Frances M. Jones

Schistosoma mansoni antigens modulate the activity of the innate immune response and prevent onset of type 1 diabetes

Infection with Schistosoma mansoni (S. mansoni) or exposure to eggs from this helminth inhibits the development of type 1 diabetes in NOD mice. In this study we show that soluble extracts of S. mansoni worm or egg completely prevent onset of type 1 diabetes in these mice but only if injection is started at 4 weeks of age. T cells from diabetes‐protected mice make IL‐10 in recall responses to parasite antigens. These cells are furthermore impaired in their ability to transfer diabetes to NOD‐SCID recipients. Bone marrow dendritic cells derived from NOD mice are found to make more IL‐10 and less IL‐12 following culture with S. mansoni soluble egg antigens in conjunction with lipopolysaccharides. NOD mice are deficient in NKT cells. Soluble worm and egg antigens increase the numbers of Vα14i NKT cells in NOD mice. These effects of schistosome antigens on the innate immune system provide a mechanism for their ability to prevent type 1 diabetes in NOD mice.

Periportal fibrosis in human Schistosoma mansoni infection is associated with low IL-10, low IFN-gamma, high TNF-alpha, or low RANTES, depending on age and gender.

Schistosoma mansoni infection is highly endemic in parts of Uganda, and periportal fibrosis is common in communities along the shore of Lake Albert. In this study, we have identified cellular immune responses associated with fibrosis. A cohort of 199 individuals aged 6–50, resident in the village for at least 10 years or since birth, were examined for evidence of periportal fibrosis by ultrasound using the Niamey protocol. Whole-blood samples were assayed for levels of nine cellular immune molecules (IL-3, IL-4, IL-5, IL-10, IL-13, TNF-α, IFN-γ, IL-1β, and RANTES) in the absence of in vitro Ag stimulation, and after stimulation with egg and worm Ags. A lack of Ag specificity allowed the number of variables in the analysis to be reduced by factor analysis. The resulting factor scores were then entered into a risk analysis using a classification tree algorithm. Children, adult males, and adult females had different factors associated with fibrosis. Most cases of fibrosis in children (eight of nine) were associated with low (<47th percentile) IL-10 factor scores. Adult females at lowest risk had relatively high IFN-γ factor scores (>83rd percentile), whereas those at highest risk had a combination of intermediate (32nd to 83rd percentile) IFN-γ and relatively high (>60th percentile) TNF-α factor scores. Adult males at lowest risk of fibrosis had moderate TNF-α factor scores (55th to 82nd percentile), and a high risk was associated with either high TNF-α factor scores (>82nd percentile), or intermediate TNF-α combined with low RANTES factor scores (<58th percentile). These results demonstrate that periportal fibrosis is associated with cytokine production profiles that vary with both age and gender.

Schistosoma mansoni egg antigens induce Treg that participate in diabetes prevention in NOD mice.

Schistosoma mansoni soluble egg antigens (SEA) profoundly regulate the infected hosts immune system. We previously showed that SEA prevents type 1 diabetes in NOD mice and that splenocytes from SEA‐treated mice have reduced ability to transfer diabetes to NOD.scid recipients. To further characterize the mechanism of diabetes prevention we examined the cell types involved and showed that CD25+ T‐cell depletion of splenocytes from SEA‐treated donors restored their ability to transfer diabetes. Furthermore, SEA treatment increased the number and proportional representation of Foxp3+ T cells in the pancreas of NOD mice. We have used in vitro systems to analyze the effect of SEA on the development of NOD Foxp3+ T cells. We find that SEA can induce Foxp3 expression in naïve T cells in a TGF‐β‐dependent manner. Foxp3 induction requires the presence of DC, which we also show are modified by SEA to upregulate C‐type lectins, IL‐10 and IL‐2. Our studies show that SEA can have a direct effect on CD4+ T cells increasing expression of TGF‐β, integrin β8 and galectins. These effects of SEA on DC and T cells may act in synergy to induce Foxp3+ Treg in the NOD mouse.

