Schistosoma Mansoni Egg Antigen Research Articles

Praziquantel pharmacotherapy reduces systemic osteopontin levels and liver collagen content in murine schistosomiasis mansoni

The pathogenesis of schistosomiasis and the mechanism of disease regression after Praziquantel pharmacotherapy are not fully elucidated. Schistosoma mansoni egg antigens directly stimulate the expression of the profibrogenic molecule osteopontin (OPN), and systemic OPN levels strongly correlate with disease severity, suggesting its use as a potential morbidity biomarker. In this study, we investigated the impact of Praziquantel use on systemic OPN levels and on liver collagen deposition in chronic murine schistosomiasis. Praziquantel treatment significantly reduced systemic OPN levels and liver collagen deposition, indicating that OPN could be a reliable tool for monitoring PZQ efficacy and fibrosis regression in murine schistosomiasis.

Antigenic cross-reactivity between Schistosoma mansoni and allergenic invertebrates putatively due to shared glycanic epitopes

Previous studies have shown that rabbit IgG antibodies against Schistosoma mansoni egg antigens (SmSEA) cross-react with allergens in natural rubber latex, peanuts and grass and tree pollens. Here we describe antigenic molecules that cross-react with rabbit anti-S. mansoni IgG antibodies in extracts of the house dust mite (HDM) Dermatophagoides farinae, the Australian cockroach (ACR) Periplaneta australasiae and in the venom of the honey bee Apis mellifera (HBV). Tandem mass spectrometry identified the cross-reactive allergens as Der f 15 in HDM, two homologues of the Periplaneta americana cockroach allergen Cr-PI/Per a 3 in ACR and two isoforms of the allergen Api m 1 (phospholipase A2: PLA2) in HBV. Cross-reactive rabbit anti-SmSEA IgG antibodies eluted from the three invertebrate allergens reacted with S. mansoni egg antigens and variably with schistosome cercarial and worm antigens. Treatment of the electroblotted allergens with sodium metaperiodate abrogated most of the cross-reactivity of the rabbit anti-SmSEA antibodies, suggesting it was due to cross-reactive carbohydrate determinants (CCDs). Furthermore, analyses of the allergens’ amino acid sequences indicated that they had potential for both N- and O-linked glycosylation. A potential role for the CCDs shared by the schistosome and invertebrates in inducing an allergy-protective effect, as proposed by the hygiene hypothesis, is discussed.

The self-curing phenomenon of schistosome infection in rhesus macaques: insight from in vitro studies.

A reduction in the burden of schistosomiasis is potentially achievable by integrating a schistosomiasis vaccine with current control measures. Here, we determine parasite-specific in vitro responses of B, T, and NK cells from naive uninfected rhesus macaques to Schistosoma mansoni (Sm) egg (SmEA) and worm antigen (SmWA) preparations isolated from infected baboons. Pronounced B cell responses to SmEA and NK cell responses to both SmEA and SmWA were observed. High levels of IL-2 and IL-21 responses against Sm antigens were observed in T and non-T cells of lymph nodes (LNs) and gut lamina propria-derived lymphocytes (LPLs). Data analysis showed multifunctionality of LN-derived CD4+ , CD8+ , and CD4+ CD8+ double positive T cells against either SmWA or SmWA+SmEA antigen preparations. Distinct SmEA-specific multifunctional responses were observed in gut LPLs, suggesting simultaneous responses against egg antigens. These data provide insight into the immune effectors involved in schistosome responses by rhesus macaques.

Efficacy of L-carnosine against Schistosoma mansoni antigens in liver, heart, kidney and brain of rabbits

Article history: The present investigation was an attempt to study the enhancememt effect of L-carnosine (beta alanyl-l-histidine) on the influence of vaccination on healthy (non-infected) rabbits treated with Schistosoma mansoni egg antigens, cercariae antigens, and worms antigens as protective agents against infection. This study involved individual injection of three Schistosoma mansoni antigens: soluble egg antigen (SEA), cercarial antigen preparation (CAP) and soluble worm antigen preparation (SWAP), in three rabbit groups, respectively. Three other groups each received the same specific antigen in conjunction with the administration of L-carnosine, biochemical parameters including DNA, RNA, DNA/RNA ratio concentrations in addition ATPase, and acetyl cholinesterase activities were measured in liver, heart, kidney and brain in all groups. Elevation in most parameters was observed in the immunized groups. Carnosine treatment of rabbit groups immunized with SEA, CAP and SWAP in comparison to the non-carnosine-treated immunized groups resulted in amelioration the changes of DNA, RNA, ATPase and acetyl cholinesterase activities in most groups. L-carnosine has a beneficial effect in the amelioration of the changes in biochemical parameters as a result of S. mansoni antigen immunization.

