Soluble egg antigen of Schistosoma japonicum induces macrophage apoptosis in mice / 中国血吸虫病防治杂志

OBJECTIVE@#To investigate the dynamic changes of macrophage numbers and apoptosis during Schistosoma japonicum infection, and to investigate the possible mechanisms of macrophage apoptosis induced by S. japonicum soluble egg antigen (SEA).@*METHODS@#C57BL/6 mice at ages of 6~8 weeks were randomly divided into 4 groups, including three experimental groups and a normal control group. Each mouse in the experimental groups was infected with (12 ± 1) cercariae of S. japonicum via the abdominal skin, and all mice in an experimental group were sacrificed 3, 5, 8 weeks post-infection, respectively, while mice in the control group were not infected with S. japonicum cercariae and sacrificed on the day of S. japonicum infection in the experimental group. Mouse liver specimens and peritoneal exudation cells were sampled in each group, and the dynamic changes of macrophage numbers and apoptosis were detected. Mouse peritoneal macrophages were isolated, purified and treated with S. japonicum SEA, PBS and ovalbumin (OVA) in vitro, and the macrophage apoptosis was detected using flow cytometry. The mRNA and protein expression of BCL-2 protein family members were determined in macrophages using real-time quantitative PCR (qP-CR) and Western blotting assays, and the activation of caspase 3 was determined using flow cytometry and Western blotting. In addition, macrophages were in vitro treated with S. japonicum SEA in presence of a caspase inhibitor, H2O2 or N-acetyl-L-cysteine, and the apoptosis of macrophages was detected using flow cytometry.@*RESULTS@#The total macrophage numbers continued to increase in mouse liver [(0.873 ± 0.106) × 106, (2.737 ± 0.460) × 106 and (3.107 ± 0.367) × 106 cells, respectively; F = 81.900, P < 0.01] and peritoneal specimens [(5.282 ± 1.136) × 105, (7.500 ± 1.200) × 105 and (12.800 ± 0.800) × 105 cells, respectively; F = 55.720, P < 0.01] 3, 5 and 8 weeks post-infection with S. japonicum, and the numbers of apoptotic macrophages also continued to increase in mouse liver [(0.092 ± 0.018) × 106, (0.186 ± 0.025) × 106 and (0.173 ± 0.0270) × 106 cells; F = 57.780, P < 0.01] and peritoneal specimens [(0.335 ± 0.022) × 105, (0.771 ± 0.099) × 105 and (1.094 ± 0.051) × 105 cells; F = 49.460, P < 0.01] 3, 5 and 8 weeks post-infection with S. japonicum. The apoptotic rate of SEA-treated macrophages [(24.330 ± 0.784)%] was significantly higher than that of PBS-[(18.500 ± 1.077)%] and OVA-treated macrophages [(18.900 ± 1.350)%] (both P values < 0.01). There were no significant differences in the mRNA or protein expression of Bcl-2 [Bcl - 2 mRNA expression: (1.662 ± 0.943) vs. (1.000 ± 0.000), t = 1.215, P > 0.05; BCL protein expression: (0.068 ± 0.004) vs. (0.070 ± 0.005), t = 0.699, P > 0.05], Bax [Bax mRNA expression: (0.711 ± 0.200) vs. (1.000 ± 0.000), t = 2.507, P > 0.05; BAX protein expression: (0.089 ± 0.005) vs. (0.097 ± 0.003), t = 2.232, P > 0.05] and Bak [Bak mRNA expression: (1.255 ± 0.049) vs. (1.00 ± 0.00), t = 0.897, P > 0.05; BAK protein expression: (0.439 ± 0.048) vs. (0.571 ± 0.091), t = 2.231, P > 0.05] between in SEA- and PBS-treated macrophages. S. japonicum SEA induced macrophage apoptosis in the presence of a caspase inhibitor (F = 0.411, P > 0.05); however, SEA failed to induce macrophage apoptosis in the presence of H2O2 or NAC (F = 11.880 and 9.897, both P values < 0.05).@*CONCLUSIONS@#S. japonicum SEA may induce macrophage apoptosis through promoting reactive oxygen species expression during S. japonicum infections in mice.

