Switched phenotypes of macrophages during the different stages of Schistosoma japonicum infection influenced the subsequent trends of immune responses.

BACKGROUND: Macrophages play crucial roles in immune responses during the course of schistosomal infections. METHODS: We currently investigated influence of immunocompetent changes in macrophages via microarray-based analysis, mRNA expression analysis, detection of serum cytokines, and subsequent evaluation of the immune phenotypes following the differentiation of infection-induced lymphocytes in a unique T1/T2 double-transgenic mouse model. RESULTS: The gradual upregulation of genes encoding YM1, YM2, and interleukin (IL)-4/IL-13 receptors in infected mice indicated the role of type 2 alternatively activated macrophages (M2, AAMφs) in immune responses after Schistosoma japonicum egg production. FACS analysis showed that surface markers MHC class II (IA/IE) and CD8α+ of the macrophages also exhibited a dramatic change at the various time points before and after egg-production. The transgenic mouse experiments further demonstrated that the shifting of macrophage phenotypes influenced the percentage of helper T (Th)-2 cells, which was observed to be higher than that of Th1 cells, which increased only at 3 and 5 weeks post-infection. The differentiation of effector B cells showed a similar but more significant trend toward type-2 immunity. CONCLUSION: These results suggest that the infection of mice with S. japonicum resulted in a final Th2- and Be2-skewed immune response. This may be due to phenotypic changes in the macrophages. The influence of alternatively activated macrophages was also activated by S. japonicum egg production. This study elucidated the existence of variations in immune mechanisms at the schistosome infection stages.

Immunopathological effects of Agaricus blazei Murill polysaccharides against Schistosoma mansoni infection by Th1 and NK1 cells differentiation.

In this study, we examined the ability of A. blazei Murill polysaccharides (AB-PS) to activate the immune system in vivo and the protective activity exhibited against parasitic S. mansoni in the murine model. AB-PS treatment significantly reduced the worm and egg burden in infected BALB/c and C57BL/6 mice with dose- and time-dependent manners. Additionally, a dose- and time-dependent expression of IL-2, INF-γ, and TNF-α cytokines was also observed in both strains of mice treatments. Using T1/T2 doubly transgenic mice, we demonstrated that AB-PS-treated mice splenocytes initiated early differentiation of Th1 and NK1 cells, which was consistent with the reduction course of Schistosoma infection. Although AB-PS treatment enhanced the Th1 response, it did not suppress Th2 cell activity in treated mice. Histopathological data of the livers showed AB-PS treatment significantly attenuated the liver fibrosis induced by S. mansoni eggs. AB-PS augmented type-1 responses by inducing Th1 and NK1 cell differentiation to effectively decrease the infection rate of S. mansoni. Furthermore, AB-PS treatment may not only inhibit the schistosome infection, but also improving the pathological effects of granulomas formation. This study provides evidence for a novel therapeutic potential, by which A. blazei Murill may be used to treat or prevent schistosome infection.

Combined IL-12 Plasmid and Recombinant SjGST Enhance the Protective and Anti-pathology Effect of SjGST DNA Vaccine Against Schistosoma japonicum.

Schistosomiasis is listed as one of most important tropical diseases and more than 200 million people are estimated to be infected. Development of a vaccine is thought to be the most effective way to control this disease. Recombinant 26-kDa glutathione S-transferase (rSjGST) has previously been reported to achieve a worm reduction rate of 42-44%. To improve the efficiency of the vaccine against Schistosoma japonicum, we immunized mice with a combination of pcDNA vector-encoded 26-kDa SjGST (pcDNA/SjGST), IL-12 expressing-plasmid (pIL-12), and rSjGST. Co-vaccination with pcDNA/SjGST, pIL-12, and rSjGST led to a reduction in worm burden, hepatic egg burden, and the size of liver tissue granulomas than that in the untreated infection controls. In addition, we detected high levels of specific IgG, IgG1, and IgG2a against the rSjGST antigen in infected mice vaccinated with this combination of pcDNA/SjGST, pIL-12, and rSjGST. Moreover, high expression levels of Th2 cytokines, including IL-4 and IL-10, were also detected in this group, without diminished levels of IL-12, INF-γ, and TNF-α cytokines that are related to parasite killing. In conclusion, we have developed a new vaccination regimen against S. japonicum infection and shown that co-immunization with pcDNA/SjGST vaccine, pIL-12, and rSjGST has significant anti-parasite, anti-hepatic egg and anti-pathology effects in mice. The efficacy of this vaccination method should be further validated in large animals such as water buffalo. This method may help to reduce the transmission of zoonotic schistosomiasis japonica.

