A Praziquantel Treatment Study of Immune and Transcriptome Profiles in Schistosoma haematobium-Infected Gabonese Schoolchildren.

BACKGROUND: Although Schistosoma haematobium infection has been reported to be associated with alterations in immune function, in particular immune hyporesponsiveness, there have been only few studies that have used the approach of removing infection by drug treatment to establish this and to understand the underlying molecular mechanisms. METHODS: Schistosoma haematobium-infected schoolchildren were studied before and after praziquantel treatment and compared with uninfected controls. Cellular responses were characterized by cytokine production and flow cytometry, and in a subset of children RNA sequencing (RNA-Seq) transcriptome profiling was performed. RESULTS: Removal of S haematobium infection resulted in increased schistosome-specific cytokine responses that were negatively associated with CD4+CD25+FOXP3+ T-cells and accompanied by increased frequency of effector memory T-cells. Innate responses to Toll like receptor (TLR) ligation decreased with treatment and showed positive association with CD4+CD25+FOXP3+ T-cells. At the transcriptome level, schistosome infection was associated with enrichment in cell adhesion, whereas parasite removal was associated with a more quiescent profile. Further analysis indicated that alteration in cellular energy metabolism was associated with S haematobium infection and that the early growth response genes 2 and 3 (EGR 2 and EGR3), transcription factors that negatively regulate T-cell activation, may play a role in adaptive immune hyporesponsiveness. CONCLUSIONS: Using a longitudinal study design, we found contrasting effects of schistosome infection on innate and adaptive immune responses. Whereas the innate immune system appears more activated, the adaptive immunity is in a hyporesponsive state reflected in alterations in CD4+CD25+FOXP3+ T-cells, cellular metabolism, and transcription factors involved in anergy

Enhanced Pro-Inflammatory Cytokine Responses following Toll-Like-Receptor Ligation in Schistosoma haematobium-Infected Schoolchildren from Rural Gabon

BACKGROUND: Schistosoma infection is thought to lead to down-regulation of the host's immune response. This has been shown for adaptive immune responses, but the effect on innate immunity, that initiates and shapes the adaptive response, has not been extensively studied. In a first study to characterize these responses, we investigated the effect of Schistosoma haematobium infection on cytokine responses of Gabonese schoolchildren to a number of Toll-like receptor (TLR) ligands. METHODOLOGY: Peripheral blood mononuclear cells (PBMCs) were collected from S. haematobium-infected and uninfected schoolchildren from the rural area of Zile in Gabon. PBMCs were incubated for 24 h and 72 h with various TLR ligands, as well as schistosomal egg antigen (SEA) and adult worm antigen (AWA). Pro-inflammatory TNF-alpha and anti-inflammatory/regulatory IL-10 cytokine concentrations were determined in culture supernatants. PRINCIPAL FINDINGS: Infected children produced higher adaptive IL-10 responses than uninfected children against schistosomal antigens (72 h incubation). On the other hand, infected children had higher TNF-alpha responses than uninfected children and significantly higher TNF-alpha to IL-10 ratios in response to FSL-1 and Pam3, ligands of TLR2/6 and TLR2/1 respectively. A similar trend was observed for the TLR4 ligand LPS while Poly(I:C) (Mda5/TLR3 ligand) did not induce substantial cytokine responses (24 h incubation). CONCLUSIONS: This pilot study shows that Schistosoma-infected children develop a more pro-inflammatory TLR2-mediated response in the face of a more anti-inflammatory adaptive immune response. This suggests that S. haematobium infection does not suppress the host's innate immune system in the context of single TLR ligation

Cytokine Responses to Schistosoma mansoni and Schistosoma haematobium in Relation to Infection in a Co-endemic Focus in Northern Senegal

Background In Africa, many areas are co-endemic for the two major Schistosoma species, S. mansoni and S. haematobium. Epidemiological studies have suggested that host immunological factors may play an important role in co-endemic areas. As yet, little is known about differences in host immune responses and possible immunological interactions between S. mansoni and S. haematobium in humans. The aim of this study was to analyze host cytokine responses to antigens from either species in a population from a co-endemic focus, and relate these to S. mansoni and S. haematobium infection. Methodology Whole blood cytokine responses were investigated in a population in the north of Senegal (n = 200). Blood was stimulated for 72 h with schistosomal egg and adult worm antigens of either Schistosoma species. IL-10, IL-5, IFN-γ, TNF-α, and IL-2 production was determined in culture supernatants. A multivariate (i.e. multi-response) approach was used to allow a joint analysis of all cytokines in relation to Schistosoma infection. Principal Findings Schistosoma haematobium egg and worm antigens induced higher cytokine production, suggesting that S. haematobium may be more immunogenic than S. mansoni. However, both infections were strongly associated with similar, modified Th2 cytokine profiles. Conclusions/Significance This study is the first to compare S. mansoni and S. haematobium cytokine responses in one population residing in a co-endemic area. These findings are in line with previous epidemiological studies that also suggested S. haematobium egg and worm stages to be more immunogenic than those of S. mansoni.status: publishe

Th17 cells are associated with pathology in human schistosomiasis (43.24)

Abstract Infection with parasitic helminths of the genus Schistosoma results in a wide range of immunopathology. Studies in murine schistosomiasis suggest that Th17 cells play a major role in the development of severe pathology; conversely, regulatory T (Treg) cells represent a mechanism to curtail excessive inflammation. We assessed by flow cytometry the profile of peripheral blood (PB) CD4 T cells in a cohort of children with urinary schistosomiasis from the village of Pakh, Department of Richard Toll, Senegal. S. hematobium-infected children with bladder pathology had a significantly higher percentage of PB IL-17+ cells with higher RORγt+/ Foxp3+ and IL-17+/ IL-10+ cell ratios than infected children without pathology. To investigate the relationship between PB values and target organs, we also examined the PB T cell response in murine S. mansoni infection (S. hematobium is non-permissive in mice) and, similar to humans, found a significantly higher percentage of CD4+ IL-17+ cells in high-pathology CBA mice than in low-pathology BL/6 mice. Moreover, a significant increase in IL-17+ cells in spleen and liver granulomas together with lower Foxp3+ cells in the spleen of CBA mice denoted a good correlation between PB and target organs. Our findings for the first time demonstrate an association between pathology and PB Th17 cells in human schistosomiasis and suggest human PB T cell subsets to faithfully reflect those mediating lesions in organs affected by the disease.</jats:p

Schistosoma mansoni schistosomula antigens induce Th1/Pro-inflammatory cytokine responses.

