. Our study revealed that MSC-EVs suppressed ocular surface inflammation by inhibiting DCs activation-mediated Th17 immune responses, explicating the therapeutic potential of MSC-EVs in DED and other ocular surface diseases.

Granulocytic myeloid-derived suppressor cells inhibit T follicular helper cells during experimental Schistosoma japonicum infection

Background

CD4⁺ T helper (Th) cells play critical roles in both host humoral and cellular immunity against parasitic infection and in the immunopathology of schistosomiasis. T follicular helper (Tfh) cells are a specialized subset of Th cells involved in immunity against infectious diseases. However, the role of Tfh cells in schistosome infection is not fully understood. In this study, the dynamics and roles of Tfh cell regulation were examined. We demonstrated that granulocytic myeloid-derived suppressor cells (G-MDSC) can suppress the proliferation of Tfh cells.

Methods

The levels of Tfh cells and two other Th cells (Th1, Th2) were quantitated at different Schistosoma japonicum infection times (0,3, 5, 8, 13 weeks) using flow cytometry. The proliferation of Tfh cells stimulated by soluble egg antigen (SEA) and soluble worm antigen (SWA) in vivo and in vitro were analyzed. Tfh cells were co-cultured with MDSC to detect the proliferation of Tfh cells labelled by 5(6)-carboxyfluorescein diacetate N-succinimidyl ester. We dynamically monitored the expression of programmed cell death protein 1 (PD-1) on the surface of Tfh cells and programmed cell death ligand 1 (PD-L1) on the surface of MDSC at different infection times (0, 3, 5, 8 weeks). Naïve CD4⁺ T cells (in Tfh cell differentiation) were co-cultured with G-MDSC or monocytic MDSC in the presence, or in the absence, of PD-L1 blocking antibody.

Results

The proportion of Tfh cells among CD4⁺ T cells increased gradually with time of S. japonicum infection, reaching a peak at 8 weeks, after which it decreased gradually. Both SEA and SWA caused an increase in Tfh cells in vitro and in vivo. It was found that MDSC can suppress the proliferation of Tfh cells. The expression of PD-1 on Tfh cells and PD-L1 from MDSC cells increased with prolongation of the infection cycle. G-MDSC might regulate Tfh cells through the PD-1/PD-L1 pathway.

Conclusions

The reported study not only reveals the dynamics of Tfh cell regulation during S. japonicum infection, but also provides evidence that G-MDSC may regulate Tfh cells by PD-1/PD-L1. This study provides strong evidence for the important role of Tfh cells in the immune response to S. japonicum infection.

Graphical abstract

IL-17A-producing γδ T cells promote liver pathology in acute murine schistosomiasis

Background

The main symptoms of schistosomiasis are granuloma and fibrosis, caused by Schistosoma eggs. Numerous types of cells and cytokines are involved in the progression of Schistosoma infection. As a class of innate immune cells, γδ T cells play critical roles in the early immune response. However, their role in modulating granuloma and fibrosis remains to be clarified.

Methods

Liver fibrosis in wild-type (WT) mice and T cell receptor (TCR) δ knockout (KO) mice infected with Schistosoma japonicum was examined via Masson’s trichrome staining of collagen deposition and quantitative reverse transcriptase-PCR (RT-PCR) of fibrosis-related genes. Granuloma was detected by hematoxylin-eosin (H&E) staining and quantified. Flow cytometry was used for immune cell profiling and for detecting cytokine secretion. The abundance of the related cytokines was measured using quantitative RT-PCR.

Results

The livers of S. japonicum-infected mice had significantly increased proportions of interleukin (IL)-17A producing γδ T cells and secreted IL-17A. Compared with the WT mice, TCR δ deficiency resulted in reduced pathological impairment and fibrosis in the liver and increased survival in infected mice. In addition, the profibrogenic effects of γδ T cells in infected mice were associated with enhanced CD11b⁺Gr-1⁺ cells, concurrent with increased expression of transforming growth factor (TGF)-β in the liver.

Conclusions

In this mouse model of Schistosoma infection, γδ T cells may promote liver fibrosis by recruiting CD11b⁺Gr-1⁺ cells. These findings shed new light on the pathogenesis of liver pathology in murine schistosomiasis.

NP30 stimulates Th17 differentiation through DC in Schistosomiasis Japonicum

The murine monoclonal anti‐idiotypic antibody, NP30, is a potential vaccine candidate against Schistosoma japonicum. Previous studies have revealed that NP30 has an immunoregulatory effect, but the underlying mechanism for this effect remains unknown. This study shows that NP30 induces dendritic cell (DC) maturation and increases the production of pro‐inflammatory cytokines. The expression of CD86 and MHC II was upregulated in DCs following stimulation with NP30 in vitro. Moreover, NP30 induced Th17 polarization by increasing the production of IL‐6 and TGF‐β. In vivo, Th17 differentiation was induced by the production of key pro‐inflammatory cytokines, including IL‐6and TGF‐β, from DCs of NP30‐immunized mice. These results indicate that NP30 promotes Th17 polarization through DC activation, preventing serious schistosomiasis.