Evaluation of the immunological effect of beta alanyl-l-histidine against Schistosoma mansoni antigens in rabbits

The influence of vaccination on healthy (non-infected) rabbits treated with Schistosoma mansoni egg antigens, cercariae, and worms as prophylactic agents against infection, and the benefit of beta alanyl-l-histidine treatment against Schistosoma mansoni infection were investigated. This study involved individual injection of three Schistosoma mansoni antigens: soluble egg antigen (SEA), cercarial antigen preparation (CAP) and soluble worm antigen preparation (SWAP), in three rabbit groups, respectively. Three other groups each received the same specific antigen in conjunction with the administration of (beta alanyl-l-histidine) L-carnosine. Hepatic total protein, glycogen and glycogen phosphorylase, total serum protein and one diminution electrophoresis of protein fractions (180 KDa; 116 KDa; 97, 4 KDa, serum albumin 66 KDa; 48. 5 KDa; 29 KDa; 18.400 KDa; 14.200 KDa; 6.5 KDa) were measured in all the rabbit groups. Elevation in most parameters was observed in the immunized groups. Carnosine treatment of rabbit groups immunized with SEA, CAP and SWAP in comparison to the non-carnosine-treated immunized groups resulted in amelioration of serum protein fractions in all SEA and SWAP-immunized animals, and reduction in glycogen phosphorylase b in SWAP animals alone. In addition, changes in glycogen content were observed in the CAP-immunized group. L-carnosine has a beneficial effect in the amelioration of most biochemical parameters as a result of S. mansoni antigen immunization.

Dysregulated Cytokine Expression by CD4+ T cells from Post-Septic Mice Modulates both Th1 and Th2-Mediated Granulomatous Lung Inflammation

Previous epidemiological studies in humans and experimental studies in animals indicate that survivors of severe sepsis exhibit deficiencies in the activation and effector function of immune cells. In particular, CD4+ T lymphocytes can exhibit reduced proliferative capacity and improper cytokine responses following sepsis. To further investigate the cell-intrinsic defects of CD4+ T cells following sepsis, splenic CD4+ T cells from sham surgery and post-septic mice were transferred into lymphopenic mice. These recipient mice were then subjected to both TH1-(purified protein derivative) and TH2-(Schistosoma mansoni egg antigen) driven models of granulomatous lung inflammation. Post-septic CD4+ T cells mediated smaller TH1 and larger TH2 lung granulomas as compared to mice receiving CD4+ T cells from sham surgery donors. However, cytokine production by lymph node cells in antigen restimulation assays indicated increased pan-specific cytokine expression by post-septic CD4+ T cell recipient mice in both TH1 and TH2 granuloma models. These include increased production of TH2 cytokines in TH1 inflammation, and increased production of TH1 cytokines in TH2 inflammation. These results suggest that cell-intrinsic defects in CD4+ T cell effector function can have deleterious effects on inflammatory processes post-sepsis, due to a defect in the proper regulation of TH-specific cytokine expression.

The role of chemokines in controlling granulomatous inflammation in Schistosoma mansoni infection

Chemokines are a superfamily of low-molecular-weight cytokines that were initially described for their chemoattractant activity. It is now clear chemokines have several other activities that modulate immune processes. Chemokines appear to play a role in the pathogenesis of several inflammatory diseases. The role of chemokines and their receptors in mediating granulomatous inflammation induced by Schistosoma mansoni egg antigens presented in particulate manner have been studied in detail. Much less is known of the role of chemokines in mediating inflammation during the course of S. mansoni infection. Our studies in mice suggest a relevant role for the chemokine CCL3 and the receptor CCR5 in the pathogenesis of experimental S. mansoni infection. Absence of CCL3 is associated with decrease in granuloma size, fibrosis and parasite load. In humans, levels of CCL3 in plasma associate with disease severity and may be useful for diagnostic purposes. In contrast, absence of CCR5 is associated with enhanced lethality, granuloma size and fibrosis. It is suggested that the balance of chemokine production and chemokine receptor activation are important determinants of the fate of infection in experimental animals and humans.

