The cytosolic tryparedoxin peroxidase from Trypanosoma cruzi induces a pro-inflammatory Th1 immune response in a peroxidatic cysteine-dependent manner

Trypanosoma cruzi cytosolic tryparedoxin peroxidase (c-TXNPx) is a 2-Cys peroxiredoxin (Prx) with an important role in detoxifying host cell oxidative molecules during parasite infection. c-TXNPx is a virulence factor, as its overexpression enhances parasite infectivity and resistance to exogenous oxidation. As Prxs from other organisms possess immunomodulatory properties, we studied the effects of c-TXNPx in the immune response and analysed whether the presence of the peroxidatic cysteine is necessary to mediate these properties. To this end, we used a recombinant c-TXNPx and a mutant version (c-TXNPxC52S) lacking the peroxidatic cysteine. We first analysed the oligomerization profile, oxidation state and peroxidase activity of both proteins by gel filtration, Western blot and enzymatic assay, respectively. To investigate their immunological properties, we analysed the phenotype and functional activity of macrophage and dendritic cells and the T-cell response by flow cytometry after injection into mice. Our results show that c-TXNPx, but not c-TXNPxC52S, induces the recruitment of IL-12/23p40-producing innate antigen-presenting cells and promotes a strong specific Th1 immune response. Finally, we studied the cellular and humoral immune response developed in the context of parasite natural infection and found that only wild-type c-TXNPx induces proliferation and high levels of IFN-γ secretion in PBMC from chronic patients without demonstrable cardiac manifestations. In conclusion, we demonstrate that c-TXNPx possesses pro-inflammatory properties that depend on the presence of peroxidatic cysteine that is essential for peroxidase activity and quaternary structure of the protein and could contribute to rational design of immune-based strategies against Chagas disease.

Increase in Autoantibodies-Abzymes with Peroxidase and Oxidoreductase Activities in Experimental Autoimmune Encephalomyelitis Mice during the Development of EAE Pathology

The exact mechanisms of multiple sclerosis (MS) development are still unknown, but the development of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice is associated with the violation of bone marrow hematopoietic stem cells (HSCs) differentiation profiles associated with the production of harmful for human’s autoantibodies hydrolyzing myelin basic protein, myelin oligodendrocyte glycoprotein (MOG_35–55), and DNA. It was shown that IgGs from the sera of healthy humans and autoimmune patients oxidize many different compounds due to their H₂O₂-dependent peroxidase and oxidoreductase activity in the absence of H₂O₂. Here we first analyzed the change in the relative redox activities of IgGs antibodies from the blood of C57BL/6 mice over time at different stages of the EAE development. It was shown that the peroxidase activity of mice IgGs in the oxidation of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) is on average 6.9-fold higher than the oxidoreductase activity. The peroxidase activity of IgGs increased during the spontaneous development of EAE during 40 days, 1.4-fold. After EAE development acceleration due to mice immunization with MOG_35–55 (5.3-fold), complexes of bovine DNA with methylated bovine serum albumin (DNA-metBSA; 3.5-fold), or with histones (2.6-fold), the activity was increased much faster. The increase in peroxidase activity after mice immunization with MOG_35–55 and DNA-metBSA up to 40 days of experiments was relatively gradual, while for DNA-histones complex was observed its sharp increase at the acute phase of EAE (14–20 days). All data show that IgGs’ redox activities can play an important role in the protection of mice from toxic compounds and oxidative stress.

Inhibitory Anti-Peroxidasin Antibodies in Pulmonary-Renal Syndromes

BACKGROUND

Goodpasture syndrome (GP) is a pulmonary-renal syndrome characterized by autoantibodies directed against the NC1 domains of collagen IV in the glomerular and alveolar basement membranes. Exposure of the cryptic epitope is thought to occur via disruption of sulfilimine crosslinks in the NC1 domain that are formed by peroxidasin-dependent production of hypobromous acid. Peroxidasin, a heme peroxidase, has significant structural overlap with myeloperoxidase (MPO), and MPO-ANCA is present both before and at GP diagnosis in some patients. We determined whether autoantibodies directed against peroxidasin are also detected in GP.

METHODS

We used ELISA and competitive binding assays to assess the presence and specificity of autoantibodies in serum from patients with GP and healthy controls. Peroxidasin activity was fluorometrically measured in the presence of partially purified IgG from patients or controls. Clinical disease severity was gauged by Birmingham Vasculitis Activity Score.

RESULTS

We detected anti-peroxidasin autoantibodies in the serum of patients with GP before and at clinical presentation. Enriched anti-peroxidasin antibodies inhibited peroxidasin-mediated hypobromous acid production in vitro. The anti-peroxidasin antibodies recognized peroxidasin but not soluble MPO. However, these antibodies did crossreact with MPO coated on the polystyrene plates used for ELISAs. Finally, peroxidasin-specific antibodies were also found in serum from patients with anti-MPO vasculitis and were associated with significantly more active clinical disease.

CONCLUSIONS

Anti-peroxidasin antibodies, which would previously have been mischaracterized, are associated with pulmonary-renal syndromes, both before and during active disease, and may be involved in disease activity and pathogenesis in some patients.

Serum Helicobacter pylori KatA and AhpC antibodies as novel biomarkers for gastric cancer

AIM: To investigate catalase (KatA) and alkyl hydroperoxide reductase (AhpC) antibodies of Helicobacter pylori as biomarkers for gastric cancer (GC).

METHODS: This study included 232 cases and 264 controls. Recombinant KatA and AhpC proteins were constructed and the levels of antibodies were tested by indirect enzyme-linked immunosorbent assay (ELISA). Logistic regression was applied to analyze the relationships between KatA, AhpC and GC. The χ² trend test was used to evaluate the dose-response relationships between serum KatA and AhpC antibody levels and GC. Receiver operating characteristic (ROC) curve was used to evaluate the screening accuracy of KatA and AhpC as biomarkers. Combined analysis was used to observe screening accuracy of predictors for GC.

RESULTS: In all subjects, the association between KatA and AhpC and GC risk was significant (P < 0.001) with odds ratio (OR) = 12.84 (95%CI: 7.79-21.15) and OR = 2.4 (95%CI: 1.55-3.73), respectively. KatA and AhpC antibody levels were strongly related to GC risk with a dose-dependent effect (P for trend < 0.001). The area under the ROC (AUC) for KatA was 0.806, providing a sensitivity of 66.81% and specificity of 86.36%; and the AUC for AhpC was 0.615, with a sensitivity of 75.65% and specificity of 45.49%. The AUC was 0.906 for KatA and flagella protein A (FlaA) combined analysis.

CONCLUSION: Serum KatA and AhpC antibodies are associated with GC risk and KatA may serve as a biomarker for GC. KatA/FlaA combined analysis improved screening accuracy.

Differential innate immune response of European seabass (Dicentrarchus labrax) against Streptococcus iniae

Streptococcus iniae is a Gram-positive bacteria that causes invasive infections with severe septicemia and meningitis, producing high economic losses in marine and continental aquaculture. Head kidney leukocytes of European sea bass (Dicentrarchus labrax) were used to measure the differential innate immune response upon infection with S. iniae. The complete inhibition in the production of intracellular superoxide radicals and total peroxidase content was observed in infected cells. This study also elucidates changes in the relative expression of some immune-related genes. Interleukin 1β, tumor necrosis factor-α and interleukin-6 reached a peak of expression at 4-8 h post-infection, subsequently decreasing significantly up to 48 h post-infection. However, interleukin-10 and Mx protein increased over time, reaching the pick of expression at 48 h post-infection, whereas caspase-3 showed down regulation until 48 h post-infection. The in vivo study of immune related genes show the same kinetics of mRNAs expression as in vitro experience. The proinflammatory cytokines mRNA transcription levels peaked at an earlier time in vivo than in vitro system. Our findings indicate that there is a direct relationship between the dissemination of bacteria and the resulting infection-associated inhibition of respiratory burst, apoptosis, and the pro- and anti-inflammatory gene expression profiles.

[Effect of chitooligosaccharides with different degrees of acetylation on the activity of wheat pathogen-inducible anionic peroxidase]

The effect of chitooligosaccharides (CHOSs) with a molecular weight of 5-10 kDa and a degree of acetylation (DA) of 65 and 13% at a concentration of 1.0 mg/L on the expression of the TC151917 gene, which encodes wheat anionic peroxidase, and the activity of "anionic" isoperoxidases in common wheat plants infected with Septoria nodorum Berk.--the causative agent of septoriosis. Treatment with CHOSs with a 65% DA and infection promoted the transcription of the anionic peroxidase gene and increased the enzymatic activity of the anionic peroxidase with an isoelectric point of 3.5 in soluble and ion-bound to cell walls protein fractions. Chitooligosaccharides with a 13% DA change these parameters to a lesser extent. These data suggest the importance of the degree of acetylation of CHOSs in the development of immune responses of wheat with the involvement of peroxidases.

