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Mbah GE, Ayiseh RB, Monya E, Ndi EM, Njotu FN, Kulu TK, Sakanari J, Lustigman S, Cho-Ngwa F. Differential susceptibility of Onchocerca ochengi adult male worms to flubendazole in gerbils and hamsters. Parasitol Res 2024; 123:186. [PMID: 38634933 DOI: 10.1007/s00436-024-08207-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 04/09/2024] [Indexed: 04/19/2024]
Abstract
Onchocerciasis is a devastating skin and eye disease that afflicts about 21 million people, most of whom live in sub-Saharan Africa. Its control with the microfilaricidal drug ivermectin is limited, thus necessitating the development of preclinical animal models to aid in the discovery of a macrofilaricide. Previously, we found that Onchocerca ochengi (the closest relative of the human O. volvulus) worm masses survive better in hamsters than in gerbils. The aim of this study was to compare the survival of O. ochengi adult male worms and their susceptibility to flubendazole (FBZ, a macrofilaricide) in gerbils and hamsters. The animals were intraperitoneally implanted with O. ochengi male worms, treated with FBZ, and sacrificed 35 days post-implantation. Unlike gerbils which had some worms moving freely in the peritoneum and some in newly formed nodules (neo-nodules), all the worms in the hamsters were found in neo-nodules. FBZ significantly decreased worm burden, motility, and viability in gerbils whereas it had no significant effect in hamsters. These results highlight a major difference in how O. ochengi adult male worms are sustained and affected by FBZ in gerbils compared to hamsters. Understanding the difference between these two models is important in the development of effective macrofilaricides for onchocerciasis.
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Affiliation(s)
- Glory Enjong Mbah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
- Department of Biology, Higher Teacher Training College (HTTC), The University of Bamenda, Bamenda, Cameroon
- National Higher Polytechnic Institute (NAHPI), The University of Bamenda, Bamenda, Cameroon
| | - Rene Bilingwe Ayiseh
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon.
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon.
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Emmanuel Menang Ndi
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Fabrice Ngoh Njotu
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Tessy-Koko Kulu
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Judy Sakanari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Sara Lustigman
- New York Blood Center, Lindsley F. Kimball Research Institute, New York City, NY, USA
| | - Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon.
- National Higher Polytechnic Institute (NAHPI), The University of Bamenda, Bamenda, Cameroon.
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Zoonotic Implications of Onchocerca Species on Human Health. Pathogens 2020; 9:pathogens9090761. [PMID: 32957647 PMCID: PMC7560048 DOI: 10.3390/pathogens9090761] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 12/14/2022] Open
Abstract
The genus Onchocerca includes several species associated with ungulates as hosts, although some have been identified in canids, felids, and humans. Onchocerca species have a wide geographical distribution, and the disease they produce, onchocerciasis, is generally seen in adult individuals because of its large prepatency period. In recent years, Onchocerca species infecting animals have been found as subcutaneous nodules or invading the ocular tissues of humans; the species involved are O. lupi, O. dewittei japonica, O. jakutensis, O. gutturosa, and O. cervicalis. These findings generally involve immature adult female worms, with no evidence of being fertile. However, a few cases with fertile O. lupi, O. dewittei japonica, and O. jakutensis worms have been identified recently in humans. These are relevant because they indicate that the parasite’s life cycle was completed in the new host—humans. In this work, we discuss the establishment of zoonotic Onchocerca infections in humans, and the possibility of these infections to produce symptoms similar to human onchocerciasis, such as dermatitis, ocular damage, and epilepsy. Zoonotic onchocerciasis is thought to be an emerging human parasitic disease, with the need to take measures such as One Health Strategies, in order to identify and control new cases in humans.