STAT1 is Involved in the Pathogenesis of Murine Allergic Rhinitis

Signal transducer and activator of transcription (STAT) 1 signaling pathway mediates biological functions of interferon (IFN) gamma, which is a key cytokine-regulating T helper 1 (Thl) differentiation. Although constitutive activation of STAT1 has been reported in the airway epithelium of patients with chronic asthma, its in vivo role in the pathogenesis of allergic rhinitis is not clear. We determined the role of STAT1 in the pathogenesis of allergic rhinitis in vivo using STAT1 gene-deficient (STAT1-/-) mice and a murine model of Schistosoma mansoni egg antigen (SEA)-induced allergic rhinitis. STATI -/- BALB/c and wild-type (WT) mice were sensitized by intranasal administration of SEA, and their immunologic responses were examined. STATI-1- mice showed impaired nasal eosinophilia and markedly reduced histamine-induced nasal hyperresponsiveness after SEA sensitization. Moreover, levels of Th2-associated SEA-specific IgG1 and IgE antibodies were lower in STAT1-/- mice. Anti-CD3stimulated nasal lymphocytes from STAT1-/-mice also produced less amounts of Th2-associated cytokines IL-4, IL-5, IL-10, and IL-13 compared with WT mice, but both produced comparable levels of IFN-gamma. These results show that STAT1 is involved in the pathogenesis of SEA-induced allergic rhinitis in BALB/c mice. Furthermore, they reveal a surprising role of STAT1 in induction of nasal eosinophilia, and Th2-type cytokine production from nasal lymphocytes during allergic rhinitis.

Signals through CD40 Play a Critical Role in the Pathophysiology of Schistosoma Mansoni Egg Antigen–Induced Allergic Rhinitis in Mice

Interaction between CD40 and CD40L is thought to regulate immune responses in several allergic diseases. However, little is known about its in vivo role in the pathophysiology of allergic rhinitis. We sought to determine whether the lack of signals through CD40 affects the pathophysiology of allergic rhinitis using a murine model. Wild type (WT) and CD40-deficient BALB/c (CD40-/-) mice were sensitized intranasally to Schistosoma mansoni egg antigen (SEA). After repeated sensitization, histamine responsiveness, serum antibody titer including immunoglobulin E (IgE), nasal eosinophilia, and cytokine production by nasal mononuclear cells were determined in each group. Intranasal sensitization with SEA in WT mice elicited a strong Th2 response including SEA-specific IgE production, nasal eosinophilia, and interleukin (IL)-4, and IL-5 production by nasal mononuclear cells after antigen challenge. Production of SEA-specific IgE and IgG1 was abolished in SEA-sensitized CD40-/- mice. These mice showed impaired nasal eosinophilia and displayed markedly reduced histamine-induced nasal hyperresponsiveness as compared with WT mice. Furthermore, reduced production of IL-4 and IL-5 by nasal mononuclear cells was seen in CD40-/- mice. These results show that signals through CD40 play a critical role in not only IgE production but also pathophysiology of allergic rhinitis such as nasal hyperresponsiveness and nasal eosinophilia.

Nasal exposure to Staphylococcal enterotoxin enhances the development of allergic rhinitis in mice

Staphylococcal enterotoxins (SEs) appear to play a role in the pathogenesis of allergic disease. However, little is known whether the nasal exposure to SE affects the development of allergic rhinitis (AR). We sought to determine the in vivo effect of nasal exposure to SE on the development of AR using mouse model. BALB/c mice were intranasally sensitized with Schistosoma mansoni egg antigen (SmEA) in the presence or absence of staphylococcal enterotoxin B (SEB). Control mice were intranasally sensitized with either SEB or SmEA alone. The production of antigen-specific antibodies including IgE, nasal eosinoplilia and cytokines by nasal mononuclear cells was compared among mice that had or had not received SEB treatment. Nasal exposure to SEB enhanced the development of AR in SmEA-sensitized mice, as manifested by SmEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal mononuclear cells after Ag challenge. This treatment also elicited IFN-gamma production by SmEA-primed cells. In addition, these mice produced SEB-specific IgE whereas mice treated with SEB without SmEA sensitization did not produce SEB-specific IgE or demonstrate nasal eosinophilia. These results suggest that the nasal exposure to SEB enhances susceptibility to AR although the exposure to SE solely does not induce AR.

