SINAPs: A Software Tool for Analysis and Visualization of Interaction Networks of Molecular Dynamics Simulations

As long as the structural study of molecular mechanisms requires multiple molecular dynamics reflecting contrasted bioactive states, the subsequent analysis of molecular interaction networks remains a bottleneck to be fairly treated and requires a user-friendly 3D view of key interactions. Structural Interaction Network Analysis Protocols (SINAPs) is a proprietary python tool developed to (i) quickly solve key interactions able to distinguish two protein states, either from two sets of molecular dynamics simulations or from two crystallographic structures, and (ii) render a user-friendly 3D view of these key interactions through a plugin of UCSF Chimera, one of the most popular open-source viewing software for biomolecular systems. Through two case studies, glucose transporter-1 (GLUT-1) and A2A adenosine receptor (A2AR), SINAPs easily pinpointed key interactions observed experimentally and relevant for their bioactivities. This very effective tool was thus applied to identify the amino acids involved in the molecular enzymatic mechanisms ruling the activation of an immunomodulator drug candidate, P28 glutathione-S-transferase (P28GST). SINAPs is freely available at https://github.com/ParImmune/SINAPs.

A new instrument for kinetics and branching ratio studies of gas phase collisional processes at very low temperatures

A new instrument dedicated to the kinetic study of low-temperature gas phase neutral-neutral reactions, including clustering processes, is presented. It combines a supersonic flow reactor with vacuum ultra-violet synchrotron photoionization time-of-flight mass spectrometry. A photoion-photoelectron coincidence detection scheme has been adopted to optimize the particle counting efficiency. The characteristics of the instrument are detailed along with its capabilities illustrated through a few results obtained at low temperatures (<100 K) including a photoionization spectrum of n-butane, the detection of formic acid dimer formation, and the observation of diacetylene molecules formed by the reaction between the C₂H radical and C₂H₂.

AllergoOncology: ultra-low IgE, a potential novel biomarker in cancer-a Position Paper of the European Academy of Allergy and Clinical Immunology (EAACI)

Elevated serum IgE levels are associated with allergic disorders, parasitosis and specific immunologic abnormalities. In addition, epidemiological and mechanistic evidence indicates an association between IgE-mediated immune surveillance and protection from tumour growth. Intriguingly, recent studies reveal a correlation between IgE deficiency and increased malignancy risk. This is the first review discussing IgE levels and links to pathological conditions, with special focus on the potential clinical significance of ultra-low serum IgE levels and risk of malignancy. In this Position Paper we discuss: (a) the utility of measuring total IgE levels in the management of allergies, parasitosis, and immunodeficiencies, (b) factors that may influence serum IgE levels, (c) IgE as a marker of different disorders, and d) the relationship between ultra-low IgE levels and malignancy susceptibility. While elevated serum IgE is generally associated with allergic/atopic conditions, very low or absent IgE may hamper anti-tumour surveillance, indicating the importance of a balanced IgE-mediated immune function. Ultra-low IgE may prove to be an unexpected biomarker for cancer risk. Nevertheless, given the early stage of investigations conducted mostly in patients with diseases that influence IgE levels, in-depth mechanistic studies and stratification of malignancy risk based on associated demographic, immunological and clinical co-factors are warranted.

Treatment with P28GST, a schistosome-derived enzyme, after acute colitis induction in mice: Decrease of intestinal inflammation associated with a down regulation of Th1/Th17 responses

Background

P28GST, a 28Kd glutathione S-transferase enzymatic protein derived from a schistosome helminth prevents experimental colitis when administered subcutaneously in the presence of adjuvant by decreasing pro-inflammatory Th1/Th17 response. Given the antioxidant properties of P28GST, we evaluated its anti-inflammatory potential when administered locally after colitis induction in the absence of adjuvant.

Methods

Colitis was induced in BALB/c mice by rectal administration of TNBS, followed by two intraperitoneal injections of P28GST at day 1 and day 2. Mice were sacrificed 48h after TNBS administration and evaluated for macroscopic and histological scores, myeloperoxidase (MPO) quantification and cytokine messenger RNA expression in the colonic tissues.

Results

Both clinical and histological scores significantly decreased in mice treated with P28GST at 5 or 50μg/kg when compared to vehicle- treated mice. A significant reduction of MPO was detected in colonic tissues from P28GST–treated mice, similarly to mice treated with methylprednisolone as the reference treatment. Pro-inflammatory cytokines TNF, IL-1β, and IL-6, mRNA as well as serum levels were down-regulated in mice colonic tissues treated with P28GST at 5 or 50μg/kg. In addition, a significant decrease of mRNA expression levels of T-bet, and ROR-γ, respective markers of Th1 and Th17 cells was observed. Whereas no significant effect was detected on Gata3 mRNA, a marker of Th2 cells, the Arg/iNOS mRNA levels significantly increased in P28GST-treated mice, suggesting the induction of M2 macrophages.

Conclusions

These findings provide evidence that P28GST injected locally after colitis induction induces a potent decrease of colitis inflammation in mice, associated to downregulation of Th1/Th17 response, and induction of anti-inflammatory alternatively activated macrophages.

Safety and efficacy of the rSh28GST urinary schistosomiasis vaccine: A phase 3 randomized, controlled trial in Senegalese children

Background

Urinary schistosomiasis, the result of infection by Schistosoma haematobium (Sh), remains a major global health concern. A schistosome vaccine could represent a breakthrough in schistosomiasis control strategies, which are presently based on treatment with praziquantel (PZQ). We report the safety and efficacy of the vaccine candidate recombinant 28-kDa glutathione S-transferase of Sh (rSh28GST) designated as Bilhvax, in a phase 3 trial conducted in Senegal.