Mitochondrial dynamics in the mouse liver infected by Schistosoma mansoni.

Mitochondrial dynamics is crucial for regulation of cell homeostasis. Schistosoma mansoni is one of the most common parasites known to cause liver disease. Mice infected by S. mansoni show acute symptoms of schistosomiasis after 8 weeks. Hence, in this study, we attempted to assess the direct effects of S. mansoni infection on mice liver, and to explore the expression of mitochondrial morphology, dynamics, and function. Our recent findings show that S. mansoni infection changes mitochondrial morphology and affects mitochondrial functions, which attenuates mitochondrial membrane potential and ATP generation. S. mansoni-infected mice increases mitochondrial numbers by upregulating of genes involved in mitochondrial biogenesis, including peroxisome proliferator-activated receptor c co-activator 1α (PGC1α) and mitochondrial transcription factor A (Tfam). This may promote mitochondria generation for accelerating the recovery of mitochondrial functions. Moreover, S. mansoni would disrupt mitochondrial dynamics including induced mitochondrial fission and promoted mitochondrial fragmentation in mice liver. More importantly, S. mansoni further stimulated upregulation both extrinsic and intrinsic apoptosis pathway in infected mice liver. The intrinsic pathway was triggered by cytochrome c release. Additionally, NFκB (nuclear factor-kappa B, p65) could play a protective role to inhibit apoptosis through reducing active caspase-3 expression. Therefore, our results confirmed the liver damage mechanism of experimental schistosomiasis in mice model.

A study of immunomodulatory genes responses to macrophages of Schistosoma japonicum infection during different stages by microarray analysis.

Macrophages initiate, modulate, and also serve as final effector cells in immune responses during the course of schistosomal infections. In this study, we investigated the gene expression profile and functional changes of macrophages in immune responses against the Schistosoma japonicum by microarray analysis. Hierarchical clustering analysis demonstrated that a significant switch in gene transformation associated with a type-1 response and linked with a type-2 cytokine phenotype occurs between 4.5 and 8 weeks post-infection. Moreover, the gene profiles at 3 later time-points following egg challenge were similar in complexity and magnitude. The data also showed that there were mostly inhibition of gene expression related TLR, IFN, MHC and TNFrsf at the switch between 4.5 and 8 weeks post-infection, It is suggested that these immunomodulatory genes may be down-regulated in defense against S. japonicum eggs and granuloma pathology. The induction of alternatively activated macrophage (AAMϕ) was important for dampening the inflammation in hepatic granulomas and contributing to a decrease in cytotoxicity. The gene expressions involved in repair/remodeling during liver fibrosis were also observed after egg production. Understanding the immune mechanisms associated with parasitic resistance, pathology of parasite infection, and parasite growth will provide useful insight on host-schistosome interactions and for the control of schistosomiasis.

Evaluation of recombinant fructose-1,6-bisphosphate aldolase ELISA test for the diagnosis of Schistosoma japonicum in water buffaloes.

Fructose-1,6-bisphosphate aldolase (FBPA) is an ubiquitous enzyme essential for glycolysis, gluconeogenesis and the Calvin cycle. It has been demonstrated to induce immune responses and to be useful in the immunodiagnosis of malaria. In this study, FBPA was cloned from the adult worms of Schistosoma japonicum and tested as an antigen for the diagnosis of S. japonicum infection in water buffaloes. Enzyme-linked immunosorbent assay (ELISA) was performed on the sera from 32 infected water buffaloes and 20 negative controls using the recombinant FBPA protein or soluble worm antigen preparation (SWAP) as an antigen. The OD cut-off values were determined to be 0.57 with 100% specificity and 100% sensitivity for the FBPA ELISA and 1.13 with 93.8% specificity and 95.0% sensitivity for the SWAP ELISA. These findings indicate that the recombinant FBPA of S. japonicum should be an useful diagnostic tool for the detection of antibodies against S. japonicum.