Leishmania amazonensis amastigotes highly express a tryparedoxin peroxidase isoform that increases parasite resistance to macrophage antimicrobial defenses and fosters parasite virulence

Professional phagocytes generate a myriad of antimicrobial molecules to kill invading microorganisms, of which nitrogen oxides are integral in controlling the obligate intracellular pathogen Leishmania. Although reactive nitrogen species produced by the inducible nitric oxide synthase (iNOS) can promote the clearance of intracellular parasites, some Leishmania species/stages are relatively resistant to iNOS-mediated antimicrobial activity. The underlying mechanism for this resistance remains largely uncharacterized. Here, we show that the amastigote form of L. amazonensis is hyper-resistant to the antimicrobial actions of cytokine-activated murine and human macrophages as compared to its promastigote counterpart. Amastigotes exhibit a marked ability to directly counter the cytotoxicity of peroxynitrite (ONOO⁻), a leishmanicidal oxidant that is generated during infection through the combined enzymatic activities of NADPH oxidase and iNOS. The enhanced antinitrosative defense of amastigotes correlates with the increased expression of a tryparedoxin peroxidase (TXNPx) isoform that is also upregulated in response to iNOS enzymatic activity within infected macrophages. Accordingly, ectopic over-expression of the TXNPx isoform by L. amazonensis promastigotes significantly enhances parasite resistance against ONOO⁻ cytotoxicity. Moreover, TXNPx-overexpressing parasites exhibit greater intra-macrophage survival, and increased parasite growth and lesion development in a murine model of leishmaniasis. Our investigations indicate that TXNPx isoforms contribute to Leishmania's ability to adapt to and antagonize the hostile microenvironment of cytokine-activated macrophages, and provide a mechanistic explanation for persistent infection in experimental and human leishmaniasis.

Pathogens of the genus Leishmania are the causative agents of leishmaniasis, a neglected tropical disease responsible for significant morbidity and mortality worldwide. Although it is well accepted that host-derived leishmanicidal molecules mediate resolution of Leishmania infection, some Leishmania species/stages are relatively resistant to host cell antimicrobial activity. These intracellular pathogens have developed evasive strategies to subvert host antimicrobials, and promote pathogen survival within the harsh intracellular environment. However, the underlying mechanisms remain largely uncharacterized. Here, we show that L. amazonensis, an agent of persistent infection in humans and non-healing skin lesions in mice, antagonize macrophage antimicrobial activity. The superb ability of the amastigote form to survive within host cells is related to its increased expression of a tryparedoxin peroxidase isoform that confers resistance to the cytotoxicity of host-derived antimicrobial molecules. Parasites induce higher expression of the TXNPx in response to iNOS activity during infection of macrophages, indicating that parasites can “sense” the microenvironment of host cells and regulate the expression of relevant virulence factors accordingly. Our investigations are consistent with a model by which Leishmania amastigotes utilize TXNPx to defend against host-derived molecules thereby promoting their intracellular survival and persistent infection.

Autoantibodies to Peroxiredoxin I and IV in Patients with Systemic Autoimmune Diseases

Anti-oxidative enzymes protect living bodies from various oxidative stresses. In the systemic autoimmune diseases, autoantibodies to oxidized molecules and to anti-oxidative enzymes have been reported. To promote understanding of the relationships between autoimmunity and oxidative stress, we here investigate whether autoimmunity to the anti-oxidative peroxiredoxin (Prxs) enzymes exists in patients with systemic autoimmune diseases. Specifically, we detected autoantibodies to recombinant Prx I and Prx IV respectively by ELISA and western blotting. Next, clinical parameters were compared between the anti-Prx I or IV-positive and-negative patients. We found that 33% of the 92 patients with autoimmune diseases tested possessed autoantibodies to Prx I (57% in systemic lupus erythematosus (SLE), 19% in rheumatoid arthritis (RA), 5% in Behçet disease, and 46% in primary vasculitis syndrome). In contrast, autoantibodies to Prx IV were detected in only 17% of the same patients. No significant correlation was found between occurrence of the two autoantibodies. Clinically, possession of anti-Prx I autoantibodies correlated with lower serum levels of CH50, C3, and C4. Taken together, our data demonstrate the existence of autoantibodies to Prxs for the first time. The autoantibodies to Prx I may be involved in the pathophysiology of systemic autoimmune diseases such as SLE and vasculitis.

Ciona intestinalis peroxinectin is a novel component of the peroxidase-cyclooxygenase gene superfamily upregulated by LPS

Peroxinectins function as hemoperoxidase and cell adhesion factor involved in invertebrate immune reaction. In this study, the ascidian (Ciona intestinalis) peroxinectin gene (CiPxt) and its expression during the inflammatory response have been examined. CiPxt is a new member of the peroxidase-cyclooxygenase gene superfamily that contains both the peroxidase domain and the integrin KGD (Lys-Gly-Asp) binding motif. A phylogenetic tree showed that CiPxt is very close to the chordate group and appears to be the outgroup of mammalian MPO, EPO and TPO clades. The CiPxt molecular structure model resulted superimposable to the human myeloperoxidase. The CiPxt mRNA expression is upregulated by LPS inoculation suggesting it is involved in C. intestinalis inflammatory response. The CiPxt was expressed in hemocytes (compartment/morula cells), vessel epithelium, and unilocular refractile granulocytes populating the inflamed tunic matrix and in the zones 7, 8 and 9 of the endostyle, a special pharynx organs homolog to the vertebrate thyroid gland.

Influence of melatonin on the immune system of fish: a review

Endocrine-immune system interactions have been widely demonstrated in mammals, whereas in fish, these relationships remain unclear. Of the organs that constitute the endocrine system, the pineal gland and its secretory product melatonin act in the synchronization of daily and seasonal rhythms in most vertebrates, including fish. Seasonal differences in immunocompetence and disease prevalence have been well documented in humans. Seasonality also strongly influences the life history of fish by controlling the timing of physiological events, such as reproduction, food intake, locomotor activity, and growth performance. Apart from its synchronizing capabilities, the role of melatonin in physiological processes in fish is not thoroughly understood. The purpose of this review is to summarize current studies on the effects of melatonin on the fish immune system. These studies suggest that melatonin represents an important component of fish endocrine-immune system interactions. The elucidation of the defense mechanisms of fish will facilitate the development of health management tools to support the growing finfish aquaculture industry as well as address questions concerning the origins and evolution of the immune system in vertebrates.

Pituitary antibodies in women with Hashimoto's thyroiditis: prevalence in diagnostic and prediagnostic sera

BACKGROUND

Pituitary antibodies have been reported with greater frequency in patients with Hashimoto's thyroiditis than in healthy controls, although there is significant variability in the strength of the association and the methodologies used.

METHODS

We designed a nested case-control study to characterize the prevalence of pituitary antibodies at the time of the clinical diagnosis of Hashimoto's thyroiditis, as well as at 2, 5, and 7 years before diagnosis. Active component female service member cases (n=87) and matched female controls (n=107) were selected using the Defense Medical Surveillance System database (DMSSD) between January 1998 and December 2007. Pituitary antibodies were measured by immunofluorescence using human pituitary glands collected at autopsy as the substrate.

RESULTS

At diagnosis, pituitary antibodies were present in 9% of cases with Hashimoto's (8 of 87) and 3% of controls (3 of 107). When the data were analyzed using a conditional logistic regression model, which takes into account the matching on age and work status, pituitary antibodies increased the odds of having Hashimoto's thyroiditis by sevenfold (95% confidence interval from 1.3 to 40.1, p=0.028), after adjusting for components of the DMSSD-category-termed race and for thyroperoxidase antibodies. Before diagnosis, pituitary antibodies were positive in 3 of the 11 subjects (2 cases and 1 control) at the -2-year time point, and negative in all 11 subjects at the -5- and -7-year time points.

CONCLUSIONS

In summary, using a nested case-control design, we confirm that pituitary antibodies are more common in Hashimoto's thyroiditis and suggest that they appear late during its natural history.

