The role of endosymbiotic Wolbachia bacteria in the pathogenesis of river blindness. Andre AS, Blackwell NM, Hall LR, Hoerauf A, Bratting NW, Volkmann L, Taylor MJ, Ford L, Hise AG, Lass JH, Diaconu E, Pearlman E.∗ ∗Department of Ophthalmology, University Hospitals of Cleveland and Case Western R...more
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As research progress has led to programs for the elimination of onchocerciasis as a public health problem, research must now be intensified to protect elimination efforts. A profound understanding of the immunology in the human-parasite... more
As research progress has led to programs for the elimination of onchocerciasis as a public health problem, research must now be intensified to protect elimination efforts. A profound understanding of the immunology in the human-parasite relationship is required for predicting the impacts of an altered immune response in a population post-microfilaricide treatment, and for the development of a vaccine against onchocerciasis, a highly desirable tool to guarantee sustained elimination success. This article summarizes the recent advancements in understanding the human immune mechanisms against onchocerciasis, and focuses on the new concept of T-cell suppressor responses as a major counterbalance mechanism for effector responses driven by T helper 1 and T helper 2 cells against the filarial worms.
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Transforming growth factor-beta (TGF-beta) is a highly conserved cytokine that has a well-known regulatory role in immunity, but also in organ development of most animal species including helminths. Homologous tgf-b genes and mRNA have... more
Transforming growth factor-beta (TGF-beta) is a highly conserved cytokine that has a well-known regulatory role in immunity, but also in organ development of most animal species including helminths. Homologous tgf-b genes and mRNA have been detected in the filaria Brugia malayi. The in situ protein expression is unknown for filariae. Therefore, we examined several filariae for the expression and localization of latent (stable) TGF-beta in adult and larval stages. A specific goat anti-human latency associated protein (LAP, TGF-beta 1) antibody, purified by affinity chromatography, was used for light and electron microscopic immunohistochemistry. Adult Onchocerca volvulus, Onchocerca gibsoni, Onchocerca ochengi, Onchocerca armillata, Onchocerca fasciata, Onchocerca flexuosa, Wuchereria bancrofti, Dirofilaria sp., B. malayi, and infective larvae of W. bancrofti reacted with the antibody. Labeling of worm tissues varied between negative and all degrees of positive reactions. Latent TGF-beta was strongly expressed adjacent to the cell membranes of the hypodermis, epithelia, and muscles and adjacent to many nuclei in all organs. TGF-beta was well expressed in worms without Wolbachia endobacteria eliminated by doxycycline treatment. Pleomorphic neoplasms in O. volvulus were also labeled. We conclude that latent TGF-beta protein is expressed by filariae independently of Wolbachia, possibly regulating worm tissue homeostasis.
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Research Interests: Microbiology, Immunology, Immune response, Medical Microbiology, Biology, and 15 moreMalaria, Medicine, Humans, Child, Animals, Antibody, Asymptomatic, Cerebral Malaria, Enzyme Linked Immunosorbent Assay, Antigen, immunoglobulin G, Case Control Studies, Child preschool, Antibody Response, and Malaria Falciparum
... Michael Saeftel, Lars Volkmann, Simone Korten, Norbert Brattig, Khaled Al-Qaoud 1 1 , Bernhard Fleischer, Achim Hoerauf Corresponding Author Contact ... IFN)-γ is essential for encapsulation of adult filarial worms in inflammatory... more
... Michael Saeftel, Lars Volkmann, Simone Korten, Norbert Brattig, Khaled Al-Qaoud 1 1 , Bernhard Fleischer, Achim Hoerauf Corresponding Author Contact ... IFN)-γ is essential for encapsulation of adult filarial worms in inflammatory nodules and for normal worm clearance. ...
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HSP60 functions as a chemoattractant and activator of neutrophil granulocytes. Neutrophil granulocytes belong to the first cells that enter sites of infection, where they eliminate infiltrating pathogens via phagocytosis and the release... more
HSP60 functions as a chemoattractant and activator of neutrophil granulocytes. Neutrophil granulocytes belong to the first cells that enter sites of infection, where they eliminate infiltrating pathogens via phagocytosis and the release of antimicrobial mediators. Hence, recruitment of neutrophils and activation of neutrophil microbicidal functions are crucial steps in the early containment of infection. In this study, we show that hHSP60 binds to murine and human PMN strongly and specifically. We demonstrate that HSP60 serves as a chemoattractant and modulates neutrophil functions. Human PMN were incubated with HSP60 alone or prior to stimulation with fMLP or PMA acetate. We observed that HSP60, although not inducing neutrophil release of ROS and degranulation itself, strongly enhanced the production of reactive oxygen induced by PMA and the release of primary granule enzymes induced by both secondary stimuli. This sensitization of PMN was HSP60-specific. Moreover, PMN that had bee...
