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Great achievements have been gained in schistosomiasis control in China due to the last half-century endeavor. These achievements not only indicate the success in disease control, but also represent a particularly successful social practice with a unique cultural property. Inspite of the accumulating reports on schistosomiasis prevention and control experience, there is a need to sublimate the experience to the "cultural" level, as historically the value of cultural and spiritual merits goes far beyond that of the achievements. Although the strategy and technology will be enriched with time, the cultural spirit remains especially important for the long- term promotion of schistosomiasis control. This paper materially dissected the meaning of "China's culture for schistosomiasis control", i.e., people-first, government-oriented, science-respected, collective wisdom and efforts, and diversity-embracing.

Although the number of human infections decreased, human prevalence increased from 4.9% in 1995 to 5.1% in 2004., Results from the third nationwide cluster sampling survey on the epidemiology of schistosomiasis in the People’s Republic of China, conducted by the Ministry of Health in 2004, are presented. A stratified cluster random sampling technique was used, and 239 villages were selected in 7 provinces where Schistosoma japonicum remains endemic. A total of 250,987 residents 6–65 years of age were included in the survey. Estimated prevalence rates in the provinces of Hunan, Hubei, Jiangxi, Anhui, Yunnan, Sichuan, and Jiangsu were 4.2%, 3.8%, 3.1%, 2.2%, 1.7%, 0.9%, and 0.3%, respectively. The highest prevalence rates were in the lake and marshland region (3.8%) and the lowest rates were in the plain region with waterway networks (0.06%). Extrapolation to all residents in schistosome-endemic areas indicated 726,112 infections. This indicates a reduction of 16.1% compared with a nationwide survey conducted in 1995. However, human infection rates increased by 3.9% in settings where transmission is ongoing.

T-cell activation requires T-cell receptor (TCR) signaling and a second signal called costimulation. This article overviewes the research progress of the effect of costimulatory signals in schistosome infection.

To investigate the antibody response to leucine aminopeptidase in the different stages of Schistosoma japonicum infection.The expression product of SjLAP was identified by Western blot and further purified by using nickel column. The IgG levels in the response to SjLAP in murine and porcine sera were detected by ELISA at different time points after the infection of S. japonicum.SjLAP expressed by E. coli was recognized by anti-his monoclonal antibody and S. japonicum-infected mice sera by Western blot. The results of ELISA showed that IgG responses to SjLAP rose gradually and reached the peak at 4 weeks post-infection for pigs (P1) and 6 weeks post-infection for mice (P2). With the appearance of a large number of eggs in the tissue, SjLAP-specific IgG levels were significantly down-regulated ( P1 = 0. 0004, P2 = 0. 0001).SjLAP originated from the adult worm might become a potential target for early diagnosis of schistosomiasis japonica.

The authors, in this paper, has briefly looked back the developmental history of human parasitology, which, as an independent discipline, was established in late 19th century and early 20th century. In the process, it underwent an early height of development, then met with setback and relative decline. Since 70s-80s of last century, the introduction and application of new theory of modern biology, especially advanced biotechniques to parasitology has led to a striking development in many fields of the discipline, leading to deeper understanding of parasite-host interplay as well as providing new ideals and tools for disease control. The authors also stressed that nowadays the discipline is still relatively isolated from the mainstream of modern biologic research and is still neglected by scientific community and medical education in the world, though it still is one of the major problems in public health, particularly in developing world including China. To argue the currently neglected situation of parasitology, especially in medical education, the authors emphasized the continuing requirements for the discipline and reflected on the developmental strategy of parasitology to meet the coming challenges and opportunities for further development.

Great progress has been made on vaccine research for schistosomiasis, including those on immune mechanism and Schistosoma genome which have made active effect to vaccine development. This paper reviews the progress on the candidate vaccine antigens including protein vaccine, DNA vaccine and multivalent vaccine against Schistosoma japonicum.