A prime/boost DNA/Modified vaccinia virus Ankara vaccine expressing recombinant Leishmania DNA encoding TRYP is safe and immunogenic in outbred dogs, the reservoir of zoonotic visceral leishmaniasis

Previous studies demonstrated safety, immunogenicity and efficacy of DNA/modified vaccinia virus Ankara (MVA) prime/boost vaccines expressing tryparedoxin peroxidase (TRYP) and Leishmania homologue of the mammalian receptor for activated C kinase (LACK) against Leishmania major challenge in mice, which was consistent with results from TRYP protein/adjuvant combinations in non-human primates. This study aimed to conduct safety and immunogenicity trials of these DNA/MVA vaccines in dogs, the natural reservoir host of Leishmania infantum, followed-up for 4 months post-vaccination. In a cohort of 22 uninfected outbred dogs, blinded randomised administration of 1000 microg (high dose) or 100 microg (low dose) DNA prime (day 0) and 1x10(8)pfu MVA boost (day 28) was shown to be safe and showed no clinical side effects. High dose DNA/MVA vaccinated TRYP dogs produced statistically higher mean levels of the type-1 pro-inflammatory cytokine IFN-gamma than controls in whole blood assays (WBA) stimulated with the recombinant vaccine antigen TRYP, up to the final sampling at day 126, and in the absence of challenge with Leishmania. TRYP vaccinated dogs also demonstrated significantly higher TRYP-specific total IgG and IgG2 subtype titres than in controls, and positive in vivo intradermal reactions at day 156 in the absence of natural infection, observed in 6/8 TRYP vaccinated dogs. No significant increases in IFN-gamma in LACK-stimulated WBA, or in LACK-specific IgG levels, were detected in LACK vaccinated dogs compared to controls, and only 2/9 LACK vaccinated dogs demonstrated DTH responses at day 156. In all groups, IgG1 subclass responses and antigen-specific stimulation of IL-10 were similar to controls demonstrating an absence of Th2/T(reg) response, as expected in the absence of in vivo restimulation or natural/experimental challenge with Leishmania. These collective results indicate significant antigen-specific type-1 responses and in vivo memory phase cellular immune responses, consistent with superior potential for protective vaccine immunogenicity of DNA/MVA TRYP over LACK.

Identification and characterization of VPO1, a new animal heme-containing peroxidase

Animal heme-containing peroxidases play roles in innate immunity, hormone biosynthesis, and the pathogenesis of inflammatory diseases. Using the peroxidase-like domain of Duox1 as a query, we carried out homology searching of the National Center for Biotechnology Information database. Two novel heme-containing peroxidases were identified in humans and mice. One, termed VPO1 for vascular peroxidase 1, exhibits its highest tissue expression in heart and vascular wall. A second, VPO2, present in humans but not in mice, is 63% identical to VPO1 and is highly expressed in heart. The peroxidase homology region of VPO1 shows 42% identity to myeloperoxidase and 57% identity to the insect peroxidase peroxidasin. A molecular model of the VPO1 peroxidase region reveals a structure very similar to that of known peroxidases, including a conserved heme binding cavity, critical catalytic residues, and a calcium binding site. The absorbance spectra of VPO1 are similar to those of lactoperoxidase, and covalent attachment of the heme to VPO1 protein was demonstrated by chemiluminescent heme staining. VPO1 purified from heart or expressed in HEK cells is catalytically active, with a K(m) for H(2)O(2) of 1.5 mM. When co-expressed in cells, VPO1 can use H(2)O(2) produced by NADPH oxidase enzymes. VPO1 is likely to carry out peroxidative reactions previously attributed exclusively to myeloperoxidase in the vascular system.

Preparation of antibody against horseradish peroxidase using hybridoma technology

BACKGROUND

Monoclonal antibody against horseradish peroxidase (HRP) has many applications which peroxidase anti-peroxidase. Peroxidase-antiperoxidase (PAP) complex formation is its most known and important usage. This complex is used in many immunohistochemical and immunocytochemical staining techniques.

OBJECTIVE

The aim of this study was the preparation of anti-HRP monoclonal antibody through hybridoma technology.

METHODS

The BALB/c mice were immunized by repeated injections of HRP. After the confirmation of their immunization by ELISA test, the spleen lymphocytes and SP2/0 myeloma cells were hybridized using PEG as fusing agent. The hybridoma cells were then selected by culturing in HAT medium. Identification and selection of anti-HRP producing clones were done by ELISA test on culture supernatants of the obtained clones. To acquire the monoclones, limiting dilution was performed twice and the effect of finally obtained antibodies on enzyme activity was investigated by a specific ELISA test. In vivo tumor induction method was used for production of concentrated antibody. At last class and subclass of the obtained antibodies were determined by Isostrip Kit.

RESULTS

After seven rounds of cell fusions, 224 clones were obtained, from which, six ones were anti-HRP producers. Two clones (P1F11 and P2F6) with higher antibody secretion were selected and subcloned. Both derived hybridoma monoclones (P1F11D2 and P2F6F3) were producing antibodies from IgG1 subclass with kappa (Kappa) light chains which didn't affect the enzyme activity. The electrophoresis of ascetic fluid of tumor induced mice showed an obvious band in gamma (gamma) position.

CONCLUSION

The obtained monoclonal antibodies are from IgG class and don't affect the enzyme activity, therefore it seems that they are suitable for PAP complex production.

Multiple Mycobacterium antigens induce interferon-gamma production from sarcoidosis peripheral blood mononuclear cells

Studies of sarcoidosis immunology have noted oligoclonal T cell populations, suggesting cell-mediated immunity that is antigen-specific. Sarcoidosis immunology and pathology are most similar to mycobacterial infections. Mycobacterium tuberculosis infection in mice and humans reflects T helper 1 (Th1) immune responses to multiple cell wall and secreted antigens. We investigated if the oligoclonal immune response in individual sarcoidosis subjects could be elicited by multiple secreted mycobacterial antigens by performing ex vivo enzyme-linked immunospot assay (ELISPOT) on peripheral blood mononuclear cells (PBMC) from 30 sarcoidosis, 26 purified protein derivative negative (PPD-) control and 10 latent tuberculosis subjects (PPD+) to assess Th1 responses to mycobacterial superoxide dismutase A (sodA), catalase-peroxidase (katG) and early secreted antigenic target protein (ESAT-6). A significant difference was noted among the sarcoidosis and PPD- control subjects to ESAT-6 [12 of 30 versus one of 26 (P = 0.0014)], katG [nine of 30 versus none of 26 (P = 0.002)] and sodA [12 of 30 versus none of 26 (P = 0.002)]. There was no significant difference between sarcoidosis and PPD+ subjects. Twelve sarcoidosis subjects recognized two or more mycobacterial proteins, as well as multiple distinct epitopes within individual proteins. One sarcoidosis subject on whom we collected bronchoalveolar lavage (BAL) fluid and PBMC had no recognition of mycobacterial antigens using PBMC, but BAL fluid demonstrated strong Th1 immune responses to ESAT-6 and katG. Individual sarcoidosis subjects recognized not only multiple mycobacterial proteins, but multiple distinct peptides within a specific protein, thus demonstrating that multiple mycobacterial epitopes elicit the Th1 immune response observed. Immune responses by sarcoidosis T cells to mycobacterial proteins may have an important role in sarcoidosis pathogenesis.

Leish-111f, a recombinant polyprotein vaccine that protects against visceral Leishmaniasis by elicitation of CD4+ T cells

The Leishmania-derived recombinant polyprotein Leish-111f or its three component proteins, thiol-specific antioxidant (TSA), Leishmania major stress-inducible protein 1 (LmSTI1), and Leishmania elongation initiation factor (LeIF), have previously been demonstrated to be efficacious against cutaneous or mucosal leishmaniasis in mice, nonhuman primates, and humans. In this study we demonstrate that Leish-111f is also a vaccine antigen candidate against visceral leishmaniasis (VL) caused by Leishmania infantum. We evaluated the immune response and protection induced by Leish-111f formulated with monophosphoryl lipid A in a stable emulsion (Leish-111f+MPL-SE) and demonstrated that mice developed strong humoral and T-cell responses to the vaccine antigen. Analysis of the cellular immune responses of immunized, uninfected mice demonstrated that the vaccine induced a significant increase in CD4(+) T cells producing gamma interferon, interleukin 2, and tumor necrosis factor cytokines, indicating a Th1-type immune response. Experimental infection of immunized mice and hamsters demonstrated that Leish-111f+MPL-SE induced significant protection against L. infantum infection, with reductions in parasite loads of 99.6%, a level of protection greater than that reported for other vaccine candidates in animal models of VL. Taken together, our results suggest that this vaccine represents a good candidate for use against several Leishmania species. The Leish-111f+MPL-SE product we report here is the first defined vaccine for leishmaniasis in human clinical trials and has completed phase 1 and 2 safety and immunogenicity testing in normal, healthy human subjects.

Autoantibody against peroxiredoxin I, an antioxidant enzyme, in patients with systemic sclerosis: possible association with oxidative stress

OBJECTIVES

To determine the prevalence and clinical correlation of autoantibody to peroxiredoxin (Prx) I, an antioxidant enzyme, in patients with systemic sclerosis (SSc).