Methods and findings

After clearance of their ongoing schistosomiasis infection with two doses of PZQ, 250 children aged 6–9 years were randomized to receive three subcutaneous injections of either rSh28GST/Alhydrogel (Bilhvax group) or Alhydrogel alone (control group) at week 0 (W0), W4, and W8 and then a booster at W52 (one year after the first injection). PZQ treatment was given at W44, according to previous phase 2 results. The primary endpoint of the analysis was efficacy, evaluated as a delay of recurrence of urinary schistosomiasis, defined by a microhematuria associated with at least one living Sh egg in urine from baseline to W152. During the 152-week follow-up period, there was no difference between study arms in the incidence of serious adverse events. The median follow-up time for subjects without recurrence was 22.9 months for the Bilhvax group and 18.8 months for the control group (log-rank p = 0.27). At W152, 108 children had experienced at least one recurrence in the Bilhvax group versus 112 in the control group. Specific immunoglobulin (Ig)G1, IgG2, and IgG4, but not IgG3 or IgA titers, were increased in the vaccine group.

Conclusions

While Bilhvax was immunogenic and well tolerated by infected children, a sufficient efficacy was not reached. The lack of effect may be the result of several factors, including interference by individual PZQ treatments administered each time a child was found infected, or the chosen vaccine-injection regimen favoring blocking IgG4 rather than protective IgG3 antibodies. These observations contrasting with results obtained in experimental models will help in the design of future trials.

Trial registration

ClinicalTrials.gov NCT 00870649

Vaccines represent an attractive tool in the fight against schistosomiasis. Pre-clinical immunization studies with the schistosome enzyme 28 kDa glutathione S-transferase (28GST) have shown a significant reduction of schistosome egg production and subsequent pathology. The objective of the present phase 3 trial was to assess the efficacy and safety of vaccination with the recombinant 28GST of Schistosoma haematobium (rSh28GST) named Bilhvax, in infected school children. After Praziquantel treatment before inclusion and three administrations of rSh28GST at one month interval as primo-vaccination, subjects received a boost injection one year after the first administration. The efficacy was evaluated as a delay of recurrence of urinary schistosomiasis. While immunological analysis showed that Bilhvax induced a consistent immune response characterized by antibodies able to inhibit 28GST enzymatic activity, the efficacy endpoint was not reached. This lack of significant effect may be due to the negative conjunction of a too challenging recurrence criterion associated with safety measures ensuring repeated PZQ treatment. The control of these main factors will be essential for the subsequent trials and must provide evidence of the Bilhvax efficacy as a safe vaccine against uro-genital schistosomiasis.

Impact of allergy on phenotypic and endotypic profiles of nasal polyposis

OBJECTIVES

To assess the impact of allergy on clinical presentations (phenotypes) and inflammatory patterns (endotypes) of chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

A single-center prospective study was conducted over an 18-month period. Fifty-seven patients with refractory CRSwNP were included. The diagnosis of allergy was based on concordant skin prick tests and symptoms. Phenotypes were determined on symptom severity score, polyp size classification and Lund-Mackay CT staging. Inflammatory endotypes were determined on biomarker analysis (IgE, IgA, IL-5, IL-9, ECP, EDN) in blood and nasal secretions. Eosinophil counts were obtained in blood, nasal secretions and polyps.

RESULTS

Phenotype and endotype profiles were comparable in patients with (n=15) or without (n=42) allergy. Only asthma with high total IgE blood concentration showed association with allergy.

CONCLUSIONS

The present results suggest that allergy is not directly involved in the clinical expression and specific inflammatory pathways of CRSwNP. New therapies target inflammation signaling pathways, and identifying accurate blood and tissue biomarkers will be the line of research most likely to improve treatment of CRSwNP.

Preparation and investigation of P28GST-loaded PLGA microparticles for immunomodulation of experimental colitis

The aim of this work was to prepare and characterize (in vitro and in vivo) PLGA-based microparticles loaded with an enzymatic protein derived from the helminth parasite Schistosoma haematobium: glutathione S-transferase P28GST (P28GST). This protein is not only a promising candidate vaccine against schistosomiasis, it also exhibits interesting immunomodulating effects, which can be helpful for the regulation of inflammatory diseases. Helminths express a regulatory role on intestinal inflammation, and immunization by P28GST has recently been shown to be as efficient as infection to reduce inflammation in a murine colitis model. As an alternative to the combination with a classical adjuvant, long acting P28GST microparticles were prepared in order to induce colitis prevention. PLGA was used as biodegradable and biocompatible matrix former, and a W/O/W emulsion/solvent extraction technique applied to prepare different types of microparticles. The effects of key formulation and processing parameters (e.g., the polymer molecular weight, drug loading, W/O/W phase volumes and stirring rates of the primary/secondary emulsions) on the systems' performance were studied. Microparticles providing about constant P28GST release during several weeks were selected and their effects in an experimental model of colitis evaluated. Mice received P28GST-loaded or P28GST-free PLGA microparticles (s.c.) on Day 0, and optionally also on Days 14 and 28. Colitis was induced on Day 35, the animals were sacrificed on Day 37. Interestingly, the Wallace score (being a measure of the severity of the inflammation) was significantly lower in mice treated with P28GST microparticles compared to placebo after 1 or 3 injections. As immunogenicity markers, increased anti-P28GST IgG levels were detected after three P28GST PLGA microparticle injections, but not in the control groups. Thus, the proposed microparticles offer an interesting potential for the preventive treatment of experimental colitis, while the underlying mechanism of action is still to be investigated.