Molecular Basis of the Differences in Binding Properties of the Highly Related C-type Lectins DC-SIGN and L-SIGN to Lewis X Trisaccharide and Schistosoma mansoni Egg Antigens

The dendritic cell-specific C-type lectin DC-SIGN functions as a pathogen receptor that recognizes Schistosoma mansoni egg antigens through its major glycan epitope Galbeta1,4(Fucalpha1,3)GlcNAc (Lex). Here we report that L-SIGN, a highly related homologue of DC-SIGN found on liver sinusoidal endothelial cells, binds to S. mansoni egg antigens but not to the Lex epitope. L-SIGN does bind the Lewis antigens Lea, Leb, and Ley, similar as DC-SIGN. A specific mutation in the carbohydrate recognition domain of DC-SIGN (V351G) abrogates binding to all Lewis antigens. In L-SIGN Ser363 is present at the corresponding position of Val351 in DC-SIGN. Replacement of this Ser into Val resulted in a "gain of function" L-SIGN mutant that binds to Lex, and shows increased binding to the other Lewis antigens. These data indicate that Val351 is important for the fucose specificity of DC-SIGN. Molecular modeling and docking of the different Lewis antigens in the carbohydrate recognition domains of L-SIGN, DC-SIGN, and their mutant forms, demonstrate that Val351 in DC-SIGN creates a hydrophobic pocket that strongly interacts with the Fucalpha1,3/4-GlcNAc moiety of the Lewis antigens. The equivalent amino acid residue Ser363 in L-SIGN creates a hydrophilic pocket that prevents interaction with Fucalpha1,3-GlcNAc in Lex but supports interactions with the Fucalpha1,4-GlcNAc moiety in Lea and Leb antigens. These data demonstrate for the first time that DC-SIGN and L-SIGN differ in their carbohydrate binding profiles and will contribute to our understanding of the functional roles of these C-type lectin receptors, both in recognition of pathogen and self-glycan antigens.

Both free-living and parasitic nematodes induce a characteristic Th2 response that is dependent on the presence of intact glycans.

Infection with parasitic nematodes is characterized by the induction of a profound type 2 immune response. We have studied the role of glycans in the induction of the skewed type 2 response by antigens of the parasitic nematode Brugia malayi as well as the free-living nematode Caenorhabditis elegans. Lymph node cells from BALB/c mice immunized with soluble extracts of the two nematodes showed distinct antigen-specific proliferation and cytokine production; however, both nematodes induced antigen-specific interleukin 4 (IL-4) production, demonstrating that the induction of a biased type 2 response is not unique to parasitic nematodes. Sodium periodate-treated soluble extracts of both nematodes consistently induced significantly less IL-4 production than the respective mock-treated extracts, indicating that glycans play a critical role in the induction of the Th2 immune response by these nematodes. The glycan-dependent induction of the Th2-potentiating cytokine IL-4 occurs by 72 h postinoculation. Our data suggest that glycan determinants common to nematodes act as ligands, displaying distinct molecular patterns that trigger the immune system to launch a biased Th2 immune response upon exposure to these organisms or their products. Further, the similarity of our findings to those for Schistosoma mansoni egg antigen is striking considering the enormous phylogenetic distance between nematodes and trematodes. These data thus have important implications for how the mammalian host responds to widely divergent metazoan invaders and suggest that the powerful C. elegans model system can be used to address these questions.

The dendritic cell-specific C-type lectin DC-SIGN is a receptor for Schistosoma mansoni egg antigens and recognizes the glycan antigen Lewis x.