METHODS

Serum samples from SSc patients (n = 70) and healthy controls (n = 23) were examined by ELISA using human recombinant Prx I. The presence of anti-Prx I antibody was further evaluated by immunoblotting analysis. To determine the functional relevance of anti-Prx I antibody in vivo, we assessed whether anti-Prx I antibody was able to inhibit Prx I enzymatic activity using yeast thioredoxin reductase system.

RESULTS

IgG anti-Prx I antibody levels in SSc patients were significantly higher than healthy controls and this autoantibody was detected in 33% of SSc patients. The presence of IgG anti-Prx I antibody was associated with longer disease duration, more frequent presence of pulmonary fibrosis, heart involvement, and anti-topoisomerase I antibody and increased levels of serum immunoglobulin and erythrocyte sedimentation rates. IgG anti-Prx I antibody levels also correlated positively with renal vascular damage and negatively with pulmonary function tests. Furthermore, anti-Prx I antibody levels correlated positively with serum levels of 8-isoprostane, a marker of oxidative stress. Immunoblotting analysis confirmed the presence of anti-Prx I antibody. Remarkably, Prx I enzymatic activity was inhibited by IgG isolated from SSc sera containing IgG anti-Prx I antibody.

CONCLUSIONS

These results suggest that elevated IgG anti-Prx I autoantibody is associated with the disease severity of SSc and that anti-PrxI antibody may enhance the oxidative stress by inhibiting Prx I enzymatic activity.

Vasculitis induced by immunization with Bacillus Calmette-Guérin followed by atypical mycobacterium antigen: a new mouse model for Kawasaki disease

Kawasaki disease causes systemic vasculitis. The development of skin lesions at the vaccination site with Bacillus Calmette-Guérin (BCG) is an important diagnostic symptom. We hypothesized that infection with ubiquitous microorganisms immunogenically related to BCG might induce an immunopathologic reaction leading to the development of Kawasaki disease. Mice were first inoculated with BCG, and then secondarily inoculated 4 weeks later with crude extract from Mycobacterium intracellulare (cMI), an abundant atypical mycobacterium. Animals inoculated with BCG followed by cMI developed coronary arteritis with infiltration of inflammatory cells, whereas control animals inoculated with only cMI or BCG did not, suggesting that the immune response to the mycobacteria induced autoimmunity to the vascular wall. Intravenous injection with antibodies to peroxiredoxin II, a modulator of vascular remodeling and a suggested target for autoimmune vasculitis, also resulted in coronary arteritis, but only after prior inoculation with BCG. Tumor necrosis factor-alpha, MCP1 and interferon-gamma production were significantly higher in the animals inoculated with BCG than in the control groups (P<0.05). BCG immunization was required for the development of coronary arteritis, suggesting that these cytokines might play important roles. The results indicate that BCG induces primary autoimmunity and stimulates cytokine induction, and that atypical mycobacterial infection boosts the autoimmunity resulting in coronary arteritis.

Proteomics-based approach identifying autoantibody against peroxiredoxin VI as a novel serum marker in esophageal squamous cell carcinoma

PURPOSE

Detection of novel tumor-related antigens and autoantibodies will aid in diagnosis of early-stage cancer and in development of more effective immunotherapies. The purpose of this study was to identify novel tumor antigens in an esophageal squamous cell carcinoma (ESCC) cell line (TE-2) and related autoantibodies in sera from patients with ESCC using a proteomics-based approach.

EXPERIMENTAL DESIGN

TE-2 proteins were separated by two-dimensional PAGE, followed by Western blot analysis in which sera of patients with ESCC, healthy controls, and patients with other cancers were tested for primary antibodies. Positive spots were excised from silver-stained gels and analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS).

RESULTS

Sera from patients with ESCC yielded multiple spots, one of which was identified as peroxiredoxin (Prx) VI by MALDI-TOF/TOF MS. Western blot analysis against recombinant Prx VI showed reactivity in sera from 15 of 30 (50%) patients with ESCC and 2 of 30 (6.6%) healthy individuals. Autoantibody against Prx VI was found in sera from 1 of 30 (3.3%) patients with other types of cancer (colon cancer).

CONCLUSION

We have identified for the first time an autoantibody against Prx VI in ESCC patients. The proteomic approach implemented here offers a powerful tool for identifying novel serum markers that may display clinical usefulness against cancer.

Heterologous priming-boosting with DNA and modified vaccinia virus Ankara expressing tryparedoxin peroxidase promotes long-term memory against Leishmania major in susceptible BALB/c Mice

Leishmaniasis affects 12 million people, but there are no vaccines in routine clinical use. Th1 polarizing vaccines that elicit long-term protection are required to prevent disease in susceptible populations. We recently showed that heterologous priming-boosting with tryparedoxin peroxidase (TRYP) DNA followed by TRYP-modified vaccinia virus Ankara (TRYP MVA) protected susceptible BALB/c mice from Leishmania major. Here we compared treatment with TRYP DNA with treatment with TRYP DNA/TRYP MVA. We found that equivalent levels of protection during the postvaccination effector phase correlated with equivalent levels of serum immunoglobulin G2a and gamma interferon (IFN-gamma) in draining lymph nodes. In contrast, challenge infection during the memory phase revealed that there was enhanced clinical efficacy with TRYP DNA/TRYP MVA. This correlated with higher levels of effector phase splenic IFN-gamma, sustained prechallenge levels of memory phase IFN-gamma, and a more polarized post-L. major challenge Th1 response compared to the Th2/T(reg) response. Thus, TRYP DNA/TRYP MVA, but not TRYP DNA alone, provides long-term protection against murine leishmaniasis.

MOLECULAR CLONING AND CHARACTERIZATION OF A 2-CYS PEROXIREDOXIN FROM TAENIA SOLIUM

A Taenia solium 2-Cys peroxiredoxin (Ts2-CysPrx) clone was isolated from a T. solium adult cDNA library. The clone encodes a polypeptide comprising 197 amino acids with a predictive Mr = 21,836. It has the 2 classical cysteine domains from the typical 2-Cys peroxiredoxins, and its primary amino acid sequence shows higher identity with 2 Echinococcus 2-Cys peroxiredoxins. Northern and Southern blot hybridizations exhibit an mRNA with a size of -1.0 kb, encoded by 1 gene. Ts2-CysPrx was expressed in Escherichia coli and purified by anion-exchange chromatography. Biochemical analysis showed Ts2-CysPrx is a dimer composed by monomers of -22 kDa that presented activity with hydrogen peroxide (H2O2) and cumene hydroperoxide. It presented the catalytic mechanism for a typical 2-CysPrx because the homodimeric oxidized form is reduced to a monomeric form by thioredoxin (Trx) and by dithiothreitol (DTT) and was converted to a homodimeric oxidized form by H2O2. Western blot studies using antibodies against Ts2-CysPrx revealed that the protein is expressed during the entire T. solium life cycle, as in other Taenia species. Immunohistochemical studies indicated that Ts2-CysPrx is localized on the tegument and in tegumentary and muscle cells of cysticerci. We also show that T. crassiceps cysticerci can tolerate H2O2 levels of 2.5 mM for 2.5 hr.

The current status of an amebiasis vaccine

Efficient control of infectious diseases requires the development and application of suitable vaccines. Development of vaccines against amebiasis is still in its infancy. However, in recent years progress has been made in the identification of possible vaccine candidates, the route of application and the understanding of the immune response that is required for protection against amebiasis.

IL-10 from Regulatory T Cells Determines Vaccine Efficacy in MurineLeishmania majorInfection

Leishmaniasis affects 12 million people, but there are no vaccines. Immunological correlates of vaccine efficacy are unclear. Polarized Th1 vs Th2 responses in Leishmania major-infected mice suggested that a shift in balance from IL-4 to IFN-gamma was the key to vaccine success. Recently, a role for IL-10 and regulatory T cells in parasite persistence was demonstrated, prompting re-evaluation of vaccine-induced immunity. We compared DNA/modified vaccinia virus Ankara heterologous prime-boost with Leishmania homolog of the receptor for activated C kinase (LACK) or tryparedoxin peroxidase (TRYP). Both induced low IL-4 and high IFN-gamma prechallenge. Strikingly, high prechallenge CD4 T cell-derived IL-10 predicted vaccine failure using LACK, whereas low IL-10 predicted protection with TRYP. The ratio of IFN-gamma:IL-10 was thus a clear prechallenge indicator of vaccine success. Challenge infection caused further polarization to high IL-10/low IFN-gamma with LACK and low IL-10/high IFN-gamma with TRYP. Ex vivo quantitative RT-PCR and in vitro depletion and suppression experiments demonstrated that Ag-driven CD4+ CD25+ T regulatory 1-like cells were the primary source of IL-10 in LACK-vaccinated mice. Anti-IL-10R treatment in vivo demonstrated that IL-10 was functional in determining vaccine failure, rendering LACK protective in the presence of high IFN-gamma/low IL-5 responses.