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Immune responses of individuals infected with filarial nematodes are characterized by a marked cellular hyporesponsiveness and a shift of the cytokine balance toward a Th2/Th3 response. This modulation of cellular immune responses is... more
Immune responses of individuals infected with filarial nematodes are characterized by a marked cellular hyporesponsiveness and a shift of the cytokine balance toward a Th2/Th3 response. This modulation of cellular immune responses is considered as an important mechanism to avoid inflammatory immune responses that could eliminate the parasites. We investigated the immunomodulatory potential of a secreted cysteine protease inhibitor (onchocystatin) of the human pathogenic filaria Onchocerca volvulus. Recombinant onchocystatin (rOv17), a biologically active cysteine protease inhibitor that inhibited among others the human cysteine proteases cathepsins L and S, suppressed the polyclonally stimulated and the Ag-driven proliferation of human PBMC. Stimulated as well as unstimulated PBMC in the presence of rOv17 produced significantly more IL-10, which was paralleled in some situations by a decrease of IL-12p40 and preceded by an increase of TNF-α. At the same time, rOv17 reduced the expre...
Research Interests: Immunology, Biology, Cytokines, Macrophages, Immunology of the Gut, and 15 moreMedicine, Humans, Female, Animals, Monoclonal Antibodies, CD, Immune system, Monocytes, Cysteine endopeptidases, Gene Expression Regulation, Interleukin, Cysteine Proteinase Inhibitors, Cysteine Protease, phytohemagglutinins, and cathepsin L
Malaria remains the single most frequent cause of death in Africa, killing one child every 30 s, but treatment decisions are often made only on clinical diagnosis, as laboratory techniques to confirm the clinical suspicion are labor... more
Malaria remains the single most frequent cause of death in Africa, killing one child every 30 s, but treatment decisions are often made only on clinical diagnosis, as laboratory techniques to confirm the clinical suspicion are labor intensive and costly. In this study, we evaluated the recently developed Partec rapid malaria test (PM) for the detection of Plasmodium spp. in human blood from patients in an area where malaria is endemic and compared the results with those of thick blood film Giemsa stain (GS) in terms of its performance and operational characteristics, using real-time (RT) PCR as the gold standard. The sensitivities of the PM and the GS were 62.2% (95% CI, 56.3 to 67.8) and 61.8% (95% CI, 55.9 to 67.4), respectively, while the specificities were 96.0% (95% CI, 92.3 to 98.3) and 98% (95% CI, 95.0 to 99.5), respectively. There was an excellent agreement between the results for the PM and those of the GS ( k [level of agreement] = 0.96; P < 0.001). The results for the...
Research Interests: Parasitology, Microscopy, Africa, Biology, Malaria, and 15 moreMedicine, Plasmodium, Clinical Microbiology, Biological Sciences, real time PCR, Humans, Clinical, Blood, Polymerase Chain Reaction, Infant, Newborn Infant, Gold Standard, Sensitivity and Specificity, Child preschool, and Medical and Health Sciences
Research Interests: Microbiology, Parasitology, Medical Microbiology, Malaria, Adolescent, and 15 moreMedicine, Plasmodium, Humans, Child, Blood sampling, Male, Research article, Clinical Sciences, Diagnostic Test, Disease Management, Diagnosis of malaria, Child preschool, Rapid diagnostic test, Diagnostic Tool, and Field Test
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The front line molecules from filarial worms and other nematodes or helminthes are their Excretory-Secretory (ES) products. Their interaction with the host cells, proteins and immune system accounts for the skin and eye pathology or... more
The front line molecules from filarial worms and other nematodes or helminthes are their Excretory-Secretory (ES) products. Their interaction with the host cells, proteins and immune system accounts for the skin and eye pathology or hyposensitivity observed in human onchocerciasis. ES products and adult worms' crude extracts from Onchocerca ochengi, a filarial nematode that infects the African zebu cattle, were utilized in the present study as a model for studying Onchocerca volvulus that causes river blindness in man. The ES products were generated from adult male and female worms in vitro and analyzed with poly acrylamide gel electrophoresis (PAGE) and enzyme-linked immunosorbent assay (ELISA) using sera from Onchocerca-infected cattle and humans. The cattle sera were collected from a herd that had been exposed for six years to natural transmission of Onchocerca spp. The expressed reactivity was evaluated and differences analyzed statistically using Kruskal-Wallis rank and Chi...
