CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES >
IL-18 enhances the immunoprotective effect of pcDNA3.1/SjOST48 against Schistosoma japonicum infection
Received date: 2019-12-26
Online published: 2020-07-07
Supported by
Scientific Research Project of Education Department of Hunan Province(15C1257);Outstanding Youth Project of Education Department of Hunan Province(17B240)
Objective To investigate if IL-18 can enhance the immunoprotective effect of pcDNA3.1/SjOST48 against Schistosoma japonicum infection. Methods pcDNA3.1/SjOST48 and pcDNA3.1/IL-18 eukaryotic vectors were constructed to express recombinant proteins. Western blotting was performed to detect the expression of pcDNA3.1/SjOST48 and pcDNA3.1/IL-18 in HeLa cells, and ELISA was performed to examine IL-18 levels in culture medium. One hundred BALB/c female mice were randomly divided into 5 groups: PBS group (blank control), pcDNA3.1 group (empty vector), pcDNA3.1/IL-18 group, pcDNA3.1/SjOST48 group, and pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group, and were immunized with corresponding recombinant plasmid (30 μg) for three times at intervals of 14 days by intramuscular injection (100 μg/ml) at the quadriceps of the left hind leg femur. Two weeks after the last immunization, five mice in each group were selected for blood collection, and serum levels of IgG and its subclasses (IgG1 and IgG2a) were detected by ELISA. Three weeks after the last immunization, 5 mice of each group were selected for collection of spleen, to isolate spleen lymphocytes under sterile conditions; and the contents of TNF-α, INF-γ, IL-4, IL-6 and IL-8 in the lymphocytes culture supernatant and the proliferation of spleen lymphocytes were assessed by ELISA. Two weeks after the last immunization, 15 mice of each group were infected with 20 ± 1 cercariae of Schistosoma japonicum and sacrificed 6 weeks later. The liver tissue was obtained aseptically to calculate egg reduction rate; adult worms were collected by portal vein perfusion to calculate worm reduction rate. Another portion of liver tissue was used for hematoxylin & eosin (HE) staining to observe the amount of S. japonicum egg granuloma and inflammatory infiltration. Results ELISA results showed that at two weeks after the last immunization, the IgG antibody levels in mice of the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group, the pcDNA3.1/SjOST48 group, and the pcDNA3.1/IL-18 group were 0.82 ± 0.07, 0.41 ± 0.06, and 0.16 ± 0.05, respectively, all significantly higher than that in the pcDNA3.1 group (0.12 ± 0.03, P < 0.05). The IgG antibody level of the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group was significantly higher than those of the pcDNA3.1/SjOST48 group and the pcDNA3.1/IL-18 group (P < 0.05). The IgG2a/IgG1 ratio in the pcDNA3.1/SjOST48+pcDNA3.1/SjOST48 and pcDNA3.1/SjOST48 groups were 4.02 ± 0.01 and 2.51 ± 0.01 (P < 0.05), respectively, both >1, while those of the other 3 groups were all <1. At 3 weeks after the last immunization, the contents of IL-2, TNF-α, INF-γ, IL-6 and IL-17 in the supernatant of spleen lymphocytes in the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group were (101.82 ± 8.90) pg/ml, (738.02 ± 146.22) pg/ml, (593.41 ± 51.07) pg/ml, (685.64 ± 171.2) pg/ml and (261.32 ± 48.19) pg/ml, respectively, all significantly higher than those in the pcDNA3.1/SjOST48 