AllergoOncology - the impact of allergy in oncology: EAACI position paper

Th2 immunity and allergic immune surveillance play critical roles in host responses to pathogens, parasites and allergens. Numerous studies have reported significant links between Th2 responses and cancer, including insights into the functions of IgE antibodies and associated effector cells in both antitumour immune surveillance and therapy. The interdisciplinary field of AllergoOncology was given Task Force status by the European Academy of Allergy and Clinical Immunology in 2014. Affiliated expert groups focus on the interface between allergic responses and cancer, applied to immune surveillance, immunomodulation and the functions of IgE-mediated immune responses against cancer, to derive novel insights into more effective treatments. Coincident with rapid expansion in clinical application of cancer immunotherapies, here we review the current state-of-the-art and future translational opportunities, as well as challenges in this relatively new field. Recent developments include improved understanding of Th2 antibodies, intratumoral innate allergy effector cells and mediators, IgE-mediated tumour antigen cross-presentation by dendritic cells, as well as immunotherapeutic strategies such as vaccines and recombinant antibodies, and finally, the management of allergy in daily clinical oncology. Shedding light on the crosstalk between allergic response and cancer is paving the way for new avenues of treatment.

Periodontal manifestations of inflammatory bowel disease: emerging epidemiologic and biologic evidence

Inflammatory bowel disease and periodontitis are both described as a disproportionate mucosal inflammatory response to a microbial environment in susceptible patients. Moreover, these two conditions share major environmental and lifestyle-related risk factors. Despite this intriguing pathogenic parallel, large-scale studies and basic research have only recently considered periodontal outcomes as relevant data. There are mounting and consistent arguments, from recent epidemiologic studies and animal models, that these two conditions might be related. This article is a comprehensive and critical up-to-date review of the current evidence and future prospects in understanding the biologic and epidemiologic relationships between periodontal status and inflammatory bowel disease.

Low Temperature Kinetics of the First Steps of Water Cluster Formation

We present a combined experimental and theoretical low temperature kinetic study of water cluster formation. Water cluster growth takes place in low temperature (23-69 K) supersonic flows. The observed kinetics of formation of water clusters are reproduced with a kinetic model based on theoretical predictions for the first steps of clusterization. The temperature- and pressure-dependent association and dissociation rate coefficients are predicted with an ab initio transition state theory based master equation approach over a wide range of temperatures (20-100 K) and pressures (10^{-6}-10  bar).

Direct dehydration of 1,3-butanediol into butadiene over aluminosilicate catalysts

The catalytic dehydration of 1,3-butanediol into butadiene was investigated over various aluminosilicates with different SiO₂/Al₂O₃ ratios and pore architectures.

Performance of Ag/Al2O3 catalysts in the liquid phase oxidation of glycerol – effect of preparation method and reaction conditions

A series of silver supported catalysts have been developed and proposed for mild oxidation of glycerol in the liquid phase. High selectivity to glycolic acid, stability in both continuous-flow and periodic mode of reaction, and good resistance to crude glycerol impurities have been achieved.

IL-18 Is Involved in Eosinophil-Mediated Tumoricidal Activity against a Colon Carcinoma Cell Line by Upregulating LFA-1 and ICAM-1

Eosinophils are multifunctional leukocytes that are involved in innate and adaptive immune responses through the expression of various receptors and mediators. Previously, we showed that human eosinophils and T cells shared cytotoxic activities against tumor cells that involved the γ-δ TCR and cell-cell contact. In this study, we investigated the molecules involved in eosinophil-tumor cell interactions. Given the role of IL-18 in cell adhesion and in protecting against colon cancer, we evaluated its role in eosinophil-mediated cytotoxicity against Colo-205, a human colon carcinoma cell line. We found that human eosinophils exerted dose- and time-dependent tumoricidal activity against Colo-205 cells. Neutralization of IL-18 significantly reduced eosinophil-mediated Colo-205 apoptosis and inhibited cell-cell adhesion. Moreover, addition of rIL-18 led to upregulation of CD11a and ICAM-1 adhesion molecules, which were involved in the contact between eosinophils and Colo-205 cells. Our results indicated that IL-18 was involved in the eosinophil-mediated death of Colo-205 by facilitating contact between effector and target cells. These data underscored the involvement of an additional mediator in eosinophil-mediated antitumor cytotoxicity. Our findings support existing evidence that eosinophils could play a beneficial role in the context of colon cancer.

Immune profile modulation of blood and mucosal eosinophils in nasal polyposis with concomitant asthma

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is frequently associated with asthma. Mucosal eosinophil (EO) infiltrate has been found to correlate with asthma and disease severity but not necessarily in every patient. Other multifactorial immune processes are required to determine disease endotypes and response to treatment.

OBJECTIVE

To evaluate EO immunomodulation for migration and survival in accordance with inflammatory protein profiles and asthmatic status in CRSwNP.

METHODS

Ninety-three patients (47 with asthma) with CRSwNP were included. Each patient was staged clinically according to symptom severity and polyp size. Nasal secretions were collected to establish a cytokine profile. The EOs were purified from blood samples and nasal polyps to delineate specific immunophenotypes by flow cytometry and determine in vitro EO survival in relation to asthmatic status.

RESULTS

The CRSwNP in patients with asthma was characterized by eosinophilia and a high level of interleukin (IL)-5 in nasal secretions. Although EOs exhibited activation profiles after mucosal migration, there was relative down-expression of IL-5 receptor-α (IL-5Rα) on nasal EOs in patients with asthma. The EO culture with IL-5 and IL-9 showed an antiapoptotic effect in patients with asthma through IL-5Rα modulation.