Pulmonary Vascular Remodeling Correlates with Lung Eggs and Cytokines in Murine Schistosomiasis

RATIONALE Schistosomiasis is considered to be the most common worldwide cause of pulmonary hypertension. At present there is no well-characterized animal model to study the pathobiology of this important condition. OBJECTIVES To develop a mouse model of schistosomiasis, characterize the extent of pulmonary vascular remodeling, and determine the potential role of inflammatory cytokines. METHODS Mice (C57/Bl6) were infected transcutaneously with a high dose (approximately 75-100 cercariae) or a low dose (approximately 30 cercariae) of Schistosoma mansoni, and the development of lung and liver pathology was studied in the subacute (high-dose) and chronic (low-dose) settings. MEASUREMENTS AND MAIN RESULTS In the subacute setting, mice showed few eggs in the lungs and no evidence of pulmonary vascular remodeling. In contrast, chronically infected animals had a much greater lung egg burden and developed marked pulmonary vascular remodeling accompanied by perivascular inflammation from 12 weeks onwards. In addition, we observed the presence of plexiform-like lesions in these mice. Lung egg burden correlated with both liver egg burden and right ventricular (RV) index in the chronic group, although significant RV hypertrophy was lacking. Plasma Th1 and Th2 cytokines increased with time in the chronic group and correlated with the degree of pulmonary vascular remodeling. CONCLUSIONS This study provides evidence for extensive pulmonary vascular remodeling, despite the absence of RV hypertrophy, in a mouse model of schistosomiasis, including the formation of plexiform-like lesions. Inflammatory cytokines and lung egg burden may contribute to vascular lesion formation.

Anthelminthic treatment during pregnancy is associated with increased risk of infantile eczema: randomised-controlled trial results

To cite this article: Mpairwe H, Webb EL, Muhangi L, Ndibazza J, Akishule D, Nampijja M, Ngom‐wegi S, Tumusime J, Jones FM, Fitzsimmons C, Dunne DW, Muwanga M, Rodrigues LC, Elliott AM. Anthelminthic treatment during pregnancy is associated with increased risk of infantile eczema: randomised‐controlled trial results. Pediatr Allergy Immunol 2011; 22: 305–312.

Increases in human T helper 2 cytokine responses to Schistosoma mansoni worm and worm-tegument antigens are induced by treatment with praziquantel.

Levels of Schistosoma mansoni-induced interleukin (IL)-4 and IL-5 and posttreatment levels of immunoglobulin E recognizing the parasites tegument (Teg) correlate with human resistance to subsequent reinfection after treatment. We measured changes in whole-blood cytokine production in response to soluble egg antigen (SEA), soluble worm antigen (SWA), or Teg after treatment with praziquantel (PZQ) in a cohort of 187 individuals living near Lake Albert, Uganda. Levels of SWA-induced IL-4, IL-5, IL-10, and IL-13 increased after treatment with PZQ, and the greatest relative increases were seen in the responses to Teg. Mean levels of Teg-specific IL-5 and IL-10 increased ~10-15-fold, and mean levels of IL-13 increased ~5-fold. Correlations between the changes in cytokines suggested that their production was positively coregulated by tegumentally derived antigens. Levels of SEA-, SWA-, and Teg-induced interferon- gamma were not significantly changed by treatment, and, with the exception of IL-10, which increased slightly, responses to SEA also remained largely unchanged. The changes in cytokines were not strongly influenced by age or intensity of infection and were not accompanied by corresponding increases in the numbers of circulating eosinophils or lymphocytes.

The purification, characterization, serological activity and hepatotoxic properties of two cationic glycoproteins (α 1 and ω 1 ) from Schistosoma mansoni eggs

T cell-deprived mice acutely infected with S. mansoni suffer microvesicular hepatocyte damage which is not seen in infected, immunological intact animals. A cationic fraction (CEF6) of the PBS-soluble portion of S. mansoni eggs (SEA) induces antibodies which, on passive transfer, prevent hepatocyte damage. CEF6 contains 2 antigens, omega 1 and alpha 1, and has also been shown to be a useful serodiagnostic reagent. This paper describes the purification and characterization of the 2 antigens present in CEF6. omega 1 is a monomeric glycoprotein with a pI greater than 9.0 and a molecular weight of 31 kDa. Alpha 1 consists of two immunologically cross-reactive dimers, 41 and 36 kDa in non-reducing conditions, each of which consists of one unique and one common glycoprotein subcomponent. In ELISA with mouse and human infection sera omega 1 is shown to be S. mansoni specific and is better able to distinguish S. mansoni infections from other schistosome infections than are unfractionated SEA, CEF6 or alpha 1. Passive transfer of monospecific anti-omega 1 sera into S. mansoni infected, T cell-deprived mice completely prevented the occurrence of microvesicular hepatocyte damage in these animals. Monospecific anti-alpha 1 serum had no hepatoprotective capacity.

