Interleukin-9 blockage reduces early hepatic granuloma formation and fibrosis during Schistosoma japonicum infection in mice.

Hepatic fibrosis induced by schistosomes is regulated by a complex network of cytokines. T helper type 9 (Th9) cells are a new type of effector T helper cells, which mainly secrete the specific cytokine interleukin-9 (IL-9). Interleukin-9 has been shown to contribute to liver fibrosis in patients with chronic hepatitis B and in a mouse model due to carbon tetrachloride. However, the role of IL-9 in schistosomiasis fibrosis remains unknown. In this study, we investigated the roles of IL-9 in schistosomiasis through in vivo and in vitro studies. The in vivo studies found that neutralization of IL-9 reduced liver granulomatous inflammation and collagen deposition around parasite eggs. The in vitro studies found that the treatment of primary hepatic stellate cells with IL-9 induced a significant increase of collagen and α-smooth-muscle actin. Moreover, we also described the dynamics and relevance of IL-9 and IL-4 in mice infected with Schistosoma japonicum. We found that IL-9 might appear more quickly and at higher levels than IL-4. Hence, our findings indicated that IL-9 might play a role in regulating hepatic fibrosis in early-stage schistosomiasis and become a promising approach for regulating hepatic fibrosis caused by S. japonicum.

Mmu-miR-92a-2-5p targets TLR2 to relieve Schistosoma japonicum-induced liver fibrosis.

According to conservative estimates, >230 million people are infected with schistosomiasis,which becomes one of the most common parasitic diseases. This study focuses on investigating in vivo and in vitro effects of mmu-miR-92a-2-5p in Schistosoma japonicum-induced liver fibrosis by targeting TLR2. Through bioinformatic analysis, the overexpression of TLR2 and the down-regulation of mmu-miR-92a-2-5p were revealed in the progression of S. japonicum-induced liver fibrosis. BALB/C mice were taken advantage to construct normal control and schistosomiasis liver fibrosis (SLF) model. The mice in model groups were transfected recombinant lentivirus (Lenti-mmu-miR-92a-2-5p or Lenti-NC) to alter the expression of mmu-miR-92a-2-5p in vivo. HE and Masson staining were employed to observe the pathological changes and collagenous fibrosis. QRT-PCR showed that mmu-miR-92a-2-5p was decreased while TLR2 was elevated in the infected groups. However, lenti-mmu-miR-92a-2-5p group could inhibit liver fibrosis. Then the effect of mmu-miR-92a-2-5p on S. japonicum-induced liver fibrosis including cell apoptosis rates, proliferation and proteins related to liver fibrosis was examined in NIH-3T3 mouse embryonic fibroblasts. Moreover, the association between mmu-miR-92a-2-5p and TLR2 was detected by dual-luciferase reporter gene assay and the expression of cytokines IL-4, IFN-γ and TNF-α in SLF model was detected by ELISA. Further, the knockout of TLR2 in C57BL/6J mice was used to confirm the association between mmu-miR-92a-2-5p and TLR2. Thus, these findings demonstrated that mmu-miR-92a-2-5p inhibited S. japonicum-induced liver fibrosis by targeting TLR2 in vitro and in vivo.

[Preparation of recombinant retrovirus pRevTRE-E77.43 and its protective effect in a mouse model of Schistosoma japonicum infection].

OBJECTIVE: To explore the biological functions of E77.43, a gene segment of Microtus fortis, in treating Schistosoma japonicum infection. METHODS: Recombinant retroviral vectors of pRevTRE-E77.43 was constructed, and recombinant retroviral vectors were transfected into PA317 cells, and the stable cell lines were obtained by hygromycin screening, followed by the packaging, concentration and purification of recombinant retrovirus. The virus was transferred to the mice infected by S. japonicum via intravenous or intraperitoneal injection, through which the express of target gene and the treatment function in vivo were observed. RESULTS: The experiment showed the recombinant virus injected mice could efficiently express E77.43 on the 7th day after the injection which lasted for forty-five days thereafter. A significant reduction in adult worms (31.0%) and a high reduction (35.0%) in liver eggs were induced by pRevTRE-E77.43, while the reduction in adult worms and that in liver eggs was 1.2% and 0.9% induced by pRevTRE respectively (t = 3.524, 9.485, both P＜0.01). CONCLUSIONS: pRevTRE-E77.43 could be used for the treatment of S. japonicum infection, indicating that E77.43 may involve in the natural resistance of M. fortis to S. japonicum infection.