Larvae of Schistosoma (schistosomula) are highly susceptible to host immune responses and are attractive prophylactic vaccine targets, although cellular immune responses against schistosomula antigens in endemic human populations are not well characterized. We collected blood and stool from 54 Schistosoma mansoni-infected Ugandans, isolated peripheral blood mononuclear cells and stimulated them for 24 hours with schistosome adult worm and soluble egg antigens (AWA and SEA), along with schistosomula recombinant proteins rSmKK7, Lymphocyte Antigen 6 isoforms (rSmLy6A and rSmLy6B), tetraspanin isoforms (rSmTSP6 and rSmTSP7). Cytokines, chemokines and growth factors were measured in the culture supernatants using a multiplex luminex assay, and infection intensity was determined before and at 1 year after praziquantel (PZQ) treatment using the Kato-Katz method. Cellular responses were grouped and the relationship between groups of correlated cellular responses and infection intensity before and after PZQ treatment was investigated. AWA and SEA induced mainly Th2 responses. In contrast, rSmLy6B, rSmTSP6 and rSmTSP7 induced Th1/pro-inflammatory responses. While recombinant antigens rSmKK7 and rSmLy6A did not induce a Th1/pro-inflammatory response, they had an association with pre-treatment infection intensity after adjusting for age and sex. Testing more schistosomula antigens using this approach could provide immune-epidemiology identifiers necessary for prioritizing next generation schistosomiasis vaccine candidates

Variation in <i>Schistosoma</i> antigen-induced cytokine responses in relation to <i>Schistosoma</i> infection status.

<p>Each three-dimensional (3D) nMDS ordination is represented in two 2D planes (<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd.0003080.s001" target="_blank">Supporting Information S1</a>) as in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd-0003080-g001" target="_blank">Figure 1</a>: Left and right panels represent the 1^st and 2^nd, and 2^nd and 3^rd dimensions, respectively. <b>Panels A</b> and <b>B</b> show the <i>S. mansoni</i> egg antigen (SEAm)-induced cytokine profile, <b>Panels C</b> and <b>D</b> that of <i>S. haematobium</i> SEA(h), <b>Panels E</b> and <b>F</b> that of <i>S. mansoni</i> adult worm antigens (AWAm), and <b>Panels G</b> and <b>H</b> show <i>S. haematobium</i> AWA(h)-induced cytokine profiles. Dots represent individuals and distances between dots approximate the rank order of dissimilarities in cytokine profiles between the respective individuals with stress values (i.e. discrepancies) of 0.051 for SEAm, 0.041 for SEAh, 0.058 for AWAm, and 0.061 for AWAh. Red arrows indicate linear gradients of normalized net cytokine responses on which the nMDS is based. The length of the arrows is proportional to the goodness of fit onto the cytokine profile within one 2D plane, and arrows are only depicted if their fit was significant at the level of <i>p</i> = 0.05 in 3D ordinations (see <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd-0003080-t004" target="_blank">Table 4</a>), as well as in the respective 2D planes. Green dots represent uninfected individuals, dark blue those with single <i>S. mansoni</i> infections, light blue single <i>S. haematobium</i>, and the other colors indicate people with mixed infections: pink indicates mixed infections without ectopic egg elimination, yellow mixed infections with <i>S. mansoni</i> in feces as well as in urine and <i>S. haematobium</i> in urine, and red dots represent one individual with both <i>S. mansoni</i> and <i>S. haematobium</i> eggs in urine (possibly a hybrid species <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd.0003080-Meurs1" target="_blank">[4]</a>–<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd.0003080-Huyse1" target="_blank">[6]</a>; see also <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd-0003080-t001" target="_blank">Table 1</a>). Ellipsoids represent 95% confidence intervals for average group scores, for different infection statuses: uninfected (‘N’), single <i>S. mansoni</i> (‘M’), single <i>S. haematobium</i> (‘H’), versus mixed infection (‘MH’). Ellipsoids are drawn using the function ‘ordiellipse’, and only depicted if the fit of infection status onto the cytokine profile was significant at the level of <i>p</i> = 0.05 in 3D ordinations (see <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd-0003080-t004" target="_blank">Table 4</a>), as well as in the respective 2D planes. In Panel A and G, the labels for single <i>S. mansoni</i> (‘M’) and mixed infection (‘MH’) are overlapping. ^aThe biological a posteriori interpretation of nMDS1 (left x-axis) and nMDS2 (y-axis) were added between brackets on the axis labels, but nMDS3 (right x-axis) could not be interpreted.</p

<i>Schistosoma</i> infections in the study population.

a<p><i>Schistosoma mansoni</i> eggs that were ectopically excreted in the urine had a <i>S. mansoni</i>-like morphology but may have had a genetically hybrid constitution <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd.0003080-Meurs1" target="_blank">[4]</a>, <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003080#pntd.0003080-Huyse1" target="_blank">[6]</a>.</p