Background and Aim: To investigate a possible association between HLA genes with serum alanine aminotransferase (ALT) levels and evaluate whether the HLA-DQA1, DQB1, and DRB1 genes could influence the development of liver damage in chronic hepatitis C. Methods: A total of 145 patients with chronic hepatitis C virus (HCV) infection (36 patients with persistently normal ALT values; 109 patients with elevated ALT levels) and 160 uninfected healthy controls were examined for HLA-DQA1, DQB1, and DRB1 molecules by using polymerase chain reaction–sequencing based typing (PCR-SBT). Results: Among the patients chronically infected with HCV, the frequencies of DQA1*0501, DQB1*0301, and DRB1*0401 alleles were significantly increased in the normal ALT group compared with those with abnormal ALT levels, whereas that of DQB1*0201 was significantly lower. As compared to uninfected healthy controls, DQA1*0501, DQB1*0301, and DRB1*0401 allele frequencies were also statistically higher in the normal ALT group, whereas that of DQB1*0201 was the inverse. The haplotype frequencies of DQA1*0301-DQB1*0301, DQA1*0501-DQB1*0301, and DRB1*1101-DQB1*0301 were found to be significantly higher in the normal ALT group. Multivariate logistic regression indicated that female sex, and the DQB1*0301 allele and DRB1*0401 allele were independently associated with normal ALT values, whereas DQB1*0201 allele was the inverse. Conclusions: These results suggest that particular HLA alleles may have an influence on the serum ALT level of chronic HCV infection as a host genetic factor in the Chinese population. The DQA1*0501, DQB1*0301, and DRB1*0401 alleles, and the DQA1*0301-DQB1*0301, DQA1*0501-DQB1*0301, and DRB1*1101-DQB1*0301 haplotypes seem to be associated with low hepatitis activity; whereas DQB1*0201 allele is closely correlated with the progression of liver injury in chronic HCV infection.

To characterize the immune responses including local and systemic immunity induced by infection with H pylori, especially with CagA+ H pylori strains and the underlying immunopathogenesis.A total of 711 patients with different gastric lesions were recruited to determine the presence of H pylori infection and cytotoxin associated protein A (CagA), the presence of T helper (Th) cells and regulatory T (Treg) cells in peripheral blood mononuclear cells (PBMCs), expression of plasma cytokines, and RNA and protein expression of IFN-gamma and IL-4 in gastric biopsies and PBMCs were determined by rapid urease test, urea [(14)C] breath test, immunoblotting test, flow cytometry , real time RT-PCR and immunohistochemistry.Of the patients, 629 (88.47%) were infected with H pylori; 506 (71.16%) with CagA+ and 123 (17.30%) with CagA- strains. Among patients infected with CagA+ H pylori strains, Th1-mediated cellular immunity was associated with earlier stages of gastric carcinogenesis, while Th2-mediated humoral immunity dominated the advanced stages and was negatively associated with an abundance of Treg cells. However, there was no such tendency in Th1/Th2 polarization in patients infected with CagA- H pylori strains and those without H pylori infection.Polarization of Th cell immune responses occurs in patients with CagA+ H pylori infection, which is associated with the stage and severity of gastric pathology during the progression of gastric carcinogenesis. This finding provides further evidence for a causal role of CagA+ H pylori infection in the immunopathogenesis of gastric cancer.

To investigate the polymorphism of HLA-DQA1 and DQB1 genes of Han population in Jiangsu of China.The alleles and haplotypes frequencies of HLA-DQA1 and DQB1 genes in 100 unrelated healthy individuals were analyzed by using polymerase chain reaction-sequence-based typing (PCR-SBT).Among the 7 DQA1 alleles detected, the most common allele was DQA1*0301/02/03 with a frequency of 29.5%, which was followed by DQA1*0501, DQA1*0102 and DQA1*0201 with frequencies of 18.5%, 17.0% and 12.5%, respectively. Of the 13 DQB1 alleles detected, DQB1*0201/02 allele (21.5%) was the most frequent allele, followed by DQB1*0301/09 (14.5%), DQB1*0303 (13.5%) and DQB1*0603 (11.5%). The most common DQA1 vs DQB1 haplotype was DQA1*0301/02/03 vs DQB1*0303 with a frequency of 12.5%, which was followed by the DQA1*0201-DQB1*0201/02 (10.5%),DQA1*0501-DQB1*0201/02 (9.5%) and DQA1*0501-DQB1*0301/09 (7.0%).The distribution of HLA-DQ alleles and haplotypes in Jiangsu Han population shares some genetic characteristics with other population in northern of China, but has its own characteristics. The data will provide useful information for anthropology, organ transplantation and disease association studies.