CONCLUSION

Mucosal eosinophilia seems to be induced by EO nasal trapping through modulation of adhesion receptors. In patients with asthma, EO involvement is enhanced by the antiapoptotic synergistic action of T-helper cell type 2 cytokines on IL-5Rα expression. This study shows for the first time that IL-9 is involved in EO homeostasis in CRSwNP and could explain the low benefit of anti-IL-5 therapy for some patients with asthma and nasal polyposis.

CD3-CD4+ lymphoid variant of hypereosinophilic syndrome: nodal and extranodal histopathological and immunophenotypic features of a peripheral indolent clonal T-cell lymphoproliferative disorder

The CD3(-)CD4(+) lymphoid variant of hypereosinophilic syndrome is characterized by hypereosinophilia and clonal circulating CD3(-)CD4(+) T cells. Peripheral T-cell lymphoma has been described during this disease course, and we observed in our cohort of 23 patients 2 cases of angio-immunoblastic T-cell lymphoma. We focus here on histopathological (n=12 patients) and immunophenotypic (n=15) characteristics of CD3(-)CD4(+) lymphoid variant of hypereosinophilic syndrome. Atypical CD4(+) T cells lymphoid infiltrates were found in 10 of 12 CD3(-)CD4(+) L-HES patients, in lymph nodes (n=4 of 4 patients), in skin (n=9 of 9) and other extra-nodal tissues (gut, lacrymal gland, synovium). Lymph nodes displayed infiltrates limited to the interfollicular areas or even an effacement of nodal architecture, associated with proliferation of arborizing high endothelial venules and increased follicular dendritic cell meshwork. Analysis of 2 fresh skin samples confirmed the presence of CD3(-)CD4(+) T cells. Clonal T cells were detected in at least one tissue in 8 patients, including lymph nodes (n=4 of 4): the same clonal T cells were detected in blood and in at least one biopsy, with a maximum delay of 23 years between samples. In the majority of cases, circulating CD3(-)CD4(+) T cells were CD2(hi) (n=9 of 14), CD5(hi) (n=12 of 14), and CD7(-)(n=4 of 14) or CD7(low) (n=10 of 14). Angio-immunoblastic T-cell lymphoma can also present with CD3(-)CD4(+) T cells; despite other common histopathological and immunophenotypic features, CD10 expression and follicular helper T-cell markers were not detected in lymphoid variant of hypereosinophilic syndrome patients, except in both patients who developed angio-immunoblastic T-cell lymphoma, and only at T-cell lymphoma diagnosis. Taken together, persistence of tissular clonal T cells and histopathological features define CD3(-)CD4(+) lymphoid variant of hypereosinophilic syndrome as a peripheral indolent clonal T-cell lymphoproliferative disorder, which should not be confused with angio-immunoblastic T-cell lymphoma.

From parasites to allergy: a second receptor for IgE

Human allergic responses are triggered when mast cells bind IgE antibodies. IgE production is also a regular feature of helminth infection and parasites can be killed by inflammatory cells such as macrophages, eosinophils and platelets sensitized by reaginic antibody. The IgE receptor they use has been identified only recently. Here André Capron and his colleagues discuss how it differs from the IgE receptor present on mast cells.

The lymphoid variant of hypereosinophilic syndrome: study of 21 patients with CD3-CD4+ aberrant T-cell phenotype

The CD3-CD4+ aberrant T-cell phenotype is the most described in the lymphoid variant of hypereosinophilic syndrome (L-HES), a rare form of HES. Only a few cases have been reported, and data for these patients are scarce. To describe characteristics and outcome of CD3-CD4+ L-HES patients, we conducted a national multicentric retrospective study in the French Eosinophil Network. All patients who met the recent criteria of hypereosinophilia (HE) or HES and who had a persistent CD3-CD4+ T-cell subset on blood T-cell phenotyping were included. Clinical and laboratory data were retrospectively collected by chart review. CD3-CD4+ L-HES was diagnosed in 21 patients (13 females, median age 42 years [range, 5-75 yr]). Half (48%) had a history of atopic manifestations. Clinical manifestations were dermatologic (81%), superficial adenopathy (62%), rheumatologic (29%), gastrointestinal (24%), pulmonary (19%), neurologic (10%), and cardiovascular (5%). The median absolute CD3-CD4+ T-cell count was 0.35 G/L (range, 0.01-28.3), with a clonal TCRγδ rearrangement in 76% of patients. The mean follow-up duration after HES diagnosis was 6.9 ± 5.1 years. All patients treated with oral corticosteroids (CS) (n = 18) obtained remission, but 16 required CS-sparing treatments. One patient had a T-cell lymphoma 8 years after diagnosis, and 3 deaths occurred during follow-up.In conclusion, clinical manifestations related to CD3-CD4+ T cell-associated L-HES are not limited to skin, and can involve all tissue or organs affected in other types of HE. Contrary to FIP1L1-PDGFRA chronic eosinophilic leukemia patients, CS are always effective in these patients, but CS-sparing treatments are frequently needed. The occurrence of T-cell lymphoma, although rare in our cohort, remains a major concern during follow-up.