Schistosoma mansoni soluble egg antigens (SEAs) are crucially involved in modulating the host immune response to infection by S. mansoni. We report that human dendritic cells bind SEAs through the C-type lectin dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN). Monoclonal antibodies against the carbohydrate antigens Lewisx (Lex) and GalNAcbeta1-4(Fucalpha1-3)GlcNAc (LDNF) inhibit binding of DC-SIGN to SEAs, suggesting that these glycan antigens may be critically involved in binding. In a solid-phase adhesion assay, DC-SIGN-Fc binds polyvalent neoglycoconjugates that contain the Lex antigen, whereas no binding was observed to Galbeta1-4GlcNAc, and binding to neoglycoconjugates containing only alpha-fucose or oligosaccharides with a terminal alpha1-2-linked fucose is low. These data indicate that binding of DC-SIGN to Lex antigen is fucose-dependent and that adjacent monosaccharides and/or the anomeric linkage of the fucose are important for binding activity. Previous studies have shown that DC-SIGN binds HIV gp120 that contains high-mannose-type N-glycans. Site-directed mutagenesis within the carbohydrate recognition domain (CRD) of DC-SIGN demonstrates that amino acids E324 and E347 are involved in binding to HIV gp120, Lex, and SEAs. By contrast, mutation of amino acid Val351 abrogates binding to SEAs and Lex but not HIV gp120. These data suggest that DC-SIGN recognizes these ligands through different (but overlapping) regions within its CRD. Our data imply that DC-SIGN not only is a pathogen receptor for HIV gp120 but may also function in pathogen recognition by interaction with the carbohydrate antigens Lex and possibly LDNF, which are found on important human pathogens, such as schistosomes and the bacterium Helicobacter pylori.

Differential effects of ageing on cytokine and chemokine responses during type-1 (Mycobacterial) and type-2 (Schistosomal) pulmonary granulomatous inflammation in mice

Cytokine and chemokine responses during anamnestic type-1 and type-2 lung granuloma formation were evaluated in mice at 6, 12, 18 and 24-months of age. Lesions were induced by embolizing Sepharose beads coupled to Mycobacterium bovis purified protein derivative or soluble Schistosoma mansoni egg antigens. Type-1 inflammation was reduced by 18 months, whereas type-2 granulomas not until 24 months of age. In type-1 draining lymph nodes cultures, interferon-γ (IFNγ) declined to a nadir by 18, and then partly recovered at 24 months. In contrast, IL-4 was not significantly impaired in type-2 cultures until 24 months. Type-1 and 2 node cultures also displayed decreased IL-13, but paradoxically enhanced IL-5 production at 24 months. Chemokine transcripts in granulomatous lungs displayed age-related alterations. In the type-1 response, CXCL9 (monokine-induced by IFNγ) declined with age then partly recovered at 24 months parallelling lymph node IFNγ levels. Transcripts for MIP-2/CXCL2, IP-10/CXCL10, MCP-1/CCL2, and MCP-5/CCL12 increased at 24 months. In the type-2 response MCP-1/CCL2, MCP-3/CCL7, MCP-5/CCL12 and TARC/CCL17 collapsed at 24 months paralleling local IL-4 transcript levels, yet some chemokine transcripts such as KC/CXCL1 and eotaxin/CCL11 were unaffected. These findings suggest that cytokine and chemokine responses degrade differentially with age shifting Th1/Th2 crossregulatory pressures and local expression of chemokines.

Differential role of CD80 and CD86 molecules in the induction and the effector phases of allergic rhinitis in mice.

Selective involvement of CD80 and/or CD86 in the differentiation of T-helper (Th)1 and Th2 was seen in several diseases. In this study, we sought to determine the differential roles of CD80 and CD86 in the induction and effector phase of allergic rhinitis using Schistosoma mansoni egg antigen (SEA) as a specific Ag. Intranasal sensitization with SEA in BALB/c mice elicited a strong Th2 response including SEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal lymphocytes after Ag challenge. Blockade of CD80 at the induction phase significantly inhibited these manifestations, whereas no effect was observed by CD86 blockade. In contrast, the simultaneous blockade of both CD80 and CD86 during the effector phase partially inhibited IgE and IgG(1) production and nasal eosinophilia, although either blockade of CD80 or CD86 during the phase failed to inhibit these responses. Flow cytometric analysis on nasal mononuclear cells showed that CD80 but not CD86 was preferentially expressed on non-B cells by in vitro SEA stimulation in unsensitized mice. However, both CD80 and CD86 expression were significantly augmented by in vitro SEA stimulation in sensitized mice. Our results suggest the differential roles and expression of CD80 and CD86 in the development of allergic rhinitis.

Lacto-N-fucopentaose III found on Schistosoma mansoni egg antigens functions as adjuvant for proteins by inducing Th2-type response.