Peroxiredoxin-I is an autoimmunogenic tumor antigen in non-small cell lung cancer

In eukaryotic cells, peroxiredoxins are both antioxidants and regulators of H(2)O(2)-mediated signaling. We previously found that peroxiredoxin-I (Prx-I) was overexpressed in non-small cell lung cancer (NSCLC) tissue. Since overexpressed protein can induce a humoral immune response, we examined whether serum from NSCLC patients exhibited immunoreactivity against Prx-I using Western blotting. We found that 25 (47%) of 53 NSCLC patients tested had autoantibodies against Prx-I in their sera, whereas such activity was detected in 4 (8%) sera from 50 healthy subjects. Prx-I itself was detected in the sera from 18 (34%) of 53 NSCLC patients but in only 1 (2%) serum from 50 controls. Moreover, 17% of NSCLC sera were positive to both Prx-I antibody and antigen but none in control sera. The data indicate both Prx-I autoantibody and circulating antigen are potential biomarkers for use in serological diagnosis of NSCLC. Interestingly enough, we found that Prx-I was secreted by lung adenocarcinoma cells (A549) but not by non-cancer lung cells (BEAS 2B) or breast cancer cells (MCF7). This cell culture study suggests the possibility of Prx-I secretion from NSCLC tumor tissues.

Expression of a peroxiredoxin-glutaredoxin by Haemophilus influenzae in biofilms and during human respiratory tract infection

Evidence is mounting that nontypeable Haemophilus influenzae grows as a biofilm in the middle ear of children with otitis media and the airways of adults with chronic obstructive pulmonary disease. To begin to assess antigens expressed by H. influenzae in biofilms, cell envelopes of bacteria grown as a biofilm were compared to those grown planktonically. A approximately 30kDa peroxiredoxin-glutaredoxin was present in greater abundance during growth in biofilms. Mutants deficient in expression of peroxiredoxin-glutaredoxin were constructed by homologous recombination in four clinical isolates. The mutants showed a 25-50% reduction in biofilm formation compared to the corresponding parent strains. To study in vivo expression of peroxiredoxin-glutaredoxin during human respiratory tract infection, paired pre- and post-exacerbation serum from adults with chronic obstructive pulmonary disease and H. influenzae in sputum were assayed using an enzyme-linked immunosorbent assay and purified recombinant peroxiredoxin-glutaredoxin. Eight from 18 (44.4%) paired serum samples showed a significant increase in antibody to peroxiredoxin-glutaredoxin from pre- to post-infection. These results indicate that (1) peroxiredoxin-glutaredoxin is present in greater abundance in H. influenzae biofilms compared to planktonically grown bacteria; (2) peroxiredoxin-glutaredoxin is involved in biofilm formation by H. influenzae and the degree of involvement varies among strains; and (3) peroxiredoxin-glutaredoxin is expressed by H. influenzae during infection of the human respiratory tract and is recognized by the human immune system.

Purification and biochemical characterization of a heme containing peroxidase from the human parasite P. falciparum

A peroxidase (30 kDa) has been purified from the human malaria parasite Plasmodium falciparum to its homogeneity. The protein is a dimer of 15 kDa subunit as evident from SDS-PAGE and MALDI-TOF mass analysis. The antibodies developed against the purified protein cross-react selectively with this protein present in parasite lysate. It is a heme containing peroxidase [R/Z value (A408/A278)=2.33] showing characteristic heme spectra with Soret peak at 408 nm and visible peaks at 536 and 572 nm. Analysis of Soret spectra in presence or absence of cyanide or azide reveals that iron of heme is in Fe-III state. Circular dichroism spectral analysis establishes that this protein contains mainly alpha-helix (60-70%). H2O2 interacts with the heme moiety of the enzyme as evidenced by optical difference spectroscopy and spectral studies indicate the formation of catalytically active peroxidase-H2O2 complex (Soret peak at 413 nm) to exhibit peroxidase activity. During the erythrocytic stages of its life cycle, the parasite is exposed to oxidative stress. As the parasite is susceptible to oxidative stress, this peroxidase may offer antioxidant role by scavenging endogenous H2O2.

Prevalência de auto-imunidade tireoidiana em um grupo de pacientes com diabetes mellitus tipo 1 em Londrina, PR

A auto-imunidade tireoidiana é uma co-morbidade freqüente entre pacientes com diabetes mellitus tipo 1 (DM1). Neste estudo, avaliamos a prevalência da positividade para auto-anticorpos anti-tireoidianos (anti-microssomal, anti-Tg e anti-TPO), bem como características clínicas (idade, sexo, duração do DM) e laboratoriais (função tireoidiana, HbA1) de 101 pacientes (idade média de 20 ± 9,6 anos; 62 do sexo feminino) com DM atendidos no HC/UEL. RESULTADOS: A presença de auto-anticorpos foi detectada em 31 pacientes (30,7%). No grupo com idade <12 anos, a prevalência de anticorpos foi de 15%; entre 12-18 anos, 32%, e >18 anos, 35,7% (p= 0,22). Entre os 31 pacientes com anticorpos positivos, 40% apresentava alguma disfunção tireoidiana, comparados a apenas 4,4% daqueles sem anticorpos (p<0,001). O TSH médio foi maior no grupo com anticorpos presentes (3,75 vs. 2,32µU/mL; p= 0,01). CONCLUSÃO: A prevalência da positividade para anticorpos marcadores de tireoidite auto-imune foi de em 30,7%, compatível com a literatura.

Identification of epithelial auto-antigens associated with periodontal disease

We previously reported evidence that patients with periodontitis have serum antibodies to oral Gram positive bacteria that are cross-reactive with epithelial antigens. In the present report cross-reactive epithelial antigens including CD24, lactate dehydrogenase A [LDM-A], antioxidant protein 2 [AOP 2] and nuclear factor of activated T cells 5 [NFAT 5], were identified by screening a cDNA expression library with pooled patient sera. Titres of antibodies to CD24 peptide correlated negatively with indices of periodontal disease severity. Strong expression of CD24 in the reactive periodontal epithelium and inflamed gingival attachment contrasted with low to undetectable expression in the external gingival epithelium. In periodontitis, a local action of these auto-reactive antibodies could modulate the regulatory potential associated with expression of CD24 in this epithelium.

Immunogenicity without immunoselection: a mutant but functional antioxidant enzyme retained in a human metastatic melanoma and targeted by CD8(+) T cells with a memory phenotype

Human melanomas can express unique tumor antigens, resulting from mutated proteins, and shared epitopes encoded for by normal genes, but these two classes of antigens have not been previously compared for immunogenicity and retention in metastatic cells. Here, we identified a new unique antigen generated by a point mutation in the peroxiredoxin 5 (Prdx5) gene in an HLA-A*0201(+) human metastatic melanoma lacking the wild-type allele. An antioxidant assay, with recombinant Prdx5 proteins, and evaluation of peroxide accumulation in transiently transfected cells, indicated that the mutant protein retained its enzymatic activity. The mutation in the Prdx5 protein did not generate a new HLA agretope but yielded an HLA-A*0201-restricted T cell epitope (Prdx5(110-119)). By HLA-tetramer analysis, in a tumor-invaded lymph node, >50% of mutant Prdx5-specific CD8(+) T cells (frequency 0.37%/CD8(+)) showed a CCR7(+/-) CD45RA(-) "T(CM)" or "T(EM)" phenotype, as found in Melan-A/MART-1-specific T cells (frequency 0.68%/CD8(+)) in the same tissue. In agreement with their memory phenotype, the Prdx5-specific T cells readily expanded in vitro in mixed lymphocyte-tumor culture, as did the Melan-/MART-1-specific T cells. By immunohistochemistry of the invaded lymph node, the mutant Prdx5 protein was expressed in all neoplastic cells, in contrast with the heterogeneous expression of shared antigens as Melan-A/MART-1, gp100 and tyrosinase. Thus, a unique tumor antigen can be as immunogenic as the melanoma differentiation antigens but, in contrast to the latter, may be retained in all metastatic cells possibly as result of the relevant cellular function exerted by the mutated protein.

Human peripheral and gastric lymphocyte responses to Helicobacter pylori NapA and AphC differ in infected and uninfected individuals

BACKGROUND

In this study, we identify the nature of the immunological response of human peripheral blood mononuclear cells (PBMC) and lamina propria gastric lymphocytes (LPL) to two Helicobacter pylori antigens, the neutrophil activating protein (NapA) and alkyl hydroperoxide reductase (AphC). These antigens were identified and selected for study based on the observation that serological recognition of these proteins was associated with H pylori negative status in humans.

AIMS

The aim was to study the serological, proliferative, and cytokine responses of PBMC and LPL, obtained from H pylori infected and uninfected individuals, to these antigens.