Gas flow in plant microfluidic networks controlled by capillary valves

The xylem vessels of trees constitute a model natural microfluidic system. In this work, we have studied the mechanism of air flow in the Populus xylem. The vessel microstructure was characterized by optical microscopy, transmission electronic microscopy (TEM), and atomic force microscopy (AFM) at different length scales. The xylem vessels have length ≈15 cm and diameter ≈20μm. Flow from one vessel to the next occurs through ∼102 pits, which are grouped together at the ends of the vessels. The pits contain a thin, porous pit membrane with a thickness of 310 nm. We have measured the Young's moduli of the vessel wall and of the pits (both water-saturated and after drying) by specific nanoindentation and nanoflexion experiments with AFM. We found that both the dried and water-saturated pit membranes have Young's modulus around 0.4 MPa, in agreement with values obtained by micromolding of pits deformed by an applied pressure difference. Air injection experiments reveal that air flows through the xylem vessels when the differential pressure across a sample is larger than a critical value ΔPc=1.8 MPa. In order to model the air flow rate for ΔP⩾ΔPc, we assumed the pit membrane to be a porous medium that is strained by the applied pressure difference. Water menisci in the pit pores play the role of capillary valves, which open at ΔP=ΔPc. From the point of view of the plant physiology, this work presents a basic understanding of the physics of bordered pits.

The Spectrum of FIP1L1-PDGFRA-Associated Chronic Eosinophilic Leukemia: New Insights Based on a Survey of 44 Cases

Imatinib is the treatment of choice for FIP1L1/PDGFRA (F/P)-associated chronic eosinophilic leukemia (F/P CEL), but its optimal dosing, duration, and possibility of discontinuation are still a matter of debate. A retrospective multicenter study was conducted with 44 F/P CEL patients identified in the French Eosinophil Network and treated with imatinib. The most frequently involved systems were skin (57%), spleen (52%), and lung (45%), and eosinophilic heart disease was observed in 15 patients (34%). Complete hematologic response (CHR) was obtained in all patients, and complete molecular response (CMR) in 95% of patients (average initial imatinib dose, 165 mg/d). For 29 patients the imatinib dose was tapered with a maintenance dose of 58 mg/d (±34 mg/d), allowing sustained CHR and CMR. None of the patients developed resistance during a median follow-up of 52.3 months (range, 1.4-97.4 mo). Imatinib was stopped in 11 patients; 6 of the patients subsequently relapsed, but 5 remained in persistent CHR or CMR (range, 9-88 mo). These results confirm that an initial low-dose regimen of imatinib (100 mg/d) followed by a lower maintenance dose can be efficient for obtaining long-term CHR and CMR. Our data also suggest that imatinib can be stopped in some patients without molecular relapse.

Formations of dumbbell C118 and C119 inside clusters of C60 molecules by collision with α particles

We report highly selective covalent bond modifications in collisions between keV alpha particles and van der Waals clusters of C(60) fullerenes. Surprisingly, C(119)(+) and C(118)(+) are the dominant molecular fusion products. We use molecular dynamics simulations to show that C(59)(+) and C(58)(+) ions--effectively produced in prompt knockout processes with He(2+)--react rapidly with C(60) to form dumbbell C(119)(+) and C(118)(+). Ion impact on molecular clusters in general is expected to lead to efficient secondary reactions of interest for astrophysics. These reactions are different from those induced by photons.

Safety and immunogenicity of rSh28GST antigen in humans: phase 1 randomized clinical study of a vaccine candidate against urinary schistosomiasis

BACKGROUND

Treatment of urinary schistosomiasis by chemotherapy remains challenging due to rapid re-infection and possibly to limited susceptibility to praziquantel treatment. Therefore, therapeutic vaccines represent an attractive alternative control strategy. The objectives of this study were to assess the safety and tolerability profile of the recombinant 28 kDa glutathione S-transferase of Schistosoma haematobium (rSh28GST) in healthy volunteers, and to determine its immunogenicity.

METHODOLOGY

Volunteers randomly received 100 µg rSh28GST together with aluminium hydroxide (Alum) as adjuvant (n = 8), or Alum alone as a comparator (n = 8), twice with a 28-day interval between doses. A third dose of rSh28GST or Alum alone was administered to this group at day 150. In view of the results obtained, another group of healthy volunteers (n = 8) received two doses of 300 µg of rSh28GST, again with a 28-day interval. A six-month follow-up was performed with both clinical and biological evaluations. Immunogenicity of the vaccine candidate was evaluated in terms of specific antibody production, the capacity of sera to inhibit enzymatic activity of the antigen, and in vitro cytokine production.

PRINCIPAL FINDINGS

Among the 24 healthy male participants no serious adverse events were reported in the days or weeks after administration. Four subjects under rSh28GST reported mild reactions at the injection site while a clinically insignificant increase in bilirubin was observed in 8/24 subjects. No hematological nor biochemical evidence of toxicity was detected. Immunological analysis showed that rSh28GST was immunogenic. The induced Th2-type response was characterized by antibodies capable of inhibiting the enzymatic activity of rSh28GST.

CONCLUSIONS

rSh28GST in Alum did not induce any significant toxicity in healthy adults and generated a Th2-type immune response. Together with previous preclinical results, the data of safety, tolerability and quality of the specific immune response provide evidence that clinical trials with rSh28GST could be continued in humans as a potential vaccine candidate against urinary schistosomiasis.

Involvement of eosinophils in the anti-tumor response

Eosinophils have long been associated with allergy and parasitic infections. Today, they are considered as multifunctional leukocytes, which participate both in innate and adaptive immune response though the expression of various receptors and mediators. Although the tumor-associated eosinophilia is observed for a long time in many hematological and solid malignancies, with a generally good prognosis value, there is a lack of knowledge on the different mechanisms involved in this phenomenon. Moreover, the recent discovery in human eosinophils of different receptors and mediators, shared with lymphocytes and involved in anti-tumor defense, suggests that eosinophils can play a role in anti-tumoral immunity. We review in the present paper the current knowledge on epidemiology, recruitment, and mechanisms involved in the response of eosinophils toward tumors.