Adenovirus-mediated over-expression of Septin4 ameliorates hepatic fibrosis in mouse livers infected with Schistosoma japonicum.

Septin4 (Sept4) belongs to Septin family and may be involved in apoptosis, vesicle trafficking and other cell processes. In this study, we attempted to investigate the effect of Sept4 in hepatic fibrosis induced by Schistosoma japonicum. ICR mice infected with S. japonicum for 12weeks were treated with PBS, Ad-ctr and Ad-Sept4, respectively. All mice were killed at 2weeks after injection, and the changes in the fibrotic livers were detected via H&E staining, Sirius red staining, qRT-PCR, western blot and TUNEL analysis. In addition, pcDNA3.1-Sept4 plasmid was transfected into LX-2 cells to observe the effect of Sept4 on apoptosis of HSCs in vitro. Ad-Sept4 could ameliorate liver fibrosis, as detected by H&E staining and Sirius red staining. The number of TUNEL-positive cells was increased in the Ad-Sept4 treated group. The expression of Sept4 and cleaved-caspase-3 were all augmented, while the expression of α-SMA, Col1α1 and IL-13 were reduced in the Ad-Sept4 treated group, compared with that expressed in the Ad-ctr group. Over-expression of Sept4 in LX-2 cells could promote apoptosis of LX-2 cells in vitro. In conclusion, Ad-Sept4 can attenuate the development of liver fibrosis induced by S. japonicum through apoptosis.

Suppression of the Insulin Receptors in Adult Schistosoma japonicum Impacts on Parasite Growth and Development: Further Evidence of Vaccine Potential.

To further investigate the importance of insulin signaling in the growth, development, sexual maturation and egg production of adult schistosomes, we have focused attention on the insulin receptors (SjIRs) of Schistosoma japonicum, which we have previously cloned and partially characterised. We now show, by Biolayer Interferometry, that human insulin can bind the L1 subdomain (insulin binding domain) of recombinant (r)SjIR1 and rSjIR2 (designated SjLD1 and SjLD2) produced using the Drosophila S2 protein expression system. We have then used RNA interference (RNAi) to knock down the expression of the SjIRs in adult S. japonicum in vitro and show that, in addition to their reduced transcription, the transcript levels of other important downstream genes within the insulin pathway, associated with glucose metabolism and schistosome fecundity, were also impacted substantially. Further, a significant decrease in glucose uptake was observed in the SjIR-knockdown worms compared with luciferase controls. In vaccine/challenge experiments, we found that rSjLD1 and rSjLD2 depressed female growth, intestinal granuloma density and faecal egg production in S. japonicum in mice presented with a low dose challenge infection. These data re-emphasize the potential of the SjIRs as veterinary transmission blocking vaccine candidates against zoonotic schistosomiasis japonica in China and the Philippines.

Perforation of small bowel caused by Schistosoma japonicum: a case report.

A 67-year-old man from Jingzhou was admitted to the First Hospital Affiliated to Yangtze University in July 2013 with sudden onset of abdominal pain with dizziness for 12 h. The patient had sign of peritoneal irritation. Ultrasonography of the abdomen and pelvis showed hepatic fibrosis due to schistosomiasis. Computed tomography showed free gas in the peritoneal cavity. Plain abdominal radiography showed bilateral subdiaphragmatic accumulation of gas, perforation of the viscus, and radio-opacity in the left renal area. The patient underwent emergency exploratory laparotomy. At laparotomy, a moderate amount of muddy yellow pus was found in the intra-abdominal cavity. At the junction of the jejunum and ileum, about 250 cm from Treitz's ligament, there was an about 10-cm length of inflamed small bowel with perforation (3 mm in diameter) along the mesenteric border at the middle of the lesion. The patient underwent resection of the affected intestinal segment, along with end-to-end intestinal anastomosis. Histopathological examination revealed mucosal necrosis and hemorrhage with a large number of infiltrating eosinophils and neutrophils, and acute submucosal inflammation with a large number of infiltrating eosinophils and neutrophils associated with Schistosoma japonicum (S. japonicum) eggs. No intravascular adult parasite was found. Postoperatively, the patient was treated with praziquantel (30 mg/kg daily) for 4 d. The patient progressed well. To the best of our knowledge, this is the first case of small bowel perforation associated with eggs of S. japonicum.