To better understand the interaction between Schistosoma japonicum and its murine host, we characterized the immune response of CD4+ T cells generated during an experimental S. japonicum infection based on different key aspects, from gene expression to cell behavior. Mouse oligonucleotide microarrays were used to compare gene expression profiles of CD4+ T cells from spleens of mice at 0, 3, 6 and 13 weeks post-infection. Flow cytometry analysis was used to determine type 1 and type 2 cytokine-secreting CD4+ T cells, to test apoptosis of CD4+ T cells and to count CD4+CD25+ T cells, a kind of regulatory subpopulation of CD4+ T cells. The percentage of interleukin-4-producing CD4+ T cells was found to be much higher than that of gamma-interferon-producing cells, especially after stimulation with S. japonicum egg antigen, which was consistent with type 1 and type 2 cytokine gene expression in the genechip. Microarray data also showed that S. japonicum induced the increased expression of Th2 response-related genes, whereas some transcripts related to the Th1 responsive pathway were depressed. Flow cytometry analysis showed a marked increase in the apoptotic CD4+ T cells from 6 weeks post-infection and in the ratio of CD4+CD25+ to CD4+ T cells in infected mice after 13 weeks. We therefore concluded that experimental infection of mice with S. japonicum resulted in a Th2-skewed immune response, which was to a great extent monitored by the immune regulatory network, including cytokine cross-modulation, cell apoptosis and the subpopulation of regulatory cells.

CD4+CD25+ T cells play a major role in modulating immune response, but few reports have been published about schistosomiasis. Here, we investigated the changes in CD4+CD25+ T cell populations in spleens and mesenteric lymph nodes of mice infected with Schistosoma japonicum. The proportions of CD4+CD25+ T cells in total CD4+ T cells were analyzed by flow cytometry. CD25 and Foxp3 expression was measured by real-time quantitative polymerase chain reaction. The suppressive activities of CD4+CD25+ T cells were detected by in vitro proliferation of splenocytes. Evidence showed that the percentage of CD4+CD25+ T cells was the same as controls 3 weeks post-infection. At the acute stage of infection, the percentage decreased significantly. However, at the chronic stage of infection, it rebounded to normal levels or even higher. The expression of the CD25 and Foxp3 showed gradual increase along with the infection progress. In vitro experiment also showed the strong suppressive effect of CD4+CD25+ T cells, isolated during the chronic stage, on proliferation of the CD25- splenocytes. This is the first time that the dynamics of CD4+CD25+ T cell populations was demonstrated in mice infected with schistosomiasis. In conclusion, our data indicated that CD4+CD25+ cells might be involved in the immune modulation during S. japonicum infection, which enhances current knowledge of the mechanisms of the immuno-downregulation and re-infection in schistosomiasis.

To assess the associations of human leukocyte antigen (HLA) class II DQB1*0301 and/or DRB1*1101 allele with spontaneous hepatitis C virus (HCV) clearance by meta-analysis of individual dataset from all studies published till date.To clarify the impact of HLA class II polymorphisms on viral clearance, we performed a meta-analysis of the published data from 11 studies comparing the frequencies of DQB1*0301 and DRB1*1101 alleles in individuals with spontaneous resolution to those with persistent infection. As we identified the heterogeneity between studies, summary statistical data were calculated based on a random-effect model.Meta-analyses yielded summary estimates-odds ratio (OR) of 2.36 [95%CI (1.62, 3.43), P0.00001] and 2.02 [95%CI (1.56, 2.62), P0.00001] for the effects of DQB1*0301 and DRB1*1101 alleles on spontaneous clearance of HCV, respectively.These results support the hypothesis that specific HLA class II alleles might influence the susceptibility or resistance to persistent HCV infection. Both DQB1*0301 and DRB1*1101 are protective alleles and present HCV epitopes more effectively to CD4(+)T lymphocytes than others, and subjects with these two alleles are at a lower risk of developing chronic HCV infection. Large, multi-ethnic confirmatory and well-designed studies are needed to determine the host genetic determinants of HCV infection.