Effect of parasite infection on allergic disease

Vertebrates and helminths have co-evolved for 500 million years, developing mutual adaptation mechanisms between parasites and hosts. Today, however, helminth diseases are among the most neglected communicable diseases. Epidemiological evidence shows that exposure to helminth parasites is inversely correlated with allergy incidence, and helminths induce immune hyporeactivity in both the innate and adaptive systems. The mechanisms include parasite-derived regulatory molecules, the study of which opens new avenues for the control of allergic and autoimmune diseases.

Ions colliding with cold polycyclic aromatic hydrocarbon clusters

We report the first experimental study of ions interacting with clusters of polycyclic aromatic hydrocarbon (PAH) molecules. Collisions between 11.25 keV 3He+ or 360 keV 129Xe20+ and weakly bound clusters of one of the smallest PAH molecules, anthracene, show that C14H10 clusters have much higher tendencies to fragment in ion collisions than other weakly bound clusters. The ionization is dominated by peripheral collisions in which the clusters, very surprisingly, are more strongly heated by Xe20+ collisions than by He+ collisions. The appearance size is k=15 for [C ₁₄H₁₀](k)2+.

Human eosinophils exert TNF-α and granzyme A-mediated tumoricidal activity toward colon carcinoma cells

Peripheral blood and tissue eosinophilia is a prominent feature in allergic diseases and helminth infections. In cancer patients, tumor-associated tissue eosinophilia is frequently observed. Tumor-associated tissue eosinophilia can be associated with a favorable prognosis, notably in colorectal carcinoma. However, underlying mechanisms of eosinophil contribution to antitumor responses are poorly understood. We have in this study investigated the direct interactions of human eosinophils with Colo-205, a colorectal carcinoma cell line, and show that eosinophils induce apoptosis and directly kill tumor cells. Using blocking Abs, we found that CD11a/CD18 complex is involved in the tumoricidal activity. Coculture of eosinophils with Colo-205 led to the release of eosinophil cationic protein and eosinophil-derived neurotoxin as well as TNF-α secretion. Moreover, eosinophils expressed granzyme A, which was released upon interaction with Colo-205, whereas cytotoxicity was partially inhibited by FUT-175, an inhibitor of trypsin-like enzymatic activity. Our data present the first demonstration, to our knowledge, that granzyme A is a cytotoxic mediator of the eosinophil protein arsenal, exerting eosinophil tumoricidal activity toward Colo-205, and provide mechanistic evidence for innate responses of eosinophil against tumor cells.

[Eosinophil: a new effector of innate immunity?]

The eosinophil leukocyte has long been considered as a second class cell. It appears now that its functions extend far beyond solely the release of cytotoxic mediators involved in a protective role in some parasitic infections or in pathological manifestations during allergic diseases. The recent demonstration that eosinophils express innate immune receptors (TLR, gdTCR) and mediators (a-defensins), in addition to the numerous receptors involved in adaptive immunity, confers to eosinophils the potential to directly recognize danger signals including pathogens. Thus, both such a functional plasticity together with its strategic tissue localization indicate that eosinophils likely play a previously unsuspected role in anti-infectious response.

Antibody and cytokine responses in BALB/c mice immunized with the excreted/secreted proteins of Giardia intestinalis: the role of cysteine proteases

The mechanisms involved in the induction of the immune response in humans or experimental hosts infected with Giardia intestinalis are not well understood. The results of previous studies indicate that the parasite induces a mixed Th1/Th2 response and that, in experimentally infected mice, the parasite's excreted/secreted (E/S) proteins contain cysteine proteases that are recognised by the murine immune system. In the present study, the possible effects of the E/S proteases of G. intestinalis on the host's humoral and cellular immune responses were investigated in BALB/c mice immunized with the parasite's E/S proteins. High titres of specific IgG(1), IgG(2a) and IgE antibodies were detected after immunization with native E/S proteins. Spleen cells stimulated with such proteins in vitro showed a significant antigen-specific proliferative response accompanied by the production of high concentrations of interleukin-4 (IL-4), interleukin-5 (IL-5) and interleukin-10 (IL-10) but little secretion of interferon-gamma (IFN-gamma). When, before use, the proteases in the E/S proteins were inhibited, by heat treatment or the addition of E-64, they elicited much lower titres of specific IgG(1) and IgE in mice while, in splenocytes in vitro, they triggered much lower production of IL-4, IL-5 and IL-10 and reduced antigen-specific proliferation. Since E-64 only inhibits cysteine proteases, these results indicate that the excreted/secreted cysteine proteases of G. intestinalis may be involved in the induction and regulation of a specific immune response in the infected host.

Molecular characterization of a new Tetratrichomonas species in a patient with empyema

A new Tetratrichomonas species was identified by molecular and phylogenetic approaches in the pleural fluid from a patient with encysted empyema leading to dyspnea. This observation raised the questions of the real prevalence of pulmonary trichomonosis in humans, the zoonotic potential of trichomonads, and the existence of human-host-adapted strains.