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River blindness, caused by the filarial parasite Onchocerca volvulus, is a major socio-economic and public health problem in Sub-Saharan Africa. In January 2015, The Onchocerciasis Vaccine for Africa (TOVA) Initiative has been launched... more
River blindness, caused by the filarial parasite Onchocerca volvulus, is a major socio-economic and public health problem in Sub-Saharan Africa. In January 2015, The Onchocerciasis Vaccine for Africa (TOVA) Initiative has been launched with the aim of providing new tools to complement mass drug administration (MDA) of ivermectin, thereby promoting elimination of onchocerciasis in Africa. In this context we here present Onchocerca volvulus glyceraldehyde-3-phosphate dehydrogenase (Ov-GAPDH) as a possible DNA vaccine candidate. We report that in a laboratory model for filariasis, immunization with Ov-GAPDH led to a significant reduction of adult worm load and microfilaraemia in BALB/c mice after challenge infection with the filarial parasite Litomosoides sigmodontis. Mice were either vaccinated with Ov-GAPDH.DNA plasmid (Ov-pGAPDH.DNA) alone or in combination with recombinantly expressed Ov-GAPDH protein (Ov-rGAPDH). During the following challenge infection of immunized and control mi...
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Research Interests: Molecular Biology, Immune response, Biology, Medicine, Phylogeny, and 15 moreCell line, Humans, Intestinal Mucosa, Female, Animals, Male, Monocytes, Heat Shock Proteins, Protein isoforms, Heat Shock Protein, Basic Medicine, Amino Acid Sequence, Biochemistry and cell biology, Molecular Sequence Data, and Medical biochemistry and metabolomics
Helminths are the largest and most complex pathogens to invade and live within the human body. Since they are not able to outpace the immune system by rapid antigen variation or faster cell division or retreat into protective niches not... more
Helminths are the largest and most complex pathogens to invade and live within the human body. Since they are not able to outpace the immune system by rapid antigen variation or faster cell division or retreat into protective niches not accessible to immune effector mechanisms, their long-term survival depends on influencing and regulating the immune responses away from the mode of action most damaging to them. Immunologists have focused on the excretory and secretory products that are released by the helminths, since they can change the host environment by modulating the immune system. Here we give a brief overview of the helminth-associated immune response and the currently available helminth secretome data. We introduce some major secretome-derived immunomodulatory molecules and describe their potential mode of action. Finally, the applicability of helminth-derived therapeutic proteins in the treatment of allergic and autoimmune inflammatory disease is discussed.
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Human infections with the tissue nematode Onchocerca volvulus result in a variety of clinical conditions that possibly include protective immunity. In a West African area hyperendemic for human onchocerciasis, 120 residents were... more
Human infections with the tissue nematode Onchocerca volvulus result in a variety of clinical conditions that possibly include protective immunity. In a West African area hyperendemic for human onchocerciasis, 120 residents were classified according to clinical and laboratory findings as presenting with generalized onchocerciasis, localized onchocerciasis, or as being putatively immune. The three groups differed in the distribution of HLA-D variants as determined by DNA typing. The most pronounced differences were found among alleles of the DQ loci. The haplotype DQA1*0501-DQB1*0301 was significantly more frequent among putatively immune individuals than among patients with generalized or localized disease. Conversely, DQA1*0101-DQB1*0501 and, independently, the allele DQB1*0201 were more frequent in generalized disease than in localized disease or putative immunity. In these correlations, the frequencies of allelic variants were in localized disease intermediate to those of the two...
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SUMMARYUp to 5% of untreated female Onchocerca volvulus filariae develop potentially fatal pleomorphic neoplasms, whose incidence is increased following ivermectin treatment. We studied the occurrence of 8 filarial proteins and of... more
SUMMARYUp to 5% of untreated female Onchocerca volvulus filariae develop potentially fatal pleomorphic neoplasms, whose incidence is increased following ivermectin treatment. We studied the occurrence of 8 filarial proteins and of Wolbachia endobacteria in the tumor cells. Onchocercomas from patients, untreated and treated with antibiotics and anthelminthics, were examined by immunohistology. Neoplasms were diagnosed in 112 of 3587 female and in 2 of 1570 male O. volvulus. The following proteins and other compounds of O. volvulus were expressed in the cells of the neoplasms: glutathione S-transferase 1, lysosomal aspartic protease, cAMP-dependent protein kinase, alpha-enolase, aspartate aminotransferase, ankyrin E1, tropomyosin, heat shock protein 60, transforming growth factor-beta, and prostaglandin E2. These findings prove the filarial origin of the neoplasms and confirm the pleomorphism of the tumor cells. Signs indicating malignancy of the neoplasms are described. Wolbachia wer...