[Diagnosis and treatment of schistosomiasis japonica-concensuses among ex- perts in Hunan, Hubei and Jiangxi provinces].

In order to further standardize the diagnosis and treatment of schistosomiasis japonica in China, on the basis of evidence-based medicine, the experts on schistosomiasis control from Hunan, Hubei and Jiangxi provinces summarized their consensuses on the disease after the discussion on the current situation and progress of clinical diagnosis and treatment of schistosomiasis in China, with the reference to the Diagnostic Criteria for Schistosomiasis (WS261-2006), which aimed to establish the therapeutic standards or guideline of schistosomiasis in China.

Guideline adherence for the treatment of advanced schistosomiasis japonica in Hubei, China.

This study compared physicians' practices on three treatment procedures and hospitalization days with guideline recommendations to assess guideline adherence in the treatment of advanced schistosomiasis japonica. Descriptive statistics were used to estimate patients' characteristics and rate of guideline adherence. And chi-square tests were used to assess influences of severity of the disease on guideline adherence. The study found no one (0/173) adhered to adequate diagnosis, treatment regimens, and discharge criteria of guidelines completely. And 2.23% of patients in group 1 and 4.23% in group 2 were totally conforming to adequate diagnosis. 91.91% of patients were conforming to adequate treatment regimens among which group 1 and group 2 were 90.32 and 92.25%, respectively. And one (2.23%) patient in group 1 and zero (0%) in group 2 were conforming to discharge criteria of guidelines, and most of the patients left hospital without symptom checks (151/173), liver function and biochemical tests (169/173), and complication checks (91/173). Among 173 inpatients, rate of adequate hospitalization days was 36.42% (63/173). And chi-square test suggested no significant difference (P > 0.05) on guideline adherence in two groups, which implied both of critical and general patients' treatments should be stressed to comply with guidelines. There existed a large gap between guidelines and practices of the treatment of advanced schistosomiasis japonica.

An integrated immunoproteomics and bioinformatics approach for the analysis of Schistosoma japonicum tegument proteins.

Schistosomiasis remains one of the major neglected tropical diseases (NTDs) causing morbidity of humans residing in the tropical countries. Much effort has been devoted to the development of vaccines, since it is recognized that vaccines can be served as an important supplementary component alongside chemotherapy for the future control and elimination of schistosomiasis. To accelerate digging new potential target antigens, it is essential to extensively and intensively search immunogenic proteins in a high-throughput manner using proteomics-microarray techniques. In the present study, an integrated immunoproteomics and bioinformatics approach was used to profile the tegument of the human blood fluke Schistosoma japonicum. Results showed that the full-length tegument proteins were high-throughput cloned and expressed and screened with sera from S. japonicum-infected patients and normal subjects using protein arrays. Here, thirty highly immunoreactive tegument proteins and 10 antigens with an AUC value greater than 0.90 were identified at first time. In particularly, STIP1, the highest immunoreactive tegument protein has been shown good antigenicity and immunogenicity, and thus makes it to be a potential target for designing anti-parasite drug or vaccine. BIOLOGICAL SIGNIFICANCE: The schistosome tegument plays a crucial role in host-parasite interactions and there are several tegument proteins that proved to be potential vaccine candidates. However, vaccines are not yet available, thus it is important to identify new target antigens from schistosome tegument proteome. Herein, we demonstrate that the S. japonicum tegument proteins were analyzed by an integrated immunoproteomics and bioinformatics approach. We found that thirty highly immunoreactive tegument proteins and 10 antigens with an AUC value greater than 0.90 were identified for the first time. In particularly, we found 17 of tegument immunoproteomes having putative interaction networks with other proteins of S. japonicum. The results will provide clues of potential target molecules for vaccine development and biomarkers for diagnostics of schistosomiasis.

Stem cell therapy for the treatment of parasitic infections: is it far away?