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Boijsen B, Uhlhorn H, Ågren E, Höglund J. Nodular onchocercosis in red deer (Cervus elaphus) in Sweden. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2017; 6:340-343. [PMID: 29034165 PMCID: PMC5636018 DOI: 10.1016/j.ijppaw.2017.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/05/2017] [Accepted: 09/13/2017] [Indexed: 11/27/2022]
Abstract
The presence of subcutaneous nodular onchocercosis was investigated at slaughter of 151 red deer (Cervus elaphus) (107 juveniles and 44 adults) between October–December 2015. The prevalence of subcutaneous nodules was 56%. Nodules were located in the lumbar region of the back in 96% of the cases, and 38% of the infected red deer had additional parasitic nodules in other body locations, such as rump, thorax, forelimbs and neck. The number of nodules per deer was 1–10 in two-thirds of the affected animals, and only 2% had more than 50 nodules. Significant differences in prevalence of nodule presence were found between adult (81%) and juvenile red deer less than two years of age (45%) (p = 0.0001). Species confirmation and identification was done on 14 randomly selected nodules taken from the lumbar region of 14 deer of different geographical origin, by sequencing the mitochondrial 12S, 16S and nad5 gene fragments. The sequences were more or less identical (12S = 99–100%; 16S = 93–100%; nad5 = 92–100%) to previously published sequences for Onchocerca flexuosa. The high prevalence of nodular onchocercosis caused by O. flexuosa in red deer in Sweden shows that the investigated areas in the southern third of Sweden have favorable vector (simuliids and ceratopogonids) conditions and suitable environment for the maintenance of the parasite. To our knowledge, this is the first systematic study of O. flexuosa in red deer in Sweden. Over 50% of the red deer in the study were infected by nodular onchocercosis. Identification of parasite Onchocerca flexuosa by sequencing of mitochondrial fragments 12S, 16S and nad5. Prevalence of nodular onchocercosis was significantly higher in adult red deer than juveniles. The subcutaneous nodules were especially localized to the lumbar region.
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Affiliation(s)
- Bim Boijsen
- Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Box 7036, 75007 Uppsala, Sweden
| | - Henrik Uhlhorn
- National Veterinary Institute, Department of Pathology and Wildlife Diseases, 751 89 Uppsala, Sweden
| | - Erik Ågren
- National Veterinary Institute, Department of Pathology and Wildlife Diseases, 751 89 Uppsala, Sweden
| | - Johan Höglund
- Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Box 7036, 75007 Uppsala, Sweden
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Wolbachia endosymbionts induce neutrophil extracellular trap formation in human onchocerciasis. Sci Rep 2016; 6:35559. [PMID: 27752109 PMCID: PMC5067710 DOI: 10.1038/srep35559] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 10/03/2016] [Indexed: 12/12/2022] Open
Abstract
The endosymbiotic bacteria, Wolbachia, induce neutrophilic responses to the human helminth pathogen Onchocerca volvulus. The formation of Neutrophil Extracellular Traps (NETs), has been implicated in anti-microbial defence, but has not been identified in human helminth infection. Here, we demonstrate NETs formation in human onchocerciasis. Extracellular NETs and neutrophils were visualised around O. volvulus in nodules excised from untreated patients but not in nodules from patients treated with the anti-Wolbachia drug, doxycycline. Whole Wolbachia or microspheres coated with a synthetic Wolbachia lipopeptide (WoLP) of the major nematode Wolbachia TLR2/6 ligand, peptidoglycan associated lipoprotein, induced NETosis in human neutrophils in vitro. TLR6 dependency of Wolbachia and WoLP NETosis was demonstrated using purified neutrophils from TLR6 deficient mice. Thus, we demonstrate for the first time that NETosis occurs during natural human helminth infection and demonstrate a mechanism of NETosis induction via Wolbachia endobacteria and direct ligation of Wolbachia lipoprotein by neutrophil TLR2/6.