Polysaccharides from Antrodia camphorata mycelia extracts possess immunomodulatory activity and inhibits infection of Schistosoma mansoni.

Antrodia camphorata (AC) is a commonly used fungus in folk medicine for the treatment of viral hepatitis and cancer. AC polysaccharides (AC-PS) are reported to possess anti-inflammatory, anti-hepatitis B virus, and anticancer activities. In this study, we tested the in vivo effect of AC-PS on immune function by evaluating cytokine expression; on immunomodulation, by evaluating spleen cells; and on Schistosoma mansoni infection in mice. The induction of high levels of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) mRNA was detected in BALB/c mice after 2, 4, and 6 weeks of oral AC-PS administration. After 6 weeks of oral AC-PS administration to the BALB/c mice, the number of splenic dendritic cells, macrophages, and the surface expression of CD8 alpha+ and major histocompatibility class II I-A/I-E on dendritic cells increased. The CD4+/CD8+ ratio and number of B cells among splenocytes were also augmented. By using a disease model of parasitic infection, we found that AC-PS treatment inhibited S. mansoni infection in BALB/c mice. AC-PS appears to modulate the immune system of mice and has potential for preventing S. mansoni infection.

In vivo immunomodulatory effects of Antrodia camphorata polysaccharides in a T1/T2 doubly transgenic mouse model for inhibiting infection of Schistosoma mansoni.

Antrodia camphorata (A. camphorata) is a fungus commonly used for treatment of viral hepatitis and cancer in Chinese folk medicine. Extract of A. camphorate is reported to possess anti-inflammatory, antihepatitis B virus and anticancer activities. In this study, we tested the in vivo effects of polysaccharides derived from A. camphorata (AC-PS) on immune function by detection of cytokine expression and evaluation of the immune phenotype in a T1/T2 doubly transgenic mouse model. The protective effect of AC-PS in mice was tested by infection with Schistosoma mansoni. The induction of large amounts of IFN-gamma, IL-2 and TNF-alpha mRNA were detected after 2 and 4 weeks of oral AC-PS administration in BALB/c and C57BL/6 mice. In transgenic mice, 3 to 6 weeks of oral AC-PS administration increased the proportion of CD4(+) T cells and B cells within the spleen. More specifically, there was an increase of Th1 CD4(+) T cells and Be1 cells among spleen cells as observed by detection the of Type1/Type2 marker molecules. By using a disease model of parasitic infection, we found that AC-PS treatment inhibited infection with S. mansoni in BALB/C and C57BL/6 mice. AC-PS appears to influence the immune system of mice into developing Th1 responses and have potential for preventing infection with S. mansoni.

Application of recombinant Sjc26GST for serodiagnosis of Schistosoma japonicum infection in water buffalo (Bos buffelus).

Schistosomiasis japonica is currently the most serious parasitic disease in mainland China and it is estimated that several million people are infected. Furthermore, it is also responsible for the deaths of many domestic animals. In order to establish an effective diagnostic method, the gene encoding Sjc26GST was cloned and expressed in Escherichia coli as a fusion protein with His-tag. The purified reSjc26GST was used as an antigen for an enzyme-linked immunosorbent assay (ELISA) and for immunoblotting detection of Schistosoma japonicum antibodies in water buffaloes. Our results showed that mean OD values of specific serum IgG antibodies from egg-positive buffaloes were 3.37-fold higher than what was found in egg-negative buffaloes from non-endemic areas. The data also showed the OD value of the endemic egg-negative group reached as high as 1.69 times as that found in non-endemic areas. The positivity rate of egg-positive buffaloes was 100%, but was 30.3% in the endemic egg-negative group. Infected bovine antisera also recognized reSjc26GST, a 27kDa protein as determined by Western blot. These results suggest that the recombinant GST expressed in E. coli should be an effective diagnostic reagent for detection of antibody against S. japonicum in buffaloes. Due to straightforward production, excellent sensitivity and high specificity, the reSjc26GST described in this study can be considered as a candidate protein for immunological diagnosis of bovine schistosomiasis. Developing reSjc26GST, with its potential diagnostic values, will be useful for diagnosis and surveillance of schistosomiasis in controlling the spread of this parasitic disease in domestic animals.