Eosinophil-derived IFN-gamma induces airway hyperresponsiveness and lung inflammation in the absence of lymphocytes

BACKGROUND

Eosinophils are key players in T(H)2-driven pathologies, such as allergic lung inflammation. After IL-5- and eotaxin-mediated tissue recruitment, they release several cytotoxic and inflammatory mediators. However, their exact contribution to asthma remains controversial. Indeed, in human subjects anti-IL-5 treatment inhibits eosinophilia but not antigen-induced airway hyperresponsiveness (AHR). Likewise, lung fibrosis is abrogated in 2 strains of eosinophil-deficient mice, whereas AHR is inhibited in only one of them. Finally, eosinophils have been shown to attract T(H)2 lymphocytes at the inflammatory site.

OBJECTIVE

The ability of eosinophils to promote AHR and lung inflammation independently of lymphocytes was investigated.

METHODS

Adoptive transfers of resting or activated eosinophils from IL-5 transgenic mice were performed into naive BALB/c mice, mice with severe combined immunodeficiency, and IFN-gamma-deficient BALB/c recipients.

RESULTS

Adoptively transferred eosinophils induced lung inflammation, fibrosis, collagen deposition, and AHR not only in BALB/c mice but also in recipient mice with severe combined immunodeficiency. Surprisingly, IFN-gamma expression was increased in lungs from eosinophil-transferred animals. Furthermore, IFN-gamma neutralization in recipients partially inhibited eosinophil-induced AHR. Moreover, IFN-gamma-deficient eosinophils or eosinophils treated with a blocking anti-IFN-gamma receptor antibody failed to induce AHR in IFN-gamma-deficient recipients. Finally, in vitro and at low concentrations, IFN-gamma increased eosinophil peroxidase release, potentiated chemotaxis, and prolonged survival, suggesting the existence of an autocrine mechanism.

CONCLUSIONS

These results support the important and previously unsuspected contribution of eosinophils to lung inflammation independently of lymphocytes through production of IFN-gamma, the prototypical T(H)1 cytokine.

A functional gammadeltaTCR/CD3 complex distinct from gammadeltaT cells is expressed by human eosinophils

BACKGROUND

Eosinophils are effector cells during parasitic infections and allergic responses. However, their contribution to innate immunity has been only recently unravelled.

METHODOLOGY/PRINCIPAL FINDINGS

Here we show that human eosinophils express CD3 and gammadelta T Cell Receptor (TCR) but not alphabeta TCR. Surface expression of gammadeltaTCR/CD3 is heterogeneous between eosinophil donors and inducible by mycobacterial ligands. Surface immunoprecipitation revealed expression of the full gammadeltaTCR/CD3 complex. Real-time PCR amplification for CD3, gamma and delta TCR constant regions transcripts showed a significantly lower expression in eosinophils than in gammadeltaT cells. Limited TCR rearrangements occur in eosinophils as shown by spectratyping analysis of CDR3 length profiles and in situ hybridization. Release by eosinophils of Reactive Oxygen Species, granule proteins, Eosinophil Peroxidase and Eosinophil-Derived Neurotoxin and cytokines (IFN-gamma and TNF-alpha) was observed following activation by gammadeltaTCR-specific agonists or by mycobacteria. These effects were inhibited by anti-gammadeltaTCR blocking antibodies and antagonists. Moreover, gammadeltaTCR/CD3 was involved in eosinophil cytotoxicity against tumor cells.

CONCLUSIONS/SIGNIFICANCE

Our results provide evidence that human eosinophils express a functional gammadeltaTCR/CD3 with similar, but not identical, characteristics to gammadeltaTCR from gammadeltaT cells. We propose that this receptor contributes to eosinophil innate responses against mycobacteria and tumors and may represent an additional link between lymphoid and myeloid lineages.

Histone deacetylase inhibitors induce apoptosis, histone hyperacetylation and up-regulation of gene transcription in Schistosoma mansoni

In order to explore the conservation/divergence of transcriptional regulation in the platyhelminth parasite Schistosoma mansoni, we are studying the structures and functions of transcriptional mediators and in particular histone-modifying enzymes. Reversible histone acetylation changes chromatin structure and modulates gene transcription. The removal of acetyl residues from histones and other proteins is catalyzed by histone deacetylases (HDACs) that are under increasing study as therapeutic targets, both in cancer and parasitic diseases. In order to determine the extent and importance of histone acetylation in S. mansoni, we tested the effects of three histone deacetylase inhibitors (HDACi) on both larval and adult worms in culture. Trichostatin A (TSA), valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA) inhibited global HDAC activity at all life-cycle stages. TSA and VPA, but not SAHA, caused mortality of schistosomula and adults, with TSA showing the most rapid effect. Moreover, TSA caused an increase in apoptosis in schistosomula shown by the TUNEL assay and an increase in caspase 3/7 activity. Both TSA and VPA were shown to cause an increase in general levels of protein acetylation in schistosomes; more particularly of histone 4 whereas histone 3 acetylation was less affected. In the case of TSA treatment this histone hyperacetylation was correlated with the increased expression of caspases 3 and 7 transcripts. Finally, quantitative chromatin immunoprecipitation showed that the proximal promoter region of the S. mansoni caspase 7 gene was hyperacetylated on histone H4 after TSA treatment.