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25 Years of the Onchocerca ochengi Model. Trends Parasitol 2016; 32:966-978. [PMID: 27665524 DOI: 10.1016/j.pt.2016.08.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/20/2016] [Accepted: 08/30/2016] [Indexed: 01/12/2023]
Abstract
Although of limited veterinary significance, Onchocerca ochengi has become famous as a natural model or 'analogue' of human onchocerciasis (river blindness), which is caused by Onchocerca volvulus. On the basis of both morphological and molecular criteria, O. ochengi is the closest extant relative of O. volvulus and shares several key natural history traits with the human pathogen. These include exploitation of the same group of insect vectors (blackflies of the Simulium damnosum complex) and formation of collagenous nodules with a similar histological structure to human nodules. Here, we review the contribution of this natural system to drug and vaccine discovery efforts, as well as to our basic biological understanding of Onchocerca spp., over the past quarter-century.
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Mbah GE, Ayiseh RB, Cho-Ngwa F. Development and validation of an Onchocerca ochengi microfilarial hamster model for onchocerciasis drug screens. BMC Infect Dis 2016; 16:404. [PMID: 27515037 PMCID: PMC4982420 DOI: 10.1186/s12879-016-1753-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 08/04/2016] [Indexed: 12/02/2022] Open
Abstract
Background Onchocerciasis, caused by the parasitic nematode, Onchocerca volvulus afflicts some 37 million people worldwide, and is the second leading infectious cause of blindness globally. The only currently recommended drug for treatment of the disease, ivermectin, is only microfilaricidal and has serious adverse effects in individuals co-infected with high loads of Loa loa microfilariae (mf), prompting the search for new and better drugs. Onchocerciasis drug discovery studies have so far been based on in vivo models using Onchocerca species which are not the closest to O. volvulus, and which may therefore, not adequately mimic the natural infection in humans. Therefore, this study was carried out to develop a better drug screening model for onchocerciasis, based on the use of cow-derived O. ochengi, the closest known relative of O. volvulus. Methods Mf of O. ochengi were injected subcutaneously at the nape of Syrian hamsters (Mesocricetus auratus) and BALB/c mice. The skin, and especially the earlobes of the animals were examined for mf 15–31 days after infection. For selected model validation, the hamsters were treated with ivermectin at 150 or 600 μg/kg body weight and examined 30 days after infection for mf. For L. loa studies in hamsters, isolated mf were injected intraperitoneally and animal organs were examined on day 26 for mf. Results The Syrian hamsters were found to be the more permissive to O. ochengi mf as fully viable mf were recovered from them on day 30, compared to BALB/c mice where such mf were recovered on day 15, but not 30. However, both animals were not permissive to L. loa mf even by day 15. Interestingly, more than 50 % of the total O. ochengi mf recovered were from the earlobes. The number of mf injected was directly proportional to the number recovered. Ivermectin at both concentrations tested completely eliminated the O. ochengi mf from the hamsters. Conclusion This study reveals the Syrian hamster as an appropriate small animal model for screening of novel compounds against O. ochengi, the closest known relative of O. volvulus.
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Affiliation(s)
- Glory Enjong Mbah
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, South West Region, Cameroon
| | - Rene Bilingwe Ayiseh
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, South West Region, Cameroon
| | - Fidelis Cho-Ngwa
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, South West Region, Cameroon.
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Tamarozzi F, Wright HL, Johnston KL, Edwards SW, Turner JD, Taylor MJ. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro. Parasite Immunol 2014; 36:494-502. [PMID: 24909063 PMCID: PMC4282327 DOI: 10.1111/pim.12122] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/03/2014] [Indexed: 02/04/2023]
Abstract
The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism.