METHODS

Patient serum, PBMC, and LPL were used to determine antibody isotype, and proliferative and cytokine responses to recombinant forms of NapA and AphC using western blotting and ELISA.

RESULTS

Western blotting revealed antibody reactivity to recombinant NapA and AphC among the H pylori negative population studied. Both the proliferative and interferon gamma responses of PBMC and LPL to NapA and AphC were significantly higher in H pylori negative compared with H pylori positive subjects. Analysis of the IgG subclass profiles to both antigens revealed a T helper 1 associated IgG3 antibody response in uninfected individuals. However, interleukin 10 production was greater in H pylori positive individuals in response to these antigens.

CONCLUSIONS

Taken together these data are consistent with an immune response to these antigens skewed towards a T helper 1 response in the uninfected cohort.

Contribution of peroxidases in host-defense, diseases and cellular functions

Peroxidases figure prominently in biology and contribute significantly to cell biology, host defense against infection, and pathogenesis of several inflammatory diseases. These varied and diverse aspects of peroxidase biochemistry and its clinical implications will be the subjects of in-depth analysis at the 4th International peroxidase meeting held in Kyoto. Specific topics range from the molecular basis of peroxidase structure and function to the clinical consequences of autoantibodies generated against myeloperoxidase (MPO), the peroxidase present in circulating neutrophils. Consideration of novel aspects of peroxidase biology, both unanticipated biochemical properties of MPO and the potential role of MPO in the pathogenesis of inflammatory diseases such as atherosclerosis, will also be included. In addition to peroxidases, the newly expanded family of NADPH oxidases will be discussed. We hope that this collection of scientists who share a common interest in peroxidase biology but each possess expertise in distinctly different aspects of the subject will provide a setting for spirited discussion and a lively exchange of views to yield advances in understanding and to create new applications of those insights to benefit clinical medicine, agriculture and industry.

Allergen extracts directly mobilize and activate human eosinophils

Allergic diseases are characterized by the presence of eosinophils, which are recruited to the affected tissues by chemoattractants produced by T cells, mast cells and epithelium. Our objective was to evaluate if allergens can directly activate human eosinophils. The capacity of purified allergen extracts to elicit eosinophil chemotaxis, respiratory burst, degranulation and up-regulation of the adhesion molecule complement receptor 3 (CR3) was determined in eosinophils isolated from healthy blood donors. Eosinophils stimulated with an extract from house dust mite (HDM) released the granule protein major basic protein (MBP) and up-regulated the surface expression of CR3. Cat allergen extracts also induced the up-regulation of CR3, but not the release of MBP; instead cat, as well as birch and grass allergens, elicited the release of eosinophil peroxidase (EPO). In addition, grass pollen extract caused the secretion of MBP. None of the allergens stimulated eosinophilic cationic protein release, nor production of free oxygen radicals. Both HDM and birch extracts were chemotactic for eosinophils. These findings establish that common aeroallergens can directly activate eosinophils in vitro. We propose that eosinophil activation in vivo is not exclusively mediated by cytokines and chemokines of the allergic inflammatory reaction, but could partly be the result of direct interaction between allergens and eosinophils.

Histological evidence of redox system breakdown caused by superoxide dismutase 1 (SOD1) aggregation is common to SOD1-mutated motor neurons in humans and animal models

Living cells produce reactive oxygen species (ROSs). To protect themselves from these ROSs, the cells have developed both an antioxidant system containing superoxide dismutase 1 (SOD1) and a redox system including peroxiredoxin2 (Prx2, thioredoxin peroxidase) and glutathione peroxidase1 (GPx1): SOD1 converts superoxide radicals into hydrogen peroxide (H2O2), and H2O2 is then converted into harmless water (H2O) and oxygen (O2) by Prx2 and GPx1 that directly regulate the redox system. To clarify the biological significance of the interaction of the redox system (Prx2/GPx1) with SOD1 in SOD1-mutated motor neurons in vivo, we produced an affinity-purified rabbit antibody against Prx2 and investigated the immunohistochemical localization of Prx2 and GPx1 in neuronal Lewy body-like hyaline inclusions (LBHIs) in the spinal cords of familial amyotrophic lateral sclerosis (FALS) patients with a two-base pair deletion at codon 126 and an Ala-->Val substitution at codon 4 in the SOD1 gene, as well as in transgenic rats expressing human SOD1 with H46R and G93A mutations. The LBHIs in motor neurons from the SOD1-mutated FALS patients and transgenic rats showed identical immunoreactivities for Prx2 and GPx1: the reaction product deposits with the antibodies against Prx2 and GPx1 were localized in the LBHIs. In addition, the localizations of the immunoreactivities for SOD1 and Prx2/GPx1 were similar in the inclusions: the co-aggregation of Prx2/GPx1 with SOD1 in neuronal LBHIs in mutant SOD1-related FALS patients and transgenic rats was evident. Based on the fact that Prx2/GPx1 directly regulates the redox system, such co-aggregation of Prx2/GPx1 with SOD1 in neuronal LBHIs may lead to the breakdown of the redox system itself, thereby amplifying the mutant SOD1-mediated toxicity in mutant SOD1-linked FALS patients and transgenic rats expressing human mutant SOD1.

Functional expression and characterization of Echinococcus granulosus thioredoxin peroxidase suggests a role in protection against oxidative damage

A full-length cDNA sequence coding for Echinococcus granulosus thioredoxin peroxidase (EgTPx) was isolated from a sheep strain protoscolex cDNA library by immunoscreening using a pool of sera from mice infected with oncospheres. EgTPx expressed as a fusion protein with glutathione S-transferase (GST) exhibited significant thiol-dependent peroxidase activity that protected plasmid DNA from damage by metal-catalyzed oxidation (MCO) in vitro. Furthermore, the suggested antioxidant role for EgTPx was reinforced in an in vivo assay, whereby its expression in BL21 bacterial cells markedly increased the tolerance and survival of the cells to high concentrations of H2O2 compared with controls. Immunolocalization studies revealed that EgTPx was specifically expressed in all tissues of the protoscolex and brood capsules. Higher intensity of labelling was detected in many, but not all, calcareous corpuscle cells in protoscoleces. The purified recombinant EgTPx protein was used to screen sera from heavily infected mice and patients with confirmed hydatid infection. Only a portion of the sera reacted positively with the EgTPx-GST fusion protein in Western blots, suggesting that EgTPx may form antibody-antigen complexes or that responses to the EgTPx antigen may be immunologically regulated. Recombinant EgTPx may prove useful for the screening of specific inhibitors that could serve as new drugs for treatment of hydatid disease. Moreover, given that TPx from different parasitic phyla were phylogenetically distant from host TPx molecules, the development of antiparasite TPx inhibitors that do not react with host TPx might be feasible.

Expression of peroxiredoxins in bovine oocytes and embryos produced in vitro

Peroxiredoxins (PRDXs) form a family of peroxidases involved in antioxidant protection and cell signaling. Due to their peroxide reductase activity, these enzymes might be involved in fine-tuning peroxide levels in embryos during in vitro production. In this study, RT-PCR was used to examine the expression of the six PRDX isoforms (PRDX1 to PRDX6) in bovine oocytes and embryos. PRDXs were detected in oocytes both before and after in vitro maturation. Besides, PRDX6 was up-regulated after maturation. Single embryos were analyzed from the two-cell to the blastocyst stages. PRDX1 and PRDX5 transcripts were detected throughout development. PRDX2, PRDX3, and PRDX6 were not expressed around the 9- to 16-cell stage. PRDX4 transcripts were weakly detected in pools of embryos from the 9- to 16-cell stage onwards. In situ immunodetection of PRDX5, which was previously reported to exhibit the widest subcellular distribution among PRDXs in adult mammalian cells, showed a mitochondrial distribution pattern in the bovine embryo. Finally, the potential modulation by oxidative stress of PRDX expression around the major embryonic genome activation was evaluated by culturing embryos under 20% O2 instead of 5%. No significant difference in the pattern of PRDX expression was observed under 20% O2. In conclusion, our data show for the first time that PRDXs are expressed in mammalian oocytes and early embryos. Moreover, the bovine transcripts exhibit various patterns of expression that might be related to the potential role of PRDXs in oocyte maturation and embryo development.

Purification, characterization, and physiological response of a catalase-peroxidase in Mycobacterium sp. strain JC1 DSM 3803 grown on methanol

A novel catalase-peroxidase (CP) from methanol-grown cells of Mycobacterium sp. strain JC1 was purified. The CP exhibited properties of both typical mycobacterial CPs (i.e. strict pH optimum, labile to heat treatment, capable of oxidizing NADH, and resistant to inhibition by 3-amino-1,2,4-triazole) and true catalases (i.e. stable against ethanol-chloroform treatment). The enzyme oxidized methanol and shared common antigenic groups with other mycobacteria. Isoniazid had almost no effect on the growth and expression of CP but inhibited the enzyme activity to some extent. Sodium nitroprusside arrested the growth but strongly stimulated the expression of CP with a concomitant increase in activity after the mid-exponential growth phase.