Changes of liver fibrosis-related miRNAs induced by soluble egg antigen of Schistosoma japonicum / 中国血吸虫病防治杂志

Objective To investigate the expression of miRNA associated with hepatic fibrosis induced by Schistosoma ja-ponicum soluble egg antigen stimulation in mouse hepatocytes(AML12),so as to lay the foundation for clarifying the mecha-nism of schistosome infection leading to hepatic fibrosis. Methods The expressions of miR-122,miR-182,miR-23b,miR-27b and KSRP in AML12 cells treated with SEA were measured by q-PCR. KSRP protein in cell lyses was measured by Western blotting. AML12 cells were transfected with miR-27b precursor or anti-miR-27b for 24 h,then q-PCR was adopted to determine KSRP mRNA,and KSRP protein was detected by Western blotting. Results The expressions of miR-182,miR-23b and miR-27b were decreased and miR-122 was increased in AML12 cells following SEA treatment(all P<0.05). An increase of mRNA and protein of KSRP expression was also observed in AML12 cells after SEA stimulation(both P<0.05). In addition,KSRP mRNA expression was not changed significantly in AML12 cells transfected with anti-miR-27b or miR-27b precursor,and miR-27b precursor reduced KSRP protein expression as compared with the control. In contrast,the expression of KSRP protein was increased in the anti-miR-27b group and decreased in the miR-27b precursor group. Conclusions After the stimulation of SEA,the expressions of a variety of liver fibrosis-related miRNAs and KSRP change in murine hepatocytes,including miR-27b. And miR-27b can regulate the expression of KSRP. These findings might lay a foundation for further study on the molecular mechanism of fibrosis induced by schistosome infection.

Establishment of A1E3 and B1C4 monoclonal antibody-based ELISA for de-tecting circulating antigen of Schistosoma japonicum and its preliminary ap-plication / 中国血吸虫病防治杂志

Objective To establish A1E3 and B1C4 monoclonal antibody-based ELISA for detecting circulating antigen of Schistosoma japonicum and explore its application value in the field. Methods The characteristics of A1E3 and B1C4 monoclonal antibodies were analyzed by SDS-PAGE and Western blotting. The SEA-based ELISA was used to evaluate the titers of A1E3 and B1C4. The orthogonal test was used to determine the best concentration of coating antibody B1C4 and optimal working concentra-tion of A1E3-HRP. Under the optimal conditions,the serum samples of 20 acute schistosomiasis cases,46 chronic schistosomiasis cases,and 20 control sera were tested to evaluate its detection sensitivity and specificity. Seventy-two antibody positive serum sam-ples from Jiangling County of Hubei Province were detected and compared to a commercially available ELISA kit,to evaluate the detection effects of this method. Results The results of SDS-PAGE demonstrated that the purified A1E3 and B1C4 contained a clear heavy chain with molecular weight of 88 000 and 52 000 respectively and had the same light chain with molecular weight of 20 000;while Western blotting demonstrated that A1E3 and B1C4 could be recognized by SEA and serum samples of acute schis-tosomiasis cases. The SEA-based ELISA demonstrated the titers of B1C4 and A1E3 were 1∶105 and 1∶30 000,respectively. The serum samples from all the acute cases and 86.9% of the chronic cases showed a positive reaction. All of the control sera from healthy persons gave a negative response. The positive rates of the double monoclonal antibody ELISA and commercial ELISA for detecting the circulating antigen were 45.8%and 43.1%respectively,and there was no significant difference between the results of the two methods. Conclusion A1E3 and B1C4 monoclonal antibody-based ELISA is established successfully. It exhibits a high sensitivity and specificity in detecting circulating antigen of Schistosoma japonicum.

T Regulatory Cell Responses to Immunization with a Soluble Egg Antigen in Schistosoma mansoni-Infected Mice

The aim of the study is to characterize the phenotypes of CD4+ CD25+ T regulatory cells within the liver granulomas and association with both Foxp-3 gene expression and splenic cytokines. Naive C57BL/6 mice were intravenously injected with multiple doses of the soluble egg antigen (SEA) 7 days before cercarial infection. The immunized and infected control groups were sacrificed 8 and 16 weeks post-infection (PI). Histopathology, parasitological parameters, splenic phenotypes for T regulatory cells, the FOXP-3 expression in hepatic granuloma using real-time PCR, and the associated splenic cytokines were studied. Histopathological examination of the liver revealed remarkable increase in degenerated ova within hepatic granuloma which decreased in diameter at weeks 8 and 16 PI (P<0.01). The percentage of T regulatory cells (CD4+ CD25+) increased significantly (P<0.01) in the immunized group compared to the infected control at weeks 8 and 16 PI. The FOXP-3 expression in hepatic granulomas increased from 10 at week 8 to 30 fold at week 16 PI in the infected control group. However, its expression in the immunized group showed an increase from 30 at week 8 to 70 fold at week 16 PI. The splenic cytokine levels of pro-inflammatory cytokines, IFN-gamma, IL-4, and TNF-alpha, showed significant decreases (P<0.05) compared to the infected control group. In conclusion, the magnitude and phenotype of the egg-induced effects on T helper responses were found to be controlled by a parallel response within the T regulatory population which provides protection in worm parasite-induced immunopathology.