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Strongyloidiasis is a tropical parasitosis characterized by an alternation between free-living and parasitic stages, and by long-term infection via autoinfection. Since invasion and evasion processes of helminth parasites are... more
Strongyloidiasis is a tropical parasitosis characterized by an alternation between free-living and parasitic stages, and by long-term infection via autoinfection. Since invasion and evasion processes of helminth parasites are substantially attained by the involvement of excretory-secretory products, we identified and characterized the 13.5 kDa macrophage migration inhibitory factor (MIF)-like protein in Strongyloides ratti. Sra-MIF is mainly secreted from the infective stage larvae (iL3), while the transcript was found at lower levels in parasitic and free-living females. Sequence analysis of the full-length cDNA showed the highest homology to the human pathogen Strongyloides stercoralis, and both are related to the MIF type-2. Unlike other mif genes, the Sra-mif includes no intron. The protein was recombinantly expressed in Escherichia coli and purified. Sra-MIF exhibited no in vitro tautomerase activity. The exposure of Sra-MIF to the host immune system is confirmed by high IgG reactivities found in the hosts&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; sera following infection or immunization. Flow cytometric analysis indicated the binding of Sra-MIF to the monocytes/macrophage lineage but not to peripheral lymphocytes. After exposure to Sra-MIF, monocytes released IL-10 but not TNF-alpha suggesting the involvement of the secreted parasite MIF in host immune responses.
Research Interests: Microbiology, Immunology, Immune response, Flow Cytometry, Medical Microbiology, and 15 moreBiology, Macrophages, Medicine, Humans, Escherichia coli, Female, Animals, Male, Immune system, Monocytes, Amino Acid Sequence, immunoglobulin G, Interleukin, Molecular Sequence Data, and Macrophage migration inhibitory factor
The tissue-invasive nematode Onchocerca volvulus causes skin and eye pathology in human onchocerciasis. While the adult females reside sessile in subcutaneous nodules, the microfilariae are abundantly released from the nodules, males and... more
The tissue-invasive nematode Onchocerca volvulus causes skin and eye pathology in human onchocerciasis. While the adult females reside sessile in subcutaneous nodules, the microfilariae are abundantly released from the nodules, males and juvenile worms migrate through the host tissue. Matrix-degrading metallo- and serine proteinases have been detected in excretory-secretory worm products that may be essential for migration of the mobile stages. In this study, a 1713bp long cDNA encoding for a putative proteinase of O. volvulus has been isolated. The predicted protein sequence includes a signal peptide indicating secretion to the extracellular space, a propeptide, an astacin-like protease domain, an EGF-like and a CUB-domain, thereby identifying the protein as a member of the astacin family of zinc endopeptidases. Onchoastacin, Ov-AST-1, is most closely related to a subfamily comprising nematode astacins including Caenorhabditis and Ancylostoma. Ov-AST-1 was expressed as a recombinant protein in baculovirus-infected insect cells and exhibited enzymatic activity. The exposure of onchoastacin to the host immune system is indicated by demonstration of IgG reacting with the recombinant Ov-AST-1 and with two peptides of the protein. Since a homologous metalloproteinase is part of a promising hookworm vaccine, Ov-AST-1 may be a candidate for intervention strategies in filarial infections.
Research Interests: Microbiology, Immunology, Medical Microbiology, Biology, Phylogeny, and 15 moreIdentification, Humans, Microbes, Animals, Metalloproteinase, Protein Sequence Analysis, Immune system, SIGNAL PEPTIDE, Amino Acid Sequence, Base Sequence, Growth Factor, Recombinant Protein, Enzymatic Activity, Onchocerciasis, and Molecular Sequence Data
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Research Interests: Parasitology, Medical Microbiology, Biology, Medicine, Biological Sciences, and 13 moreHumans, Animals, Polymerase Chain Reaction, Rats, Strongyloides Stercoralis, Larva, Wistar Rats, Sensitivity and Specificity, Strongyloidiasis, Medical, Reference standards, Strongyloides, and Medical and Health Sciences
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More than 150 million humans in tropical countries are infected by filarial nematodes which harbor intracellular bacterial endosymbionts of the genus Wolbachia (Rickettsiales). These bacteria have been implicated in adverse effects of... more
More than 150 million humans in tropical countries are infected by filarial nematodes which harbor intracellular bacterial endosymbionts of the genus Wolbachia (Rickettsiales). These bacteria have been implicated in adverse effects of drug treatment in filariasis. The present study provides evidence that purified major Wolbachia surface protein (rWSP) acts as an inducer of the innate immune system through TLR2 and TLR4: 1) recombinant, stringently purified rWSP elicited the release of TNF-α, IL-12, and IL-8 from cultured blood cells of both Onchocerca volvulus-infected and uninfected people; 2) the inflammatory response to rWSP challenge was TLR2- and TLR4-dependent as demonstrated with TLR-transfected fibroblastoid cells, as well as macrophages and dendritic cells from functional TLR-deficient mice; 3) blood cells of onchocerciasis patients exposed to rWSP also generated down-regulating mediators IL-10 and PGE2 after 6 days of culture; 4) furthermore, rWSP-reactive IgG1 Abs were pr...
