CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2022, Vol. 40 ›› Issue (6): 708-716.doi: 10.12140/j.issn.1000-7423.2022.06.003

• ORIGINAL ARTICLES • Previous Articles     Next Articles

Changes of ST2+ T cell subset function and their immune checkpoint molecule expression in the peritoneal cavity of mice infected with Echinococcus multilocularis

HOU Xin-ling1,2(), LI De-wei1,2, SHI Yang1,2, WANG Mao-lin1,2, ZIBIGU Rousu1,2, ABIDAN Ainiwaer1,2, ZHENG Xu-ran1,2, KANG Xue-jiao1,2, WANG Hui1,2, LI Jing1,2, ZHANG Chuan-shan1,2()   

  1. 1. Basic Medical College, Xinjiang Medical University, Urumqi 852204, China
    2. Clinical Medicine Institute, State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Xinjiang Key Laboratory of Echinococcosis, the First Affiliated Hospital of Xinjiang Medical University, Urumqi 852204, China
  • Received:2022-03-28 Revised:2022-09-16 Online:2022-12-30 Published:2022-12-26
  • Contact: ZHANG Chuan-shan E-mail:465778824@qq.com;dashan0518@126.com
  • Supported by:
    National Key Research and Development Program of China(2021YFC2300800);National Key Research and Development Program of China(2021YFC2300801);National Natural Science Foundation of China(82160396);National Natural Science Foundation of China(81760368);Key Laboratory Opening Project of Xinjiang Uygur Autonomous Region(2020D04007)

Abstract:

Objective To investigate the effect of Echinococcus multilocularis infection on the function of ST2+ T cell subsets and the expression of immune checkpoint molecules in the abdominal cavity of mice. Methods Eleven BALB/c mice were randomly divided into the infection group (5) and control group (6). Each mouse in the infection group was inoculated with 4 000 E. multilocularis protoscoleces via the hepatic portal vein, and the control group was injected with the same amount of normal saline. After 24 weeks of infection, RPMI 1640 was injected intraperitoneally into the mice to collect the intraperitoneal fluid, which was centrifuged to harvest lymphocytes. Flow cytometry was used to screen different T cell subsets in mouse abdominal cavity, detect the expression change of growth stimulating gene 2 protein (ST2), compare different ST2+ T cell subsets’ functions and the proportion and the absolute number of cells which express molecular killer cell agglutinin like receptor G1 (KLRG1), lymphocyte activating gene 3 (LAG3) and programmed death receptor 1 (PD-1), and the cells which secrete cytokines interferon-γ (IFN-γ), interleukin-4 (IL-4) and IL-17A. SPSS 25.0 software was used for statistical analysis, and independent sample t-test was used. Results At 24 weeks after infection, cystic or solid lesions were found in the abdominal cavity of mice in the infection group, and the absolute number of ST2+CD4+ T cells was (5.06 ± 3.06) × 104, the absolute number of memory ST2+CD4+ T cells is (4.66 ± 3.18) × 104, higher than that of the control group (3.31 ± 2.77) × 103 and (3.27 ± 2.77) × 103 (t = 3.442, 3.035; P < 0.05). The percentage of ST2+CD4+ T cells in the abdominal cavity of the infected mice was (22.78 ± 6.05)%, and the absolute number was (4.66 ± 3.18) × 104, both higher than the proportion and the absolute number of non-memory ST2+CD4+ T cells[(6.68 ± 1.25)% and (3.88 ± 5.20) × 103 ] (t = 5.830, 2.962; P < 0.01, 0.05). The percentage of ST2+CD8+ T cells in the abdominal cavity of infected mice was (7.03 ± 1.09)%, higher than that of non-memory ST2+CD8+ T cells (4.10 ± 1.57)% (t = 3.417, P < 0.01). The absolute number of memory ST2+CD4+ T cells expressing KLRG1, LAG3 and PD-1 in the infection group was (2.77 ± 1.41) × 103, (5.52 ± 3.95) × 103, (6.59 ± 3.75) × 103, higher than that of the control group (3.66 ± 6.42) × 102, (1.67 ± 0.72) × 102, (1.69 ± 1.49) × 103 (t = 3.760, 3.356, 2.956; P < 0.01, 0.05, 0.05). IFN-γ is secreted by ST2+CD4+ T and ST2+CD8+ T cells in the abdominal cavity of mice in the infection group. The proportion was (5.48 ± 1.33)% and (16.24 ± 4.08)%, lower than (14.82 ± 3.04)% and (44.70 ± 5.31)% in the control group (t = -6.325, -9.786; P < 0.01). The proportion of memory ST2+CD8+ T cells secreting IL-4 in infected mice was (13.10 ± 3.60)%, higher than that in control mice (4.59 ± 0.36)% (t = 5.264, P < 0.01). Conclusion The expression of ST2 on the surface of peritoneal T cells and memory T cells was up-regulated in E. multilocularis-infected mice, and the percentage of KLRG1, LAG3 and PD-1 molecules were upregulated on memory ST2+ T cells with a concomitant decrease in IFN-γ secretion capacity, suggesting the memory ST2+ T cells showing immune function exhaustion.

Key words: Echinococcus multilocularis, BALB/c mice peritoneal cells, Growth stimulation expressed gene 2, T cells, Immune checkpoint

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