Fc(epsilon)RI and FcgammaRIII/CD16 differentially regulate atopic dermatitis in mice

The high-affinity IgE receptor Fc(epsilon)RI and, in some models, the low-affinity IgG receptor Fc(epsilon)RIIII/CD16 play an essential role in allergic diseases. In human skin, they are present on APCs and effector cells recruited into the inflamed dermis. FcRgamma is a subunit shared, among other FcRs, by Fc(epsilon)RI and CD16 and is essential to their assembly and signal transduction. Using an experimental model reproducing some features of human atopic dermatitis and specific FcR-deficient mice, we have herein delineated the respective contribution of Fc(epsilon)RIand Fc(epsilon)RIII/CD16 to the pathology. We demonstrate that symptoms of atopic dermatitis are completely absent in FcRgamma-deficient animals but only partially inhibited in either Fc(epsilon)RI- or FcgammaRIII/CD16-deficient animals. Absence or attenuation of the pathology is correlated to increased skin expression of regulatory IL-10 and Foxp3. While Fc(epsilon)RI controls both Th1 and Th2 skin response, mast cell recruitment into draining lymph nodes and IgE production, CD16 regulates only Th2 skin response, as well as T cell proliferation and IgG1 production. This isotype-specific regulation by the cognate FcR is associated to a differential regulation of IL-4 and IL-21 expression in the draining lymph nodes. Fc(epsilon)RIand CD16 thus contribute to atopic dermatitis but differentially regulate immune responses associated with the disease. Targeting both IgE/Fc(epsilon)RI and IgG/CD16 interactions might represent an efficient therapeutic strategy for allergic diseases.

Role of marginal zone B lymphocytes in invariant NKT cell activation

Splenic marginal zone B (MZB) lymphocytes represent, along with dendritic cells (DC) a first line of defense against blood-borne pathogens. MZB cells express high levels of MHC class II and CD1d molecules but so far their ability to activate and orientate conventional and innate-like T lymphocytes, such as invariant NKT (iNKT) cells, is still elusive. In the present study, we show that murine MZB cells proliferate, mature phenotypically, and secrete cytokines in response to TLR (except TLR3) agonists. When pulsed with OVA peptide (but not whole OVA), MZB cells promote the release of IFN-gamma and IL-4 by Ag-specific CD4(+) T lymphocytes and their stimulation with the TLR9 agonist CpG oligodeoxynucleotide (ODN), a potent MZB cell activator, biases them toward more Th1 inducers. Unlike DC, CpG ODN-stimulated MZB cells fail to stimulate iNKT cells. Although able to activate iNKT hybridomas, MZB cells sensitized with free alpha-galactosylceramide (alpha-GalCer), a CD1d-restricted glycolipid Ag, do not directly activate ex vivo sorted iNKT cells unless DC are added to the culture system. Interestingly, MZB cells amplify the DC-mediated activation of iNKT cells and depletion of MZB cells from total splenocytes strongly reduces iNKT cell activation (cytokine production) in response to alpha-GalCer. Thus, DC and MZB cells provide help to each other to optimize iNKT cell stimulation. Finally, in vivo transfer of alpha-GalCer-loaded MZB cells potently activates iNKT and NK cells. This study confirms and extends the concept that MZB cells are important players in immune responses, a property that might be exploited.

[Functions of eosinophil granulocytes: from anti-parasite immunity to anti-tumoral potential]

Eosinophils have long been considered simply as effectors of adaptive immune responses during parasitic infections and inflammatory processes. Their role in allergic manifestations and mucosal responses is mediated by membrane receptors that allow them to interact with IgE and IgA antibodies. The recent demonstration that human eosinophils express innate immune receptors suggests that they may also play a role in antitumoral immune surveillance. Experimental evidence shows that human eosinophils have tumoricidal potential, in synergy with other effector cells, notably by releasing cytotoxic molecules.

Antibody response in children infected with Giardia intestinalis before and after treatment with Secnidazole

We examined 364 school children for intestinal parasites in a sub-urban zone of Caracas, Venezuela. Giardia intestinalis was the most prevalent parasite in stool samples from 34 children. Levels of IgA and IgG antibodies to G. intestinalis were assessed by enzyme-linked immunosorbent assay and Western blot before and after treatment with secnidazole. All patients were cured with a reduction of IgA antibody levels in 26 of 34 children and a reduction in IgG-specific antibody levels in 18 of 34 children. Serum of infected patients reacted with proteins of 14 kD to 137 kD. Some patients did not show a change in IgA serum reactivity for parasite proteins by Western blot after treatment. Seventeen children showed reduction of the reactivity or disappearance of protein reactivity (mainly the 14-kD, 122-kD, and 137-kD proteins). Antibody response was not related to clinical status, but quantitative and qualitative serum antibody response against G. intestinalis infection could be used to assess levels of new protein markers that decrease or disappear with successful chemotherapy.

AllergoOncology: the role of IgE-mediated allergy in cancer

Epidemiological studies have suggested inverse associations between allergic diseases and malignancies. As a proof of concept for the capability of immunoglobulin E (IgE) to destruct tumor cells, several experimental strategies have evolved to specifically target this antibody class towards relevant tumor antigens. It could be demonstrated that IgE antibodies specific to overexpressed tumor antigens have been superior to any other immunoglobulin class with respect to antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP) reactions. In an alternative approach, IgE nonspecifically attached to tumor cells proved to be a powerful adjuvant establishing tumor-specific immune memory. Active Th2 immunity could also be achieved by applying an oral immunization regimen using mimotopes, i.e. epitope mimics of tumor antigens. The induced IgE antibodies could be cross-linked by live tumor cells leading to tumoricidic mediator release. Thus, IgE antibodies may not only act in natural tumor surveillance, but could possibly also be exploited for tumor control in active and passive immunotherapy settings. Thereby, eosinophils, mast cells and macrophages can be armed with the cytophilic IgE and become potent anti-tumor effectors, able to trace viable tumor cells in the tissues. It is strongly suggested that the evolving new field AllergoOncology will give new insights into the role of IgE-mediated allergy in malignancies, possibly opening new avenues for tumor therapy.