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Egg Antigen (egg + antigen)

Distribution by Scientific Domains

Medical Sciences	87%

Selected Abstracts

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

FEBS JOURNAL, Issue 10 2006
Manfred Wuhrer
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. [source]

The immunobiology of Th1 polarization in high-pathology schistosomiasis

IMMUNOLOGICAL REVIEWS, Issue 1 2004
Miguel J. Stadecker
Summary:, Schistosomiasis is a serious global helminthic disease, in which the main immunopathology consists of a granulomatous and fibrosing reaction against tissue-trapped parasite eggs. The severity of this inflammatory process, the product of a CD4+ T-cell-mediated immune response against parasite egg antigens, is, however, markedly uneven, both in human patients and among mouse strains in an experimental model. Severe schistosomiasis is associated with persistently elevated pro-inflammatory T-helper-1 (Th1)-type cytokines, whereas milder pathology is present when Th2 cytokines dominate. This scenario is supported by the pronounced pathology resulting from the obliteration of pathways that facilitate Th2 differentiation and by the development of more intense lesions in mouse strains that fail to downregulate the Th1 response. Genetically prone high-pathology mice have a higher proportion of CD4+ T cells in lymph nodes and granulomas, in which the Th1 phenotype is driven by interleukin-12; they also develop a dominant repertoire against peptide 234,246 of the major Sm-p40 egg antigen, utilizing a strikingly restricted T-cell receptor structure that involves V,11.3,8. In turn, low-pathology mice exhibit enhanced CD4+ T-cell apoptosis, which contributes to limit pathology. The definition of distinctive immune profiles associated with polar forms of schistosomiasis opens opportunities for targeted immuno-intervention in individuals suffering from or at risk of severe disease. [source]

Apoptosis: a mechanism of immunoregulation during human schistosomiasis mansoni

PARASITE IMMUNOLOGY, Issue 6 2000
Patricia Carneiro-Santos
People infected with schistosomes may present with a variety of clinical manifestations ranging from the relatively asymptomatic intestinal (INT) form to the hepatointestinal (HI) or hepatosplenic (HS) forms characterized by hepatomegaly and hepatosplenomegaly with severe portal hypertension, respectively. Flow cytometry analyses were used to evaluate the contribution of apoptosis in specific cell populations from schistosomiasis patients to the development of the different clinical forms of the disease. The results showed that cell death induced by combinations of specific antigen and cytokines corresponds with specific clinical presentations. It was shown that soluble egg antigen (SEA) increased the level of apoptosis only in T cells from INT patients. Stimulation with soluble lung worm antigen preparation (SLAP) did not induce significant differences in the levels of apoptosis in T cells from the patients with the different clinical forms of schistosomiasis. These results suggest for the first time that apoptosis plays an important role in the modulation of the anti-SEA response in INT patients. [source]

Age- and sex-related differences in antibody responses against Schistosoma mansoni soluble egg antigen in a cohort of school children in Ethiopia,

APMIS, Issue 12 2001
F. ABEBE
Acquired immunity is believed to be the main factor in the age-related differences in prevalence and intensity of Schistosoma infections. We studied antibody responses against S. mansoni soluble egg antigen (SEA) by ELISA in children before treatment, 5 weeks and one year after treatment. After screening for S. mansoni infection, positive children were treated with praziquantel (40 mg per kg body weight). Infection rate was significantly higher in boys younger than 12 years than in girls in the same age group. Levels of all antibody isotypes, except IgG1 (before treatment) or IgA (one year after treatment), were higher in children older or equal to 12 years than in those younger. The difference between age groups was significant for IgE, IgM, IgG3 and IgG4 (before treatment) and IgE (one year after treatment). Similarly, all antibody isotypes, except IgE, before treatment were higher in boys than in girls. At 5 weeks after treatment, IgG, IgE and IgG1 showed an increasing tendency, whereas IgM and IgG3 tended to decrease. One year after treatment, significant decreases were observed in IgG, IgG1 and IgG4 and a significant increase in IgG2 levels. The study presents further evidence for the difference in acquired immunity between younger and older children, and between boys and girls. The study also suggests that praziquantel differentially affects antibody responses against S. mansoni SEA. [source]

The immunobiology of Th1 polarization in high-pathology schistosomiasis

Chemokine responses in schistosomal antigen-elicited granuloma formation,

PARASITE IMMUNOLOGY, Issue 6 2002
Bo-Chin Chiu
Summary Host immune systems have evolved specialized responses to multicellular parasites. This is well represented by the type 2 granulomatous response to Schistosoma mansoni egg antigens, which is an eosinophil-rich inflammatory response mediated by Th2-associated cytokines. Using Ag-bead models of pulmonary granuloma formation in mice, we defined characteristic chemokine (CK) profiles in the granulomatous lungs. Our findings point to a role for C-C chemokine receptor-2 (CCR2) and CCR3 agonists such as monocyte chemotactic proteins (MCPs) 1/CCL2, 3/CCL7 and 5/CCL12 as important participants that are subject to regulation by Th2 cytokines interleukin (IL)-4 and IL-13. CCR4 and CCR8 agonists are also likely contributors. Analysis of CK receptor knockout mice revealed that CCR2 ligands (e.g. MCP-1 and 5) promoted early phase granuloma macrophage accumulation, whereas anti-MCP-3 (CCL7) antibody treatment abrogated eosinophil recruitment. CCR8 knockout mice also demonstrated impaired eosinophil recruitment but this appeared to be related to impaired Th2 cell function. Transcript analysis of CD4+ T cells generated during schistosome granuloma formation failed to show biased CCR8 expression but, having a more limited receptor repertoire, these cells were likely more dependent on CCR8 ligands. Together, these studies indicate an intricate involvement of chemokines in various stages and aspects of schistosomal egg Ag-elicited granuloma formation. [source]

Cytokine responses to mitogen and Schistosoma haematobium antigens are different in children with distinct infection histories

PARASITE IMMUNOLOGY, Issue 10 2001
Janet T. Scott
Prevalence of Schistosoma haematobium infection in children from two neighbouring villages in Zimbabwe was 77·1% and 40·3%, respectively. The age-intensity data indicated peak intensities of infection at a lower age in the high prevalence village. This study investigated whether the difference in infection histories was reflected in a difference in cytokine profiles between children resident in these two villages. Blood samples were taken to assay for cytokine secretion 1 year after treatment for schistosomiasis. They were cultured with phytohaemagglutinin (PHA), schistosome egg antigens (SEA) or cultured without stimulant and tested for the presence of interleukin (IL)-4, IL-5, IL-10, granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-,. Blood samples from children from the low prevalence village were more likely to produce IL-4 (P < 0·0001) and produced higher levels of IFN-, (P < 0·02) and GM-CSF (P < 0·03) when cultured with PHA for 24 h. Residence in the high prevalence village was associated with production of IL-10 (P < 0·006) and GM-CSF (P < 0·04) in response to culture with SEA and IL-5 (P < 0·02) with PHA for 48 h. The interaction between age and village was not significant for these results; however, there was a significant interaction between age and village for IL-5 detected in blood samples cultured with PHA for 24 h (P < 0·01). These results concur with previous observations that major patterns of cytokine production can be related to immunosuppression, but also indicate an underlying pattern which reflects the importance of history of infection to the immune response. [source]