We have recently demonstrated that induction of Th2 responses by Schistosoma mansoni egg Ag is largely due to carbohydrates on the Ag functioning as adjuvants. Lacto-N-fucopentaose III (LNFPIII), a polylactosamine sugar, is the predominant carbohydrate found in S. mansoni egg Ag. Therefore, using neoglycoprotein, we investigated whether LNFPIII induces in vivo Th2 response and functions as an adjuvant. Following intranasal immunization with LNFPIII linked to human serum albumin (HSA) (HSA-LNFPIII), BALB/c mice mounted a strong Th2 response and produced significantly higher levels of total IgE as well as HSA-specific IgG, IgG1, and IgE. HSA-LNFPIII was over 1000-fold more potent in inducing Ab production as compared with HSA alone. Although LNFPIII itself did not function as an epitope for either IgG or IgE, its conjugation with protein was essential for the adjuvant activity. Moreover, fucose residue on LNFPIII was crucial for induction of Ab production. Nasal lymphocytes from mice immunized with HSA-LNFPIII produced IL-4, IL-5, and IL-10, but not IFN-gamma following in vitro stimulation with HSA or HSA-LNFPIII. In addition, these activated nasal lymphocytes also showed a significant increase of B7-2 expression on B220-positive cells. Furthermore, not only intranasal but also both i.p. and s.c. immunization with HSA-LNFPIII induced significant production of HSA-specific Abs compared with the immunization with HSA alone, suggesting that the activity of LNFPIII was not restricted on particular route of immunization. These results demonstrate that Lewis type carbohydrate LNFPIII can function as an adjuvant by their ability to induce a Th2 response.

Chemokine Expression Dynamics in Mycobacterial (Type-1) and Schistosomal (Type-2) Antigen-Elicited Pulmonary Granuloma Formation

Transcript expression of 24 chemokines (CKs) was examined throughout 8 days in mouse lungs with type-1 (Th1) or type-2 (Th2) cytokine-mediated granulomas induced by bead-immobilized mycobacterial purified protein derivative or Schistosoma mansoni egg antigens. Where possible, CK protein levels were also measured. In addition, we examined effects of in vivo cytokine depletions. Findings were as follows: 1) bead challenge induced increases in 18 of 24 CK transcripts with type-1 and type-2 responses displaying different patterns. CKs fell into four categories: a) type-1-dominant (gamma-interferon-inducible protein (IP-10), monokine induced by INF-gamma (MIG), macrophage inflammatory protein-2 (MIP-2), lipopolysaccharide-induced chemokine (LIX), rodent growth-related oncogene homologue (KP), macrophage inflammatory protein-1alpha (MIP-1alpha) and -1beta (MIP-1beta), lymphotactin), b) type-2-dominant (eotaxin, monocyte chemotactic protein-2 (MCP-2) and -3 (MCP-3), liver and activation-regulated chemokine (LARC), T cell activation protein-3 (TCA-3), c) type-1 and type-2 co-dominant (MCP-1, MCP-5, monocyte-derived chemokine (MDC), thymus and activation-related chemokine (TARC), C10), and d) constitutive (lungkine, secondary lymphoid-tissue chemokine (SLC), EBI1-ligand chemokine (ELC), fractalkine, macrophage inflammatory protein-1gamma (MIP1-gamma), and stromal cell derived factor-1alpha (SDF1-alpha). 2) CKs displayed characteristic temporal patterns. CXC (IP-10, MIG, MIP-2, LIX, KC) and certain CC (MCP-1, MCP-5, MIP-1alpha, MIP-1beta) CKs were produced maximally within 1 to 2 days. Others (MCP-2, MCP-3, eotaxin, lymphotactin, LARC, TCA-3) displayed peak expression later. 3) Interferon-gamma neutralization profoundly abrogated MIG, but had little effect on other CKs. Tumor necrosis factor-alpha neutralization caused up to 50% reduction in a range of CKs. These findings indicate that type-1 and type-2 granulomas display characteristic CK profiles with coordinated expression that is under cytokine-mediated regulation.