group [(55.82 ± 9.69) pg/ml, (538.21 ± 85.26) pg/ml, (393.41 ± 51.07) pg/ml, (335.64 ± 62.63) pg/ml, (118.32 ± 8.91) pg/ml] (P < 0.05) and the pcDNA3.1/IL-18 group [(35.16 ± 6.43) pg/ml, (284.40 ± 69.96) pg/ml, (141.91 ± 24.48) pg/ml, (198.44 ± 38.15) pg/ml, and (47.66 ± 14.33) pg/ml] (P < 0.05). All the three groups had significantly higher contents of IL-2, TNF-α, INF-γ, IL-6 and IL-17 than the pcDNA3.1 group [(12.91 ± 8.01) pg/ml, (74.86 ± 6.64) pg/ml (23.75 ± 6.06) pg/ml, (82.75 ± 10.96) pg/ml, and (22.91 ± 13.80) pg/ml, respectively] (P < 0.05). The content of IL-4 in the supernatant of spleen lymphocytes in the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group was (12.28 ± 7.08) pg/ml, which showed no significant difference from those of the pcDNA3.1/SjOST48 [(15.03 ± 10.12) pg/ml], pcDNA3.1/IL-18 [(13.59 ± 4.42) pg/ml] and pcDNA3.1 groups [(16.13 ± 10.08) pg/ml] (P > 0.05). The proliferation level of spleen lymphocytes in the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group was 11.84 ± 0.16, higher than that in the pcDNA3.1/SjOST48 group (5.93 ± 0.25) (P < 0.05) and the pcDNA3.1/IL-18 group (3.19 ± 0.36) (P < 0.05), and all three were higher than that in the pcDNA3.1 group (2.08 ± 0.16) (P < 0.05). Six weeks after S. japonicum infection, the average number of adult worms detected from mice in the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group was (14.33 ± 1.08), and the worm reduction rate and egg reduction rate were 46.19% and 44.68%, respectively, significantly higher than those of the pcDNA3.1/SjOST48 immunized group (32.18% and 35.78%) and the pcDNA3.1 /IL-18 group (13.22% and 16.68%) (P < 0.05). HE staining of liver tissue showed that, in comparison to other groups, mice in the pcDNA3.1/SjOST48+pcDNA3.1/IL-18 group had fewer nodules of worm eggs on the liver surface and significantly decreased S. japonicum egg granulomas, and the inflammatory infiltration was unapparent. Conclusion IL-18 can induce a higher level of Th1 and Th17 immune response in mice immunized with pcDNA3.1/SjOST48, and enhance the immuno-protective effects of pcDNA3.1/SjOST48 against S. japonicum infection.
Key words： Schistosoma japonicum; IL-18; pcDNA3.1/SjOST48; Candicate antigen; Immune protection
Xiao TAN , Chu-li XIAO , Fei XIAO , Shuo WANG , Rui QING , Ze-zhi HUANG . IL-18 enhances the immunoprotective effect of pcDNA3.1/SjOST48 against Schistosoma japonicum infection[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2020 , 38(3) : 279 -285 . DOI: 10.12140/j.issn.1000-7423.2020.03.004
| [1] | McManus DP, Dunne DW, Sacko M, et al. Schistosomiasis[J]. Nat Rev Dis Primers, 2018,4:13. |
| [2] | Lei ZL, Zhou XN. Progress and challenges of the national schistosomiasis control program during the period of the 12th five-year plan[J]. Chin J Parasitol Parasit Dis, 2014,32(2):81-85. (in Chinese) |
| [2] | ( 雷正龙, 周晓农. 血吸虫病“十二五”防治规划实施进展及面临的挑战[J]. 中国寄生虫学与寄生虫病杂志, 2014,32(2):81-85.) |
| [3] | Tebeje BM, Harvie M, You H, et al. Schistosomiasis vaccines: where do we stand?[J]. Parasit Vectors, 2016,9:528. |
| [4] | Shen S, Luo JT, Ye JP. Mitochondrial function regulated by Beclin1 in liver fibrosis in schistosomiasis[J]. Chin J Parasitol Parasit Dis, 2020,38(1):41-46. (in Chinese) |
| [4] | ( 沈双, 罗军涛, 叶建平. 血吸虫病肝纤维化过程中Beclin1调节线粒体功能的初步研究[J]. 中国寄生虫学与寄生虫病杂志, 2020,38(1):41-46.) |