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Affiliation(s)
- F Tamarozzi
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
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Levels of infection, pathology and nodule size of Onchocerca flexuosa (Nematoda: Onchocercidae) in red deer (Cervus elaphus) from northern Spain. J Helminthol 2014; 89:326-34. [PMID: 24622346 DOI: 10.1017/s0022149x1400011x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Between 2005 and 2007, the presence of Onchocerca flexuosa (Wedl, 1856) was discovered and investigated in 110 red deer (Cervus elaphus) shot in the Riaño Regional Hunting Reserve, in the province of León (north-western Spain). Nodules containing O. flexuosa were located in the dorsal region and flanks of the deer. These were collected and measured, and some adult parasites were extracted from the nodules and identified by morphology and by obtaining mitochondrial 12S rDNA sequences, which were identical to those of previously published sequences for O. flexuosa. Some nodules were prepared for histology, embedded in paraffin, sectioned and stained with haematoxylin-eosin. Histologically, the worms were found in several compartments separated by an infiltrated fibrous tissue. These compartments were inhabited by several females and males, surrounded by a fibrous capsule. A total of 85.45% (95% confidence interval (CI): 78.86-92.04%) of red deer were parasitized, with a mean intensity of 9.53 ± 12.27 nodules/host, ranging between 1 and 74 nodules/deer. Significant differences in prevalence and intensity of infection were found between young and adult red deer, and also between seasons. However, no significant differences between males and females were observed. Five hundred and ninety-seven nodules were measured (15.81 ± 3.94 mm) and classified by sizes into small ( < 10 mm), medium (10-20 mm) and large (>20 mm). No relation was found between the size of the nodules and the time of infection. The high values found in the studied parameters show that northern Spain is an area of high-intensity infection for deer.
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Verocai GG, Lejeune M, Beckmen KB, Kashivakura CK, Veitch AM, Popko RA, Fuentealba C, Hoberg EP, Kutz SJ. Defining parasite biodiversity at high latitudes of North America: new host and geographic records for Onchocerca cervipedis (Nematoda: Onchocercidae) in moose and caribou. Parasit Vectors 2012; 5:242. [PMID: 23110962 PMCID: PMC3507900 DOI: 10.1186/1756-3305-5-242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 10/15/2012] [Indexed: 11/13/2022] Open
Abstract
Background Onchocerca cervipedis is a filarioid nematode of cervids reported from Central America to boreal regions of North America. It is found primarily in subcutaneous tissues of the legs, and is more commonly known as ‘legworm’. Blackflies are intermediate hosts and transmit larvae to ungulates when they blood-feed. In this article we report the first records of O. cervipedis from high latitudes of North America and its occurrence in previously unrecognized host subspecies including the Yukon-Alaska moose (Alces americanus gigas) and the Grant’s caribou (Rangifer tarandus granti). Methods We examined the subcutaneous connective tissues of the metacarpi and/or metatarsi of 34 moose and one caribou for parasitic lesions. Samples were collected from animals killed by subsistence hunters or animals found dead in the Northwest Territories (NT), Canada and Alaska (AK), USA from 2005 to 2012. Genomic DNA lysate was prepared from nematode fragments collected from two moose. The nd5 region of the mitochondrial DNA was amplified by PCR and sequenced. Results Subcutaneous nodules were found in 12 moose from the NT and AK, and one caribou from AK. Nematodes dissected from the lesions were identified as Onchocerca cervipedis based on morphology of female and male specimens. Histopathological findings in moose included cavitating lesions with multifocal granulomatous cellulitis containing intralesional microfilariae and adults, often necrotic and partially mineralized. Lesions in the caribou included periosteitis with chronic cellulitis, eosinophilic and lymphoplasmacytic infiltrate, and abundant granulation associated with intralesional adult nematodes and larvae. Sequences of the nd5 region (471bp), the first generated for this species, were deposited with Genbank (JN580791 and JN580792). Representative voucher specimens were deposited in the archives of the United States National Parasite Collection. Conclusions The geographic range of O. cervipedis is broader than previously thought, and extends into subarctic regions of western North America, at least to latitude 66°N. The host range is now recognized to include two additional subspecies: the Yukon-Alaska moose and Grant’s caribou. Accelerated climate change at high latitudes may affect vector dynamics, and consequently the abundance and distribution of O. cervipedis in moose and caribou. Disease outbreaks and mortality events associated with climatic perturbations have been reported for other filarioids, such as Setaria tundra in Fennoscandia, and may become an emerging issue for O. cervipedis in subarctic North America.