Th1-type cytokines produced by the stimulation of Th1-type epitopes derived from defined schistosome-associated antigens are correlated with the development of resistance to the parasite infection. Schistosoma mansoni 28 kDa glutathione-S-transferase (Sm28GST), a major detoxification enzyme, has been recognized as a vaccine candidate and a phase II clinical trial has been carried out. Sheep immunized with recombinant Schistosoma japonicum 28GST (Sj28GST) have shown immune protection against the parasite infection. In the present study, six candidate peptides (P1, P2, P3, P4, P7 and P8) from Sj28GST were predicted, using software, to be T cell epitopes, and peptides P5 and P6 were designed by extending five amino acids at the N-terminal and C-terminal of P1, respectively. The peptide 190-211 aa in Sj28GST corresponding to the Th1-type epitope (190-211 aa) identified from Sm28GST was selected and named P9. The nine candidate peptides were synthesized or produced as the fusion protein with thioredoxin in the pET32c(+)/BL21(DE3) system. Their capacity to induce a Th1-type response in vitro was measured using lymphocyte proliferation, cytokine detection experiments and flow cytometry. The results showed that P6 (73-86 aa) generated the strongest stimulation effect on T cells among the nine candidate peptides, and drove the highest level of IFN-gamma and IL-2. Therefore, P6 is a functional Th1-type T cell epitope that is different from that in Sm28GST, and will be useful for the development of effective vaccines which can trigger acquired immunity against S. japonicum. Moreover, our strategy of identifying the Th1-type epitope by a combination of software prediction and experimental confirmation provides a convenient and cost-saving alternative approach to previous methods.

Vaccination with ultraviolet-attenuated cercariae of Schistosoma japonicum induced protective immunity against challenge infection in experimental animal models. Our preliminary study on the transcription levels of IFN-gamma and IL-4 in splenic CD4+ T cells revealed that attenuated cercariae elicited predominantly a Th1 response in mice at the early stage, whereas normal cercariae stimulated primarily Th2-dependent responses. Further analysis on the gene profile of the skin-draining lymph nodes demonstrated that the levels of IFN-gamma were significantly higher in vaccinated mice than those in infected mice at day 4, 7 and 14 post-vaccination or post-infection. However, for IL-12 and IL-4, the potent inducers of Th1 and Th2 responses, respectively, as well as IL-10, there were no differences over the course of the experiment between the infected and vaccinated mice. To explore the underlying factors that may potentially contribute to elevated IFN-gamma in vaccinated mice, the mRNA profiles of the skin-draining lymph nodes at day 4 post-exposure were compared using oligonucleotide microarrays. Within the 847 probe sets with increased signal values, we focused on chemokines, cytokines and relevant receptors, which were validated by semi-quantitative RT-PCR. A comprehensive understanding of the immune mechanisms of attenuated cercariae-induced protection may contribute to developing efficient vaccination strategies against S. japonicum, especially during the early stage of infection.

To investigate the molecular characteristic of interferon-gamma mediating protective immunity against schistosomiasis japonica in mice.CD4+ T cells were isolated from spleens of mice infected with Schistosoma japonicum at different time-points. The cDNA microarray technique combined with RT-PCR was used to explore IFN-gamma inducible GTPase family gene expression profile of CD4+ T cell. IGTP, a representative IFN-gamma, inducible GTPase having vital anti-infection activity, was amplified from spleen of BALB/c mice using RT-PCR, then cloned into pGEM(r)-T easy vector for sequencing.IFN-gamma inducible GTPase family had the similar characteristic over the course of S. japonicum infection. The gene expression of these members were up-regulated or had little change at 3 wk post-infection, then down-modulated from 6 wk to 13 wk post-infection, which was also confirmed by RT-PCR. As for IGTP, two inserts were identified after sequencing. One was 142 bp shorter than another, but the fragment was lost due to low annealing temperature.There is a dramatic inhibition of IFN-gamma pathway and IFN-gamma-dependent anti-infective immunity during the infection of S. japonicum.