Relationship of dehydroepiandrosterone and its 7-hydroxylated metabolites to thyroid parameters and sex hormone-binding globulin (SHBG) in healthy subjects

The concentrations of four immunomodulatory steroids, namely dehydroepiandrosterone (DHEA), its sulfate and its 7-hydroxylated metabolites, and sex hormone-binding globulin (SHBG) and major laboratory parameters of thyroid function were determined in sera from 104 healthy females and 48 males, screened for iodine deficiency in one region of the Czech Republic. The mutual relationships of the laboratory parameters were investigated by using four statistical approaches: correlation analysis, principal component analysis, canonical correlation and linear model relationship. In addition to expected correlations among thyroid parameters and substrate-product relationships among the steroids, several new relationships were revealed: The only thyroid parameter tightly correlating with SHBG was free triiodothyronine. The latter hormone was also associated with one of the 7-OH-DHEA epimers, namely with 7beta-OH-DHEA. Thyroid hormones are known to possess thermogenic properties, as does another 7-oxygenated DHEA metabolite, 7-oxo-DHEA, the major metabolite of which is 7beta-OH-DHEA. It may indicate a link between the two thermogenic factors. The results should serve for further investigation of changes in the thyroid hormone concentrations, together with SHBG and dehydroepiandrosterone metabolites, under various pathological situations.

Identification of suberization-associated anionic peroxidase as a possible allergenic protein from tomato

A 45 kDa protein, which is recognized by IgE antibodies in sera of food-allergic patients, was purified and characterized as an allergenic protein from the tomato. The IgE-binding protein purified from tomato extract was found to be a glycoprotein with a molecular weight of approximately 45,000, an isoelectric point of 4.2, and no free N-terminal amino group. Furthermore, it was shown that the purified protein had peroxidase activity. From the amino acid sequence of a peptide fragment prepared by lysylendopeptidase digestion, the allergenic protein was identified to be the tomato suberization-associated anionic peroxidase 1 known as one of the pathogenesis-related proteins widely distributed in plants. These properties suggested the protein isolated from tomato to be a new allergenic protein in plant foodstuffs.

Perils of immunohistochemistry: variability in staining specificity of commercially available COX-2 antibodies on human colon tissue

We assessed the immunohistochemical (IHC) staining patterns of three commercially available COX-2 antibodies in human tissues. The location of positive stain in sequential serial 4-mu sections of formalin fixed, paraffin embedded tissue differed considerably. Staining patterns ranged from diffuse cytoplasmic to occasional perinuclear staining. Thus, marked variability in staining results from use of different antibodies, making it important to consider the antibody used when comparing reports of COX-2 staining from different investigators.

A regulating element essential for PDGFRA transcription is recognized by neural tube defect-associated PRX homeobox transcription factors

We have previously shown that deregulated expression of the platelet-derived growth factor alpha-receptor (PDGFRA) can be associated with neural tube defects (NTDs) in both men and mice. In the present study, we have investigated the transcription factors that control the up-regulation of PDGFRA expression during differentiation of early embryonic human cells in culture. In Tera-2 embryonal carcinoma cells, PDGFRA expression is strongly enhanced upon differentiation induced by retinoic acid and cAMP treatment. Here we show that the corresponding increase in promoter activity is controlled by an ATTA-sequence-containing element located near the transcription initiation site, which is bound by a transcriptional complex that includes PBX and PRX homeobox transcription factors. Mutation of the putative binding sites for these transcription factors results in strong impairment of PDGFRA promoter activity in differentiated cells. Since functional inactivation of Prx genes has been associated with NTDs in mice, these data support a model in which improper PDGFRA expression as a result of mutations in or altered binding of its upstream regulators may be causally related to NTDs.

Hemoabzymes: towards new biocatalysts for selective oxidations

Catalytic antibodies with a metalloporphyrin cofactor or <<hemoabzymes>>, used as models for hemoproteins like peroxidases and cytochrome P450, represent a promising route to catalysts tailored for selective oxidation reactions. A brief overview of the literature shows that until now, the first strategy for obtaining such artificial hemoproteins has been to produce antiporphyrin antibodies, raised against various free-base, N-substituted Sn-, Pd- or Fe-porphyrins. Five of them exhibited, in the presence of the corresponding Fe-porphyrin cofactor, a significant peroxidase activity, with k(cat)/K(m) values of 3.7 x 10(3) - 2.9 x 10(5) M(-1) min(-1). This value remained, however, low when compared to that of peroxidases. This strategy has also led to a few models of cytochrome P450. The best of them, raised against a water-soluble tin(IV) porphyrin containing an axial alpha-naphtoxy ligand, was reported to catalyze the stereoselective oxidation of aromatic sulfides by iodosyl benzene using a Ru(II)-porphyrin cofactor. The relatively low efficiency of the porphyrin-antibody complexes is probably due, at least in part, to the fact that no proximal ligand of Fe has been induced in those antibodies. We then proposed to use, as a hapten, microperoxidase 8 (MP8), a heme octapeptide in which the imidazole side chain of histidine 18 acts as a proximal ligand of the iron atom. This led to the production of seven antibodies recognizing MP8, the best of them, 3A3, binding it with an apparent binding constant of 10(-7) M. The corresponding 3A3-MP8 complex was found to have a good peroxidase activity characterized by a k(cat)/K(m) value of 2 x 10(6) M(-1) min(-1), which constitutes the best one ever reported for an antibody-porphyrin complex. Active site topology studies suggest that the binding of MP8 occurs through interactions of its carboxylate substituents with amino acids of the antibody and that the protein brings a partial steric hindrance of the distal face of the heme of MP8. Consequently, the use of the 3A3-MP8 complexes for the selective oxidation of substrates, such as sulfides, alkanes and alkenes will be undertaken in the future.

Purification and characterization of soluble peroxidase from oil palm (Elaeis guineensis Jacq) leaf

Soluble peroxidase (POD) from oil palm leaf was purified by (NH(4))(2)SO(4) precipitation, anion exchange chromatography and molecular exclusion chromatography. The purification grade obtained was 429 yielding 54% of the enzyme activity. Electrophoresis of purified enzyme under denatured conditions revealed M(r) of 48+/-2 kDa. It has an optimum pH of 5 and it exhibited very high pH and thermal stabilities. K(m) for guaiacol, ABTS and pyrogallol were 3.96, 1 and 0.84 mM, respectively. Immunocytochemical localization studies showed that soluble POD was mainly located in the vascular bundles and epidermis of leaf.

Immunization with a polyprotein vaccine consisting of the T-Cell antigens thiol-specific antioxidant, Leishmania major stress-inducible protein 1, and Leishmania elongation initiation factor protects against leishmaniasis

Development of an effective vaccine against Leishmania infection is a priority of tropical disease research. We have recently demonstrated protection against Leishmania major in the murine and nonhuman primate models with individual or combinations of purified leishmanial recombinant antigens delivered as plasmid DNA constructs or formulated with recombinant interleukin-12 (IL-12) as adjuvant. In the present study, we immunized BALB/c mice with a recombinant polyprotein comprising a tandem fusion of the leishmanial antigens thiol-specific antioxidant, L. major stress-inducible protein 1 (LmSTI1), and Leishmania elongation initiation factor (LeIF) delivered with adjuvants suitable for human use. Aspects of the safety, immunogenicity, and vaccine efficacy of formulations with each individual component, as well as the polyprotein referred to as Leish-111f, were assessed by using the L. major challenge model with BALB/c mice. No adverse reactions were observed when three subcutaneous injections of the Leish-111f polyprotein formulated with either MPL-squalene (SE) or Ribi 529-SE were given to BALB/c mice. A predominant Th1 immune response characterized by in vitro lymphocyte proliferation, gamma interferon production, and immunoglobulin G2A antibodies was observed with little, if any, IL-4. Moreover, Leish-111f formulated with MPL-SE conferred immunity to leishmaniasis for at least 3 months. These data demonstrate success at designing and developing a prophylactic leishmaniasis vaccine that proved effective in a preclinical model using multiple leishmanial antigens produced as a single protein delivered with a powerful Th1 adjuvant suitable for human use.