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Affiliation(s)
- Guilherme G Verocai
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
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Kim JS, Kroin JS, Li X, An HS, Buvanendran A, Yan D, Tuman KJ, van Wijnen AJ, Chen D, Im HJ. The rat intervertebral disk degeneration pain model: relationships between biological and structural alterations and pain. Arthritis Res Ther 2011; 13:R165. [PMID: 21996269 PMCID: PMC3308099 DOI: 10.1186/ar3485] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 06/09/2011] [Accepted: 10/13/2011] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Degeneration of the interverterbral disk is as a cause of low-back pain is increasing. To gain insight into relationships between biological processes, structural alterations and behavioral pain, we created an animal model in rats. METHODS Disk degeneration was induced by removal of the nucleus pulposus (NP) from the lumbar disks (L4/L5 and L5/L6) of Sprague Dawley rats using a 0.5-mm-diameter microsurgical drill. The degree of primary hyperalgesia was assessed by using an algometer to measure pain upon external pressure on injured lumbar disks. Biochemical and histological assessments and radiographs of injured disks were used for evaluation. We investigated therapeutic modulation of chronic pain by administering pharmaceutical drugs in this animal model. RESULTS After removal of the NP, pressure hyperalgesia developed over the lower back. Nine weeks after surgery we observed damaged or degenerated disks with proteoglycan loss and narrowing of disk height. These biological and structural changes in disks were closely related to the sustained pain hyperalgesia. A high dose of morphine (6.7 mg/kg) resulted in effective pain relief. However, high doses of pregabalin (20 mg/kg), a drug that has been used for treatment of chronic neuropathic pain, as well as the anti-inflammatory drugs celecoxib (50 mg/kg; a selective inhibitor of cyclooxygenase 2 (COX-2)) and ketorolac (20 mg/kg; an inhibitor of COX-1 and COX-2), did not have significant antihyperalgesic effects in our disk injury animal model. CONCLUSIONS Although similarities in gene expression profiles suggest potential overlap in chronic pain pathways linked to disk injury or neuropathy, drug-testing results suggest that pain pathways linked to these two chronic pain conditions are mechanistically distinct. Our findings provide a foundation for future research on new therapeutic interventions that can lead to improvements in the treatment of patients with back pain due to disk degeneration.
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Affiliation(s)
- Jae-Sung Kim
- Department of Biochemistry, Rush University Medical Center, Cohn Research BD 516, 1735 West Harrison Street, Chicago, IL 60612, USA
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Hansen RDE, Trees AJ, Bah GS, Hetzel U, Martin C, Bain O, Tanya VN, Makepeace BL. A worm's best friend: recruitment of neutrophils by Wolbachia confounds eosinophil degranulation against the filarial nematode Onchocerca ochengi. Proc Biol Sci 2010; 278:2293-302. [PMID: 21177682 PMCID: PMC3119012 DOI: 10.1098/rspb.2010.2367] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Onchocerca ochengi, a filarial parasite of cattle, represents the closest relative of the human pathogen, Onchocerca volvulus. Both species harbour Wolbachia endosymbionts and are remarkable in that adult female worms remain viable but sessile for many years while surrounded by host cells and antibodies. The basis of the symbiosis between filariae and Wolbachia is thought to be metabolic, although a role for Wolbachia in immune evasion has received little attention. Neutrophils are attracted to Wolbachia, but following antibiotic chemotherapy they are replaced by eosinophils that degranulate on the worm cuticle. However, it is unclear whether the eosinophils are involved in parasite killing or if they are attracted secondarily to dying worms. In this study, cattle infected with Onchocerca ochengi received adulticidal regimens of oxytetracycline or melarsomine. In contrast to oxytetracycline, melarsomine did not directly affect Wolbachia viability. Eosinophil degranulation increased significantly only in the oxytetracycline group; whereas nodular gene expression of bovine neutrophilic chemokines was lowest in this group. Moreover, intense eosinophil degranulation was initially associated with worm vitality, not degeneration. Taken together, these data offer strong support for the hypothesis that Wolbachia confers longevity on O. ochengi through a defensive mutualism, which diverts a potentially lethal effector cell response.