Stem cell therapy is an interventional treatment that introduces new cells into damaged tissues, which help in treating many diseases and injuries. It has been proved that stem cell therapy is effective for the treatment of cancers, diabetes mellitus, Parkinson's disease, Huntington's disease, cardiovascular diseases, neurological disorders, and many other diseases. Recently, stem cell therapy has been introduced to treat parasitic infections. The culture supernatant of mesenchymal stem cells (MSCs) is found to inhibit activation and proliferation of macrophages induced by the soluble egg antigen of Schistosoma japonicum, and MSC treatment relieves S. japonicum-induced liver injury and fibrosis in mouse models. In addition, transplantation of MSCs into naïve mice is able to confer host resistance against malaria, and MSCs are reported to play an important role in host protective immune responses against malaria by modulating regulatory T cells. In mouse models of Chagas disease, bone marrow mononuclear cell has been shown effective in reducing inflammation and fibrosis in mice infected with Trypanosoma cruzi, and transplantation of the bone marrow mononuclear cells prevents and reverses the right ventricular dilatation induced by T. cruzi infection in mice. Preliminary clinical trials demonstrate that transplantation of bone marrow derived-cells may become an important therapeutic modality in the management of end-stage heart diseases associated with Chagas disease. Based on these exciting results, it is considered by stating that it is firmly believed that, within the next few years, we will be able to find the best animal models and the appropriate stem cell type, stem cell number, injection route, and disease state that will result in possible benefits for the patients with parasitic infections, and stem cell therapy, although at an initial stage currently, will become a real therapeutic option for parasitic diseases.

[Investigation and treatment of newly discovered advanced schistosomiasis cases in Hunan Province in 2011].

OBJECTIVE: To understand the epidemiological characteristics and current status of newly confirmed advanced schistosomiasis patients in Hunan Province in 2011. METHODS: The cases previously diagnosed or suspected as advanced schistosomiasis in Hunan Province were the subjects of this investigation. Questionnairing (demographical information, disease history, etc.), clinical examination (ascites syndrome, abdominal palpation), laboratory examination, and abdominal ultrasonography were used to confirm the diagnosis. Treatment was given to the patients. RESULTS: In 2011, there were 620 newly discovered advanced schistosomiasis patients in Hunan Province, mainly distributed in Yueyang (300 cases, 48.4%), Changde (193 cases, 31.1%) and Yiyang (123 cases, 19.8%). The male-to-female ratio was 1.4:1. The average age of the patients was 60.4 +/- 12.4. 69.7% (432/620) of the patients were illiterate or with primary school education. 90.3% (560/620) of them were farmers. 162 (26.1%) cases were labour incapacity and 442 cases (71.3%) were with a weak labor ability before receiving medical treatment. The average time from discovery of schistosome infection to diagnosis of advanced schistosomiasis was (24.9 +/- 14.3) years. Among the 620 patients, 418 cases were with ascites (67.4%), 201 cases with splenomegaly (32.4%), and 1 case with multiple granuloma in the colon (0.2%). 172 cases (27.7%) were with visible abdominal vein, 144 cases (23.2%) with a hard liver texture, and 3.4% (21/620) cases with a hard spleen texture. Abdominal ultrasonography showed that 59.4% (368/620) of the patients were with grade III hepatic fibrosis. 577 cases (93.1%) received medical treatments and 43 cases (6.9%) received surgical treatment. After the treatment, the clinical symptoms and signs of 410 cases (66.1%) were improved and 210 cases (33.9%) needed further treatment. CONCLUSION: Newly confirmed advanced schistosomiasis patients in Hunan Province are mostly distributed in historically endemic areas, mainly middle-aged and older farmers, and generally in poor health when diagnosed.

Schistosoma japonicum calcium-binding tegumental protein SjTP22.4 immunization confers praziquantel schistosomulumicide and antifecundity effect in mice.