Vaccination with plasmid DNA encoding TSA/LmSTI1 leishmanial fusion proteins confers protection against Leishmania major infection in susceptible BALB/c mice

We have recently shown that a cocktail containing two leishmanial recombinant antigens (LmSTI1 and TSA) and interleukin-12 (IL-12) as an adjuvant induces solid protection in both a murine and a nonhuman primate model of cutaneous leishmaniasis. However, because IL-12 is difficult to prepare, is expensive, and does not have the stability required for a vaccine product, we have investigated the possibility of using DNA as an alternative means of inducing protective immunity. Here, we present evidence that the antigens TSA and LmSTI1 delivered in a plasmid DNA format either as single genes or in a tandem digene construct induce equally solid protection against Leishmania major infection in susceptible BALB/c mice. Immunization of mice with either TSA DNA or LmSTI1 DNA induced specific CD4(+)-T-cell responses of the Th1 phenotype without a requirement for specific adjuvant. CD8 responses, as measured by cytotoxic-T-lymphocyte activity, were generated after immunization with TSA DNA but not LmSTI1 DNA. Interestingly, vaccination of mice with TSA DNA consistently induced protection to a much greater extent than LmSTI1 DNA, thus supporting the notion that CD8 responses might be an important accessory arm of the immune response for acquired resistance against leishmaniasis. Moreover, the protection induced by DNA immunization was specific for infection with Leishmania, i.e., the immunization had no effect on the course of infection of the mice challenged with an unrelated intracellular pathogen such as Mycobacterium tuberculosis. Conversely, immunization of BALB/c mice with a plasmid DNA that is protective against challenge with M. tuberculosis had no effect on the course of infection of these mice with L. major. Together, these results indicate that the protection observed with the leishmanial DNA is mediated by acquired specific immune response rather than by the activation of nonspecific innate immune mechanisms. In addition, a plasmid DNA containing a fusion construct of the two genes was also tested. Similarly to the plasmids encoding individual proteins, the fusion construct induced both specific immune responses to the individual antigens and protection against challenge with L. major. These results confirm previous observations about the possibility of DNA immunization against leishmaniasis and lend support to the idea of using a single polygenic plasmid DNA construct to achieve polyspecific immune responses to several distinct parasite antigens.

Sensitive detection and quantitation of mouse eosinophils in tissues using an enzymatic eosinophil peroxidase assay: its use to rapidly measure pulmonary eosinophilia during experimental respiratory syncytial virus infection of mice

Eosinophils are granular proinflammatory leukocytes implicated in the pathogenesis of several inflammatory processes including allergy, asthma, and in the development of enhanced disease during respiratory syncytial virus (RSV) infection. Here, we adapted a colorimetric assay to measure eosinophil peroxidase (EPO) activity in inflamed mouse lung tissue in order to quantitate pulmonary eosinophilia during experimental RSV infection. Using the substrate o-phenylenediamine dihydrochloride (OPD) in the presence of bromide ions, we show that this assay is able to quantitate limiting numbers of eosinophils in lung tissue homogenates even in the presence of large numbers of infiltrating neutrophils and macrophages. The ability of the EPO assay to selectively quantitate eosinophils in a complex tissue inflammatory infiltrate demonstrates the usefulness of this enzymatic assay as a rapid and sensitive method to quantitate the influx of eosinophils into inflamed mouse tissue such as the lung during experimental RSV infection without reliance on morphologic criteria to identify murine eosinophils in tissues or bronchial lavage fluid.

Nonredundant antioxidant defense by multiple two-cysteine peroxiredoxins in human prostate cancer cells

BACKGROUND

Peroxiredoxins (Prxs) are antioxidant enzymes expressed by most free-living organisms, often in multiple isoforms. Because mammalian Prxs have not been experimentally deleted or inhibited, it is not known how much they contribute to antioxidant defense, nor whether the multiple isoforms afford redundant or additive protection.

MATERIALS AND METHODS

Expression of the four members of the 2-Cys family of human Prxs was tested in human tumor cell lines. Monospecific antibodies were developed and used to monitor the extent and specificity of inhibition of expression of each isoform in prostate cancer cells stably transfected with antisense constructs.

RESULTS

Seventeen tumor lines transcribed genes for all four human Prxs. Prostate cancer cells coexpressed each isoform at the protein level. Stable transfection with antisense allowed partial, selective suppression of Prx 1, 2, 3, or 4. Prostate cancer cells were rendered more sensitive to hydrogen peroxide or an organic hydroperoxide when Prx 1, 2, or 3 but not 4 was partially suppressed, bringing them into the range of sensitivity of mouse cells. The effect of partially suppressing a single Prx was comparable to that of depleting glutathione. In contrast, sensitization to adriamycin, an antitumor agent with a redox-active quinone, followed the partial suppression of Prxs 1, 2, or 4 but not 3. Individual suppression of Prxs 1-4 had no effect on sensitivity of the cells to reactive nitrogen intermediates, tumor necrosis factor (TNF), paclitaxel (Taxol), or etoposide.

CONCLUSIONS

The 2-Cys Prxs act in a mutually nonredundant and sometimes stress-specific fashion to protect human cells from oxidant injury. The substantial resistance of human cells to hydroperoxides may result in part from the additive action of multiple Prxs.

Comparative analysis of Prx1 and Prx2 expression in mice provides evidence for incomplete compensation

The family of paired-related homeobox genes to which Prx1 and Prx2 belong plays an integral role in limb and craniofacial development, as evidenced by both transgenic mice and in situ hybridization data. However, little is known about protein expression of these homeodomain transcription factors. Recent studies in our lab have established the pattern of Prx1 protein expression during normal mouse embryogenesis. Here we present a comparative analysis of Prx1 and Prx2 protein expression in the developing mouse using a novel anti-Prx2 antibody reagent.

Immune response to a 26-kDa protein, alkyl hydroperoxide reductase, in Helicobacter pylori-infected Mongolian gerbil model

BACKGROUND

The host immune response is thought to play an important role in the outcome of Helicobacter pylori infection. The successful development of the H. pylori-infected Mongolian gerbil model that mimics human disease has enabled study of the antibody response against H. pylori antigens.

MATERIALS AND METHODS

Serum samples from ulcer and carcinogenesis models of H. pylori-infected gerbils were used to screen for H. pylori antigens that cause a humoral immune response in the infected hosts. H. pylori alkyl hydroperoxide reductase (AhpC) is one such antigen on which we report here. The tsaA gene encoding AhpC was amplified by PCR from H. pylori ATCC 43504 strain, cloned into pMAL(TM)-c2 expression vector and expressed in Escherichia coli. Maltose-binding protein fusion protein (MBP-AhpC) was purified by a MBP affinity column. Using purified recombinant AhpC protein as an antigen, the antibody response and changes of antibody levels against AhpC in the gerbil models were studied by Western blotting and ELISA.

RESULTS

Antibody against AhpC was negative in the early stages of infection, and became positive in the gerbils with the emergence of gastric diseases such as chronic active gastritis, gastric ulcer and gastric cancer. The antibody levels (ELISA) increased gradually over time and were higher in gerbils with gastric ulcer than that in gerbils without ulcers.

CONCLUSIONS

Use of the gerbil model that mimics human H. pylori infection is likely to provide insights into the role of H. pylori-specific antigens possibly related to the subsequent development of gastric diseases.

AhpC, AhpD, and a secreted 14-kilodalton antigen from Mycobacterium avium subsp. paratuberculosis distinguish between paratuberculosis and bovine tuberculosis in an enzyme-linked immunosorbent assay

Sera from cattle naturally infected with Mycobacterium avium subsp. paratuberculosis (n = 56) and naturally (n = 4) and experimentally (n = 8) infected with Mycobacterium bovis were tested for the presence of antibodies against paratuberculosis antigens. An enzyme-linked immunosorbent assay (ELISA) was established based on absorption of M. avium subsp. paratuberculosis antigens on a hyperimmune antiserum against M. avium subsp. avium proteins in order to remove cross-reacting antigens. This absorbed-antigen ELISA recognized 66% of animals with paratuberculosis (37 of 56), while none of the animals with naturally occurring bovine tuberculosis (TB) had detectable antibodies. However, the animals with experimental bovine TB also responded in this ELISA. Similar results were found in a commercial ELISA, showing that neither of these tests was able to distinguish between paratuberculosis and bovine TB. The sera were further tested for antibody activities against purified AhpC and AhpD, which are proteins constitutively expressed by M. avium subsp. paratuberculosis, and against a secreted 14-kDa protein present in culture filtrates from the M. avium complex. Elevated antibody levels to AhpC, AhpD, and the 14-kDa antigen were found in 27% (13 of 48), 15% (7 of 48), and 27% (13 of 48), respectively, of the cattle with paratuberculosis. Together these ELISAs were positive with 35% (17 of 48) of the animals. None of the animals with bovine TB had detectable antibodies against any of the purified proteins despite their high levels of cross-reacting antibodies. These results show that purified specific antigens are needed to differentiate between paratuberculosis and bovine TB in ELISA.