Parasite-Derived MicroRNAs in Host Serum As Novel Biomarkers of Helminth Infection

Background MicroRNAs (miRNAs) are a class of short non-coding RNA that play important roles in disease processes in animals and are present in a highly stable cell-free form in body fluids. Here, we examine the capacity of host and parasite miRNAs to serve as tissue or serum biomarkers of Schistosoma mansoni infection. Methods/Principal Findings We used Exiqon miRNA microarrays to profile miRNA expression in the livers of mice infected with S. mansoni at 7 weeks post-infection. Thirty-three mouse miRNAs were differentially expressed in infected compared to naïve mice (>2 fold change, p<0.05) including miR-199a-3p, miR-199a-5p, miR-214 and miR-21, which have previously been associated with liver fibrosis in other settings. Five of the mouse miRNAs were also significantly elevated in serum by twelve weeks post-infection. Sequencing of small RNAs from serum confirmed the presence of these miRNAs and further revealed eleven parasite-derived miRNAs that were detectable by eight weeks post infection. Analysis of host and parasite miRNA abundance by qRT-PCR was extended to serum of patients from low and high infection sites in Zimbabwe and Uganda. The host-derived miRNAs failed to distinguish uninfected from infected individuals. However, analysis of three of the parasite-derived miRNAs (miR-277, miR-3479-3p and bantam) could detect infected individuals from low and high infection intensity sites with specificity/sensitivity values of 89%/80% and 80%/90%, respectively. Conclusions This work identifies parasite-derived miRNAs as novel markers of S. mansoni infection in both mice and humans, with the potential to be used with existing techniques to improve S. mansoni diagnosis. In contrast, although host miRNAs are differentially expressed in the liver during infection their abundance levels in serum are variable in human patients and may be useful in cases of extreme pathology but likely hold limited value for detecting prevalence of infection.

Immune Modulation by Schistosoma mansoni Antigens in NOD Mice: Effects on Both Innate and Adaptive Immune Systems

We have shown that Schistosoma mansoni egg soluble antigen (SEA) prevents diabetes in the nonobese diabetic (NOD) mouse inducing functional changes in antigen presenting cells (APCs) and expanding T helper (Th) 2 and regulatory T cell (Treg) responses. A Th2 response to S. mansoni infection or its antigens is key to both the establishment of tolerance and successfully reproduction in the host. More recently we demonstrated that SEA treatment upregulates bioactive TGFβ on T cells with consequent expansion of Foxp3+ Tregs, and these cells might be important in SEA-mediated diabetes prevention together with Th2 cells. In this study we profile further the phenotypic changes that SEA induces on APCs, with particular attention to cytokine expression and markers of macrophage alternative activation. Our studies suggest that TGFβ from T cells is important not just for Treg expansion but also for the successful Th2 response to SEA, and therefore, for diabetes prevention in the NOD mouse.

IPSE/alpha-1, a major secretory glycoprotein antigen from schistosome eggs, expresses the Lewis X motif on core-difucosylated N-glycans

Schistosomes are parasitic flatworms that infect millions of people in (sub)tropical areas around the world. Glycoconjugates of schistosomes play a critical role in the interaction of the different developmental stages of the parasite with the host. In particular, glycosylated components of the eggs produced by the adult worm pairs living in the bloodstream are strongly immunogenic. We have investigated the glycosylation of interleukin‐4‐inducing factor from schistosome eggs (IPSE/alpha‐1), a major secretory egg antigen from Schistosoma mansoni that triggers interleukin‐4 production in human basophils, by MS analysis of tryptic glycopeptides. Nanoscale LC‐MS(/MS) and MALDI‐TOF(/TOF)‐MS studies combined with enzymatic degradations showed that monomeric IPSE/alpha‐1 contains two N‐glycosylation sites, which are each occupied for a large proportion with core‐difucosylated diantennary glycans that carry one or more Lewis X motifs. Lewis X has been reported as a major immunogenic glycan element of schistosomes. This is the first report both on the expression of Lewis X on a specific schistosome egg protein and on a protein‐specific glycosylation analysis of schistosome eggs.