To predict T-cell epitopes of recombinant schistosoma japonicum 28 kDa glutathione-S-transferase(GST) with software and identify the Th1 type T-cell epitopes by experiments.T-cell epitopes of recombinant schistosoma japonicum 28kDa GST were predicted with software and several epitopic candidates were screened from them according to their scores. Some of the epitopic candidates were synthesized and the other epitope peptides fused with thioredoxin(Trx) were expressed in E.coli BL21(DE3) and purified by Ni(+) column affinity chromatography. C57BL/6 (H-2(b)) mice's were immunized via peritoneal infection with ultraviolet ray irradiated-cercariae and then boosted with recombinant schistosoma japonicum 28 kDa GST. The immunized mice splenocytes were prepared, cultured and stimulated with synthesized epitope peptides and epitope peptide fusion proteins, respectively. Stimulation activity of synthesized epitope peptides and epitope peptides fusion proteins were assayed by lymphocyte proliferation assay. Levels of IFN-gamma and IL-2 were measured by ELISA. CD4(+) T cells and T cells secreting IFN-gamma and IL-4 were detected by flow cytometry.Epitope P6(73-86aa) among 9 epitopic candidates could generate the strongest stimulation effect on splenocytes, stimulate secretion of higher levels of IFN-gamma and IL-2, and induce more IFN-gamma(+) and IL-4 (+) T cells.The recombinant 28 kDa GST possesses functional Th1 type T-cell epitope.

To identify the T cell epitopes on 22.6 kDa antigen of Schistosoma japonicum (Sj22.6).The primary structure of Sj22.6 molecule was analysed using various predictive algorithms and a panel of 4 peptides were acquired. Their oligonucleotides were designed, synthesized and inserted into the multiple cloning site of plasmid pET-32c(+). The recombinant plasmids were transformed into E. coli BL21 and identified by endonuclease digestion and sequencing. The positive clones containing the recombinant plasmids could express specific fusion proteins (trx-epitope, MW approximately 20 kDa) induced by IPTG. The fusion protein with 6 x His could be coupled with NTA resin specifically, and purified by elusion of the column with buffer containing imidazole. The purified fusion proteins were incubated with splenocytes of C3H mice and then, the proliferation of splenocytes was determined by 3H-TdR incorporation assay.The recombinant plasmids were constructed successfully and the positive clones containing the recombinant plasmids expressed specific fusion proteins. Three of the purified fusion proteins (P4, P5, P6) could stimulate the lymphocyte proliferation.Three T cell epitopes on Sj22.6 antigen were identified.

To purify the specific IgE antibody-related recombinant protein of Schistosoma japonicum and to identify its immunogenicity.The recombinant plasmid Sj43B/pGEX-6p-1 was expressed in E. coli BL 21. The inclusion body of the fusion protein was washed by TNMFX buffer and separated by FPLC. After renaturation, the fusion protein was used to vaccinate the mice. The specific IgG and IgE antibodies were detected by dot-ELISA and Western blotting analysis, respectively.Most of the proteins mixed with the inclusion body of the recombinant protein could be eliminated by washing with TNMFX buffer. The purified recombinant fusion protein could be obtained by FPLC separation. The experiment on mice immunized with the fusion protein showed that the specific IgE antibody was generated against the target part of the fusion protein, but not the specific IgG antibody.The fusion protein expressed by the recombinant plasmid Sj43B/pGEX-6p-1 could induce specific IgE response of the immunized mice.

To identify the epitopes of 22.6 kDa antigen of Schistosoma japonicum (Sj22.6).A 12-mer library displayed on pIII of fd phage was used to screen the epitopes of Sj22.6 with the purified multiple clone IgG antibody against the Sj22.6 antigen. Five rounds of biopanning were carried out and fourteen clones from the fifth round biopanning were randomly selected and identified by Western blotting. The mice were immunized with the obtained positive clones and the antibody titers of sera from the mice were detected. The clones which could stimulate the mice to produce anti-Sj22.6 antibodies were sequenced and their amino acid sequences were compared with that of Sj22.6.Six clones selected from the fourteen ones could stimulate the mice to produce anti-Sj22.6 antibodies analysed by Western blotting. The amino acid sequence of one epitope showed high homology with Sj22.6.Four epitopes of Sj22.6 were obtained. One may be a structure epitope and the other three were mimic epitopes.