Effect of soluble worm antigen and soluble egg antigen of Schistosoma japonicum on apoptosis and cell-cycle of CD4~+ T lymphocytes / 中国血吸虫病防治杂志

Objective To investigate and compare the different effects of soluble adult wornl antigen(SWA)and soluble egg antigen(SEA)of Schistosoma japonicum on the apoptosis and cell-cycle of routine CD4~+T cells.Methods Purified CD4~+T ceUs from normal C57BL/6 mice were cultured with CFSE labeled antigen presenting clls in the presence of different stimuli for 36 h.Flow cytometry(FCM)was used to detect the apoptosis of CD4~+T cells by fluorescence conjugated caspase-3 antibodie staining.The flow cytometry was used to analyze the cell-cycle of CD4~+T cells cultured as described above for 96 h by propidium iodide staining.Results Compared with the apoptosis percentage of CD4~+T cells[(1.24±0.29)%]in the SEA stimulated group,that in the SWA stimulated group[(1.52±0.38)%]did not show statistically significant difference(P>0.05).Compared with the cell percentages in G1 phase[(78.91±2.98)%],S phase[(7.39±0.85)%]and G2/M phase[(10.69±1.05)%] in the SWA stimulated group,that of the G1 phase[(59.42±1.32)%]was significantly lower,but those in the S phase[(21.07±O.88)%] and G2/M phase[(18.88±1.21)%]were significantly increased in the SEA stimulated group(P<0.01).Conclusions There is no statistically significant difference between the apoptosis levels of CD4~+T ceHs stimulated by SWA and SEA.However,SEA significantly promotes the progression of the cell-cycle of CD4~+T cells compared with SWA.

Analysis of early diagnostic fraction antigens of cercariae, adult worms and eggs of Schistosoma japonicum / 中国血吸虫病防治杂志

Objective To find out the valuable early diagnostic antigen of Schistosoma japonicum. Methods The sera of rabbits were collected at different time after the rabbits were infected with cercariae of Schitosoma japonicum. The fractions of the soluble cercaria antigen (SCA), soluble adult worm antigen (AWA) and soluble egg antigen (SEA) were separated by SDS-PAGE and recognized by Western blotting with rabbits' sera of different time of post-infection. Results In Western blotting, the bands of 94, 48, 41, 40 kDa and 38 kDa of SCA appeared the earliest and were recognized by the rabbits sera of 2-week post-infection, the bands of 71 kDa and 23 kDa of SCA reacted with the rabbits sera of 3-week post-infection strongly. The bands of 71 kDa and 58 kDa of AWA appeared the earliest and were recognized by rabbits sera of 3-week post-infection. The bands of SEA reacted earliestly to the rabbits sera of 4-week post-infection were 270, 151, 73, 69, 50 kDa and 24 kDa. Conclusion The fraction antigens of 94, 71, 48, 41, 40, 38 kDa and 23 kDa of SCA, the fraction antigens of 71 kDa and 58 kDa of AWA and the fraction antigens of 270, 151, 73, 69, 50 kDa and 24 kDa of SEA could be recognized by sera of acute infected rabbits and might have potential early immuno-diagnosis value for schistosomiasis.

Study on Diagnosis of Schistosomiasis by ELISA Using Periodate-treated Soluble Egg Antigen / 中国寄生虫学与寄生虫病杂志

0. 05) and the specificity is higher than that of the SEA-ELISA (P

Effect of astragalosides on schistosomal hepatic fibrosis in vitro / 中国药理学通报

Aim To observe the effect of astragalosides on proliferation and collagen synthesis of HSC-T6 cells driven using schistosoma japonicum soluble egg antigen-activated macrophage conditioned medium(SEA-MCM).Methods SEA-MCM was prepared by injection of Schistosoma japonicum SEA via mice peritoneal.The proliferation and collagen synthesis of HSC-T6 cells stimulated with SEA-MCM were measured using MTT colorimetric assay and()~3H-proline incorporation respectively.Results The proliferation and collagen production of HSC-T6 cells were significantly promoted by SEA-MCM.They were significantly suppressed after being treated with AST(32.5、65、130 mg?L~(-1)) showing concentration-dependent effect.Conclusion:Astragalosides may inhibit HSC-T6 cells proliferation and collagen production that was driven by SEA activated MCM in vitro.