A family of platyhelminth tegument-specific proteins comprising of one or two calcium ion binding EF-hand and a dynein light chain-like domain, termed tegumental proteins, are considered as candidates of vaccine. In this study, we cloned and characterized SjTP22.4, a novel membrane-anchored tegumental protein in Schistosoma japonicum with theoretic MW of 22.4. The recombinant SjTP22.4 could be recognized by S. japonicum infected sera. Immunofluorescence revealed that this protein is not only located on the surface of tegument of adult and schistosomulum and cercaria, but also in the parenchymatous tissues and intestinal epithelium. Circular dichroism (CD) measurement demonstrated rSjTP22.4 had Ca(2+)-binding ability. The rSjTP22.4 vaccination without adjuvants produced comparable high level of antibody with that of immunization with adjuvants together indicated it was an antigen of strong antigenicity. The level of IgG1 is much higher than that of IgG2a and IgE is nearly negative in S. japonicum-infected and rSjTP22.4 immunized mice. In cercaria challenge experiment, mice vaccinated with SjTP22.4 showed no reduction in adult burden and egg production, comparing with the control mice, but 41% decrease in egg mature rate and 32% reduction in liver egg granuloma area. However, the SjTP22.4 immunized mice that received praziquantel treatment at 10d post infection caused 26% reduction in adult burden and 53% decrease in egg mature rate, comparing with the control mice only received praziquantel treatment. In conclusion, SjTP22.4 is a valuable vaccine candidate for S. japonicum of anti-pathogenesis and anti-transmission effect and plays a synergetic role in praziquantel to kill schistosomulum.

Mesenchymal stem cells relieve fibrosis of Schistosoma japonicum-induced mouse liver injury.

Mesenchymal stem cells (MSCs) have gained popularity for their potential as seed cells to treat various human diseases, including pathogenic infections. Schistosoma japonicum (S. japonicum) infection is characterized by formation of parasite egg granulomas and host liver fibrosis. MSCs have been proposed as useful treatments of S. japonicum infection, but the efficacy and underlying mechanisms remain unknown. Herein, we report that MSCs were able to ameliorate S. japonicum-induced liver injury in vivo and this effect was enhanced by combining MSCs with conventional drug praziquantel (PZQ). Kunming strains of mice were infected with S. japonicum and treated with vehicle, MSCs, PZQ or PZQ + MSCs. MSC treatment not only prolonged the survival time of infected mice but reduced egg granuloma diameter and decreased the concentrations of serum transforming growth factor-ß1 and hyaluronic acid. MSC treatment also inhibited collagen deposition and reduced the expression of collagen type 3, α-smooth muscle actin and vimentin in infected mouse liver tissues. Collectively, our findings suggest that MSC treatment represents a novel therapeutic approach for S. japonicum-induced liver injury and fibrosis.

[Recent investigation and treatment of 1 060 advanced schistosomiasis cases in Zhejiang Province].

OBJECTIVE: To understand the current status of advanced schistosomiasis patients, deliver medical treatment, and improve the case management in Zhejiang Province. METHODS: The cases previously diagnosed or suspected as advanced schistosomiasis in the province were the subjects of the investigation. Questionnairing (demographical information, disease history, etc.), clinical examination (ascites syndrome, abdominal palpation), laboratory examination (blood biochemistry, anti-Schistosoma japonicum antibody, eggs), and ultrasonography of the abdomen were used confirming the diagnosis. Treatment was given to the patients. RESULTS: There were 1 060 advanced schistosomiasis patients in 32 counties of 7 prefectures in the province. Majority of them distributed in water network regions, and lived with poor economic conditions. The average age of the patients was (66.3 +/- 9.3), with 89.3% ranged from 50 to 80 years old. Clinically 71.3% of the cases were with splenomegaly, 27.6% with ascites, 0.9% cases of multiple granuloma in the colon and 0.2% cases with dwarfism. 1 023 patients (96.5%) had received medical treatments. 69.4% of the cases had serious complications with advanced schistosomiasis and 52.5% had concurrently disorders in other systems. 71.1% of the patients had subjective symptoms and 65.2% had hepatosplenomegaly with hepatic fibrosis and dysfunction. The serum positive rate of anti-S. japonicum antibody was 15.7%. Stool hatching test and microscopy revealed no eggs in fecal samples, but 24 out of 38 cases were found metamorphic eggs by rectal biopsy. Three years' medical treatment improved the clinical conditions in 74.3% of the cases. CONCLUSION: Situation of the advanced schistosomiasis patients is quite critical. Treatment and care are urgently needed especially for those aged 50 to 80 years old. [

Schistosomiasis japonica identified by laparoscopic and colonoscopic examination.

