Institute of Parasitology of the Slovak Academy of Sciences, Hlinkova 3, 040 01, Košice, Slovakia.
The University of Veterinary Medicine and Pharmacy in Košice, Komenského 68/73, 040 01, Košice, Slovakia.
Parasit Vectors. 2021 Jan 18;14(1):54. doi: 10.1186/s13071-020-04541-0.
Here, Mesocestoides (M.) vogae infection in mice is proposed as a suitable experimental model for studying the immunity in the peritoneal cavity of mice.
To investigate the kinetics of immune parameters in M. vogae-infected mice, we detected, using flow cytometry, the expression of selected lymphoid and myeloid markers within the peritoneal cell population at day 0, 3, 6, 10, 14, 19, 25, 30 and 35 post-infection. Then, using ELISA, we analyzed the cytokine IFN-γ, TGF-β, IL-4 and IL-10 responses and the levels of anti-M. vogae IgG and IgM antibodies in the peritoneal lavage fluid. Cells isolated from the peritoneal cavity were subjected to further molecular analysis. To assess cell activation, peritoneal cells were exposed to LPS, and culture supernatants were collected and assayed for the level of cytokines and production of nitrite. Ly6C+ and Ly6G+ cells were isolated using MACS from the peritoneal cells at day 35 post-infection. Both MACS-isolated subsets were co-cultured with preactivated T cells to measure their suppressive capacity. Next, the role of parasite excretory-secretory antigens in induction of CD11b+ myeloid cells with the suppressive phenotype and the production of IL-10 was examined.
In the peritoneal cavity an initial increase of CD11b+Gr-1+F4/80MHC II cells, NK, NKT cells and CD8+ cytotoxic T cells was observed in the first week of infection. At day 14 post-infection, an increase in the number of myeloid CD11b+Gr-1+ cells was detected, and most of this cell population expressed low levels of F4/80 and MHC II in later stages of infection, suggesting the impairment of antigen-presenting cell functions, probably through the excretory-secretory molecules. Moreover, we confirmed that peritoneal Gr1+ cells (Ly6C+ and Ly6G+ population) are phenotypically and functionally consistent with myeloid-derived suppressor cells. Metacestode infection elicited high levels of IL-10 and upregulated STAT-3 in peritoneal cells. A higher level of IgM suggests that this isotype may be predominant and is involved in the host protection.
Mesocestoides vogae tetrathyridia induced the recruitment of immunosuppressive cell subsets, which may play a key role in the downregulation of immune response in long-term parasitic diseases, and excretory-secretory antigens seem to be the main regulatory factor.
本研究提出，细粒棘球蚴（M. vogae）感染小鼠可作为研究腹腔免疫的合适实验模型。
为了研究 M. vogae 感染小鼠的免疫动力学，我们使用流式细胞术在感染后第 0、3、6、10、14、19、25、30 和 35 天检测腹腔细胞群中选定的淋巴和髓样标记物的表达。然后，我们使用 ELISA 分析细胞因子 IFN-γ、TGF-β、IL-4 和 IL-10 反应以及腹腔灌洗液中抗 M. vogae IgG 和 IgM 抗体的水平。从腹腔中分离的细胞进行进一步的分子分析。为了评估细胞激活，将腹腔细胞暴露于 LPS 中，并收集培养上清液，检测细胞因子水平和亚硝酸盐的产生。在感染后第 35 天，使用 MACS 从腹腔细胞中分离出 Ly6C+和 Ly6G+细胞。将这两种 MACS 分离的亚群与预先激活的 T 细胞共培养，以测量其抑制能力。接下来，研究寄生虫排泄分泌抗原在诱导具有抑制表型的 CD11b+髓样细胞和产生 IL-10 中的作用。
在腹腔中，感染后第一周观察到 CD11b+Gr-1+F4/80MHC II 细胞、NK、NKT 细胞和 CD8+细胞毒性 T 细胞的初始增加。在感染后第 14 天，检测到髓样细胞 CD11b+Gr-1+细胞数量增加，在感染后期，该细胞群的大多数细胞表达低水平的 F4/80 和 MHC II，提示抗原呈递细胞功能受损，可能是通过排泄分泌分子。此外，我们证实腹腔 Gr1+细胞（Ly6C+和 Ly6G+群体）在表型和功能上与髓源性抑制细胞一致。囊尾蚴感染引起高水平的 IL-10 和 STAT-3 在腹腔细胞中上调。较高水平的 IgM 表明这种同型可能占主导地位，并参与宿主保护。
细粒棘球蚴四期幼虫诱导免疫抑制细胞亚群的募集，这可能在长期寄生虫病中下调免疫反应中发挥关键作用，排泄分泌抗原似乎是主要的调节因子。