| [5] | Liu YT, Hong Y, Zhang M, et al. Cloning, expression of gene SjOST48 from Schistosoma japonicum and evaluation of the immunoprotective efficacy of r SjOST48 in mice[J]. Chin J Biotechnol, 2015,31(4):501-511. (in Chinese) |
| [5] | ( 刘艳涛, 洪炀, 张旻, 等. 日本血吸虫SjOST48基因的克隆、表达及其重组蛋白免疫保护效果分析[J]. 生物工程学报, 2015,31(4):501-511.) |
| [6] | Ge YX, Zhang JF, Pan YM, et al. Preliminary study to create an animal model of cerebral granuloma by injecting Schistosoma japonicum eggs through the carotid artery[J]. J Pathog Biol, 2017,12(9):864-867, 878. (in Chinese) |
| [6] | ( 葛宇曦, 张键锋, 潘永明, 等. 颈动脉注射血吸虫虫卵建立兔脑肉芽肿模型的研究[J]. 中国病原生物学杂志, 2017,12(9):864-867, 878.) |
| [7] | Mekonnen ZA, Grubor-Bauk B, Masavuli MG, et al. Toward DNA-based T-cell mediated vaccines to target HIV-1 and hepatitis C virus: approaches to elicit localized immunity for protection[J]. Front Cell Infect Microbiol, 2019,9:91. |
| [8] | Wei F, Liu Q, Gao SY, et al. Enhancement by IL-18 of the protective effect of a Schistosoma japonicum 26kDa GST plasmid DNA vaccine in mice[J]. Vaccine, 2008,26(33):4145-4149. |
| [9] | Cheng HB, Zhou YF, Zhang SJ, et al. Effects of SjRPS4oCB and IL-18 on the granuloma formation caused by eggs of Schistosoma japonicum in mice[J]. J Pathog Biol, 2018,13(8):855-858. (in Chinese) |
| [9] | ( 程红兵, 周云飞, 张树菊, 等. IL-18联合SjRPS4oCB多价疫苗免疫对血吸虫病小鼠肝脏虫卵肉芽肿形成的影响[J]. 中国病原生物学杂志, 2018,13(8):855-858.) |
| [10] | López-Yglesias AH, Camanzo E, Martin AT, et al. TLR11-independent inflammasome activation is critical for CD4+ T cell-derived IFN-γ production and host resistance to Toxoplasma gondii [J]. PLoS Pathog, 2019,15(6):e1007872. |
| [11] | Gao X, Xu K, Yang G, et al. Construction of a novel DNA vaccine candidate targeting F gene of genotype Ⅶ Newcastle disease virus and chicken IL-18 delivered by Salmonella[J]. J Appl Microbiol, 2019,126(5):1362-1372. |
| [12] | Sun L, Hu Y, Shen YJ, et al. γδ T cells-secreted IL-17A aggravates liver fibrosis in mice infected with Schistosoma japonicum activating hepatic stellate cells[J/OL]. Chin J Parasitol Parasit Dis, 2020, 38: (2020-04-13)[2019-12-10]. https://kns.cnki.net/KCMS/detail/31.1248.R.20200410.1429.004.html. (in Chinese) |
| [12] | ( 孙磊, 胡媛, 沈玉娟, 等. γδT细胞分泌IL-17A激活肝星状细胞促进日本血吸虫感染小鼠肝纤维化[J/OL]. 中国寄生虫与寄生虫病杂志, 2020, 38: (2020-04-13)[2019-12-10]. https://kns.cnki.net/KCMS/detail/31.1248.R.20200410.1429.004.html.) |
| [13] | Da’Dara AA, Li CL, Yu XL, et al. Prime-boost vaccine regimen for SjTPI and SjC23 schistosome vaccines, increases efficacy in water buffalo in a field trial in China[J]. Front Immunol, 2019,10:284. |
| [14] | Ganley-Leal LM, Guarner J, Todd CW, et al. Comparison of Schistosoma mansoni irradiated cercariae and Sm23 DNA vaccines[J]. Parasite Immunol, 2005,27(9):341-349. |
| [15] | Arnon R, Tarrab-Hazdai R, Steward M. A mimotope peptide-based vaccine against Schistosoma mansoni: synjournal and characterization[J]. Immunology, 2000,101(4):555-562. |
| [16] | Gurunathan S, Klinman DM, Seder RA. DNA vaccines: immunology, application, and optimization[J]. Annu Rev Immunol, 2000,18(1):927-974. |
| [17] | Sparwasser T, Miethke T, Lipford G, et al. Bacterial DNA causes septic shock[J]. Nature, 1997,386(6623):336-337. |
| [18] | Farwa A, He C, Xia LF, Zhou H. Immune modulation of Th1, Th2, and T-reg transcriptional factors differing from cytokine levels in Schistosoma japonicum infection[J]. Parasitol Res, 2018,117(1):115-126. |
/
| 〈 |
|
〉 |