A 45-year-old Philippine woman who came from Mindanao Island was admitted to our hospital with a complaint of epigastric discomfort. Abdominal ultrasonography and computed tomography demonstrated a network pattern and linear calcification in the liver. Laparoscopic examination showed numerous yellowish, small speckles over the liver surface. The liver surface was separated into many small blocks by groove-like depressions, demonstrating a so-called tortoise shell pattern. Conventional colonoscopy and narrow-band imaging showed irregular areas of yellowish mucosa, and diminished vascular network and increased irregular microvessels extending from the descending colon to the rectum. Liver biopsy showed many Schistosoma japonicum eggs in Glisson's capsule and colon biopsy showed many S. japonicum eggs in the submucosal layer. These findings established a diagnosis of schistosomiasis japonica. The present case is imported schistosomiasis japonica. Even though new cases have not occurred recently in Japan, we should remain aware of schistosomiasis japonica for patients who came from foreign epidemic areas.

A cluster-randomised intervention trial against Schistosoma japonicum in the Peoples' Republic of China: bovine and human transmission.

BACKGROUND: Zoonotic schistosomiasis japonica is a major public health problem in China. Bovines, particularly water buffaloes, are thought to play a major role in the transmission of schistosomiasis to humans in China. Preliminary results (1998-2003) of a praziquantel (PZQ)-based pilot intervention study we undertook provided proof of principle that water buffaloes are major reservoir hosts for S. japonicum in the Poyang Lake region, Jiangxi Province. METHODS AND FINDINGS: Here we present the results of a cluster-randomised intervention trial (2004-2007) undertaken in Hunan and Jiangxi Provinces, with increased power and more general applicability to the lake and marshlands regions of southern China. The trial involved four matched pairs of villages with one village within each pair randomly selected as a control (human PZQ treatment only), leaving the other as the intervention (human and bovine PZQ treatment). A sentinel cohort of people to be monitored for new infections for the duration of the study was selected from each village. Results showed that combined human and bovine chemotherapy with PZQ had a greater effect on human incidence than human PZQ treatment alone. CONCLUSIONS: The results from this study, supported by previous experimental evidence, confirms that bovines are the major reservoir host of human schistosomiasis in the lake and marshland regions of southern China, and reinforce the rationale for the development and deployment of a transmission blocking anti-S. japonicum vaccine targeting bovines. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12609000263291.

Conquering 'snail fever': schistosomiasis and its control in China.

Schistosomiasis japonica is a serious parasitic disease and a major health risk for more than 60 million people living in the tropical and subtropical zones of south China. The disease is a zoonosis and its cause, the parasitic trematode Schistosoma japonicum, has a range of mammalian reservoirs, making control efforts difficult. Current control programs are heavily based on community chemotherapy with a single dose of the highly effective drug praziquantel. However, vaccines (for use in bovines and in humans) in combination with other control strategies are needed to eliminate the disease. In this review, we provide an overview of the transmission, clinical features, pathogenesis, diagnosis, treatment, genetics and susceptibility, epidemiology, and prospects for control of schistosomiasis japonica in China. The threat posed by the Three Gorges Dam may undermine control efforts because it will change the local ecology and associated schistosomiasis transmission risks over the next decade and beyond.

Spinal cord schistosomiasis japonica: a report of 4 cases.

BACKGROUND: Neuroschistosomiasis is a severe presentation of schistosomal infection. Currently however, spinal cord schistosomiasis japonica is clinically rare, and very few cases are reported. METHODS: The purpose of this study is to retrospectively analyze the diagnosis and treatment of 4 patients who presented with a lower cord syndrome of acute progression characterized by motor, sensory, and autonomic dysfunctions. The patients were examined by MRI, and the biochemical and immunologic changes of blood and CSF of the patients were also analyzed before surgery. Treatments including surgical resection and antischistosomal drugs followed by a histologic examination were used to confirm the diagnosis. RESULTS: Spinal cord schistosomiasis japonica is a very rare disease. Magnetic resonance imaging can obtain precise position fixing, although it is hard to make preoperative qualitative determination. Postoperative follow-up assessment indicated that the symptoms of 4 patients had improved without further treatment. CONCLUSIONS: The main clinical manifestations of spinal cord schistosomiasis japonica have some common features, and MRI is useful and important in diagnosing the disease. The most effective treatment for the disease that shows radiological evidence of spinal cord or conus compression and inefficacious expectant treatment by other methods is to excise it totally and apply antischistosomal drugs.