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Onchocerca volvulus is a human pathogenic filarial parasite which, like other parasitic nematodes, is capable of surviving in an immunologically competent host by employing a variety of immune evasion strategies and defense mechanisms... more
Onchocerca volvulus is a human pathogenic filarial parasite which, like other parasitic nematodes, is capable of surviving in an immunologically competent host by employing a variety of immune evasion strategies and defense mechanisms including the detoxification and repair mechanisms of the glutathione S -transferases (GSTs). In this study we analyzed the glycosylation pattern and the immunological properties of extracellular O. volvulus GST1a and -1b ( Ov GST1a and -1b). The enzymes differ in only 10 amino acids, and both are glycoproteins that have cleavable signal peptides and unusual N-terminal extensions. These characteristics have not been described for other GSTs so far. Mass spectrometry analyses indicate that both enzymes carry high-mannose type oligosaccharides on at least four glycosylation sites. Glycosylation sites 1 to 3 of Ov GST1a ( Ov GST1b sites 2 to 4) are occupied by truncated N-glycans (Man 2 GlcNAc2 to Man 5 GlcNAc 2 ), and N glycosylation site 4 of Ov GST1a (...
Research Interests: Biology, Biological Sciences, Female, Animals, Fauna, and 15 moreGlutathione, Detoxification, Glycoproteins, Enzyme, Glycosylation, Antibody, Amino Acid Profile, Glutathione Transferase, Amino Acid Sequence, Enzyme Linked Immunosorbent Assay, Extracellular, Antigen, Carbohydrate Sequence, Antibody Response, and Host
Research Interests: Immunology, Biology, Medicine, Biological Sciences, Serology, and 15 moreHumans, Lymphatic Filariasis, Animals, Antibody, Filariasis, Mass Drug Administration, Sensitivity and Specificity, Clinical Signs, Recombinant Proteins, Laboratory Tests, Enzyme Linked Immunosorbent Assay, Antigen, DIETHYLCARBAMAZINE, immunoglobulin G, and Medical and Health Sciences
Research Interests: Nonparametric Statistics, Biology, Medicine, Multidisciplinary, Molecular and cellular biology, and 15 moreFemale, Animals, Male, Developmental, Intestines, Protease Inhibitors, Larva, DDC, Medizin, Amino Acid Sequence, Base Sequence, Proteases, Culture Media, Gene Expression Regulation, and Molecular Sequence Data
Deworming is rightly advocated to prevent helminth-induced morbidity. Nevertheless, in affl uent countries, the deliberate infection of patients with worms is being explored as a possible treatment for infl ammatory diseases. Several... more
Deworming is rightly advocated to prevent helminth-induced morbidity. Nevertheless, in affl uent countries, the deliberate infection of patients with worms is being explored as a possible treatment for infl ammatory diseases. Several clinical trials are currently registered, for example, to assess the safety or effi cacy of Trichuris suis ova in allergies, infl ammatory bowel diseases, multiple sclerosis, rheumatoid arthritis, psoriasis, and autism, and the Necator americanus larvae for allergic rhinitis, asthma, coeliac disease, and multiple sclerosis. Studies in animals provide strong evidence that helminths can not only downregulate parasite-specifi c immune responses, but also modulate autoimmune and allergic infl ammatory responses and improve metabolic homoeostasis. This fi nding suggests that deworming could lead to the emergence of infl ammatory and metabolic conditions in countries that are not prepared for these new epidemics. Further studies in endemic countries are needed to assess this risk and to enhance understanding of how helminths modulate infl ammatory and metabolic pathways. Studies are similarly needed in non-endemic countries to move helminth-related interventions that show promise in animals, and in phase 1 and 2 studies in human beings, into the therapeutic development pipeline.