TheSchistosoma mansoniegg-derived r38 peptide-induced Th1 response affects the synchronous pulmonary but not the asynchronous hepatic granuloma growth

The p38 peptide derived from Schistosoma mansoni egg-antigens (SEA) is a preferential inducer of the Th1 response. In the present study, we investigated whether induction of a p38-specific Th1 or Th2 response can influence granuloma development in infected or sensitized mice. Mice sensitized with SEA/IL-12 3 weeks after infection but before worm oviposition commenced developed Th1 cytokine responses and had significantly reduced hepatic granuloma size. Similar immunization with p38/IL-12 induced a strong peptide-specific Th1, mixed SEA-specific Th1/Th2 responses without effect on hepatic granuloma development. Presentation of p38 with alum or alum/IL-12 mixture enhanced Th2 cytokine responses and hepatic granuloma sizes. In the synchronized pulmonary model, sensitization of naïve mice with p38/IL-12 induced a strong Th1 cytokine production to p38 and SEA, led to a moderate increase in granuloma growth at days 4 and 8 following egg injection and actually promoted the resolution of the lesion by day 16. Sensitization with p38 in alum induced Th2 cytokine production and generated the largest granulomas whereas the p38/alum/IL-12 sensitized group showed intermediate results in cytokine production and granuloma growth. Thus, in infected mice, the p38 induced strong Th1 response was insufficient to cross-regulate the evolving Th2 environment that generated large granulomas.

Apoptose na modulação da resposta inflamatória aos ovos do Schistosoma mansoni

Foram estudadas 42 amostras de fígado de camundongos inoculados com cercárias do Schistosoma mansoni, obtidas 40, 60, 80 e 120 dias após a infecção e processadas rotineiramente. As lâminas obtidas foram coradas pela HE para análise qualitativa e morfométrica do número e área dos granulomas e pelo MGP para quantificação de células apoptóticas. Os animais com 40 dias de inoculação possuíam menos granulomas/lâmina (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 11,78±4,01), com áreas pequenas (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 52.713,88±5.244,34<FONT FACE="Symbol">m</font>m²) e as menores médias de apoptose (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 7,50±0.99). Os animais com 60 dias de inoculação tiveram os maiores granulomas (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 114.851,20±5.517,20mim²), em maior número (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 92,88±10,62) e freqüente apoptose (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 18,73±1,35). Os com 80 dias de inoculação apresentaram diminuição no tamanho dos granulomas (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 89.305,57±6.162,79mim²), mas grande quantidade deles (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 131,09±15,60) e freqüência maior de apoptose (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 19,93±1,49). Com 120 dias, a apoptose continuou freqüente (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 19,84±1,88), os granulomas eram mais numerosos (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 231,20±34,57), porém menores (<img src="http:/img/fbpe/abmvz/v52n6/a06img01.gif" alt="a06img01.gif (532 bytes)" align="absmiddle" > ou = 41.556,58±2.043,60mim²). A ocorrência de apoptose ajuda a explicar a redução na celularidade e a conseqüente diminuição da área dos granulomas. A apoptose foi confirmada histologicamente pela técnica de "tunel". Assim, a apoptose participa da modulação do fenômeno inflamatório do tipo granulomatoso, reacional à embolização de ovos do parasito no fígado. Com a evolução da doença, desenvolve-se uma tolerância imunológica aos antígenos do ovo do Schistosoma mansoni, evidenciada morfologicamente pela diminuição da área média dos granulomas e pela maior freqüência de apoptose nas células componentes do granuloma.

Enzyme activities in Schistosoma mansoni soluble egg antigen.

Schistosoma mansoni egg antigens are mostly responsible for the granulomatous pathology in human intestinal schistosomiasis. Several previous studies have indicated that the induction of an immune response against some parasite enzymes may protect against pathology. The present work was designed to identify enzyme activities present in a standard soluble egg antigen (SEA) preparation. Simple colorimetric analyses were performed incubating SEA with 2-naphthyl, 2-naphthylamide (2NA), or p-nitrophenyl substrates at different pHs in the absence of added effectors. Results showed prominent acid phosphatase (pH 5.4), alkaline phosphatase (pH 8.5), and N-acetyl-beta-glucosaminidase (pH 5.4) activities. Relevant peptidase activities were also detected at pH 6.5-7.5 against 2NA derivatives of (1) aliphatic (alpha-Ala > beta-Ala > Leu > Met > S-benzyl-Cys), polar (Ser > Gln), basic (Arg > Lys > ornithine), and acidic (Glu) amino acids; (2) dipeptides: X-Ala (X = Gly > Leu > Lys > Asp), X-Arg (X = Ala > Arg > Phe > Gly > Pro > Asp), Ser-Met, and Phe-Pro; and (3) tripeptides (Ala-Phe-Pro > Phe-Pro-Ala). The data demonstrated that S. mansoni SEA contains a rich set of hydrolases with different specificities that might play a role in the egg physiology and possibly also in the host-parasite relationships.