[Studies on mechanism of protective immunity against infection of Schistosoma japonicum induced by Sj26 gene transfected dendritic cell].

OBJECTIVE: To explore the mechanism of protective immunity against Schistosoma japonicum infection induced by Sj26 gene transfected dendritic cell (DC). METHODS: 48 BALB/c mice were divided randomly into 4 groups with 12 each. The mice were injected through auricle for three times with Sj26 gene transfected DC (Group A), pcDNA3 transfected DC (Group B), untreated DC (Group C) and RPMI-1640 (Group D) respectively, and challenged with 40+/-2 cercariae of S. japonicum per mouse 2 weeks after the last immunization. Sera from mice were examined for IgG antibody, IFN-gamma and IL-4 by ELISA. Western blot was used for detecting specific anti-Sj26 IgG antibody. The production of IFN-gamma and IL-4 in the supernatant of spleen cells stimulated with soluble egg antigen (SEA) and ConA was quantified by sandwich ABC-ELISA. The proliferation of spleen cells were measured with MTT method. RESULTS: IgG antibody increased significantly in the mice of group A at 2 weeks after the last immunization (absorbency A491=0.117), higher than that of group B (A491=0.061) and group C (A491=0.058) (P<0.05). The Mr 26000 antigen of S. japonicum was strongly recognized by sera from group A by Western blot. The level of IL-4 in mice of each group showed no significant difference before and after immunization. The level of IFN-gamma in group A (101.4+/-4.9 pg/ml) was significantly higher than that before immunization (15.0+/-1.9 pg/ml) and that of group B (40.1+/-3.1 pg/ml) and group C (35.6+/-1.2 pg/ml) (P<0.01). The level of IFN-gamma in spleen cells from group A in response to ConA and SEA (171.2 and 70.8 pg/ml, respectively) was higher than that of group D (91 and 49.7 pg/ml, respectively) (P<0.01). The level of IL-4 in spleen cells from group A in response to ConA and SEA (79.7 and 50.7 pg/ml, respectively) was lower than that of group D (125.2 and 70.5 pg/ml, respectively) (P<0.01). The stimulating index of spleen cells from group A was 4.1 and 2.82 in response to ConA and SEA respectively, higher than that of other groups (compared with group D, P<0.05). CONCLUSION: Sj26 gene transfected dendritic cell induces predominant Th1 type immune response which might play a role in protection against S. japonicum infection.

Comparison of the role of dendritic cells and macrophages in inducing protective immunity against Schistosoma japonicum.

OBJECTIVE: To compare a potential role of dendritic cells (DCs) and macrophages in inducing protective immunity against infection with Schistosoma japonicum. METHODS: DCs and macrophages were pulsed in vitro with soluble egg antigen (SEA) of S. japonicum. BALB/c mice were injected three times with DCs or macrophages, either antigen-pulsed or not, and challenged with 40 +/- 2 cercariae of S. japonicum per mouse. Worms were collected 42 days later by portal perfusion of the mice and egg number of liver was calculated. To evaluate whether protective immunity had been induced by preparations of DCs or macrophages, the worm burden and fertility (eggs per female per mouse liver) were compared between the groups of mice. The antibody level against SEA was detected by ELISA. RESULTS: With respect to mice injected with untreated cells, numbers of worms and eggs per female worms were significantly reduced in the groups of mice having received pulsed DCs (26. 3% and 37.9%, respectively), or pulsed macrophages (22.0% and 30.7%). Untreated DCs and macrophages induced no significant effects. The antibody level against SEA rose in sera of all groups of mice up to 42 days after the challenge, but most pronounced in those immunized with pulsed DCs, although this was not significantly different from other groups. CONCLUSION: The results suggest that the protective immunity against S. japonicum might be induced by DCs to a higher extent than by macrophages after in vitro pulsing with egg antigen.