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Affiliation(s)
- Rowena D E Hansen
- Liverpool School of Tropical Medicine, School of Veterinary Science and Institute of Infection and Global Health, University of Liverpool, , Liverpool L69 7ZJ, UK
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Neary JM, Trees AJ, Ekale DD, Tanya VN, Hetzel U, Makepeace BL. Onchocerca armillata contains the endosymbiotic bacterium Wolbachia and elicits a limited inflammatory response. Vet Parasitol 2010; 174:267-76. [PMID: 20850932 PMCID: PMC3038270 DOI: 10.1016/j.vetpar.2010.08.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 08/16/2010] [Accepted: 08/23/2010] [Indexed: 11/27/2022]
Abstract
Human onchocerciasis, also known as River Blindness, is a debilitating disease caused by the filarial nematode Onchocerca volvulus. Many, but not all, filarial nematodes carry within their tissues endosymbiotic, Rickettsia-like bacteria of the genus Wolbachia. Onchocerca spp. infections in cattle offer the most relevant, analogous host–parasite model system. West African cattle are commonly co-infected with four Onchocerca spp.; two of these are Wolbachia-positive (Onchocerca gutturosa and Onchocerca ochengi), and the remainder are of unknown Wolbachia status (Onchocerca dukei and Onchocerca armillata). Previous studies have suggested that worm survival is dependent on this bacterium. O. armillata, an abundant parasite of African cattle that has received little attention, is a primitive species that may lack Wolbachia. The objectives of this study were to determine if O. armillata carries Wolbachia and to provide preliminary descriptions of the host inflammatory cell environment around the adult worms. The findings may support or refute the hypothesis that a prime contribution of Wolbachia is to permit long-term survival and reproduction of certain Onchocerca spp. (including O. volvulus in humans). O. armillata adult worms were found in the aorta of 90.7% of cattle (n = 54) slaughtered at an abattoir in Ngaoundéré, Adamawa Region, Cameroon. The presence of Wolbachia in O. armillata was confirmed by a specific anti-Wolbachia surface protein antibody detected using a peroxidase conjugate (immunohistochemistry) and PCR for detection of Wolbachia-specific sequences within DNA extracts from frozen worms. Tissue sections stained with haematoxylin and eosin showed the host cell response to be dominated by macrophages and fibroblasts. This is unusual compared with nodule-dwelling Wolbachia-positive Onchocerca spp., where the host response is typically characterised by granulocytes, and suggests that the mechanisms for worm survival employed by this species (which is probably motile) may differ.
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Affiliation(s)
- Joseph M Neary
- Liverpool School of Tropical Medicine and Faculty of Veterinary Science, University of Liverpool, Liverpool, UK
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Attout T, Hoerauf A, Dénécé G, Debrah AY, Marfo-Debrekyei Y, Boussinesq M, Wanji S, Martinez V, Mand S, Adjei O, Bain O, Specht S, Martin C. Lymphatic vascularisation and involvement of Lyve-1+ macrophages in the human onchocerca nodule. PLoS One 2009; 4:e8234. [PMID: 20011036 PMCID: PMC2784295 DOI: 10.1371/journal.pone.0008234] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 10/03/2009] [Indexed: 12/30/2022] Open
Abstract
Onchocerciasis, caused by the filarial nematode Onchocerca volvulus, is a parasitic disease leading to debilitating skin disease and blindness, with major economic and social consequences. The pathology of onchocerciasis is principally considered to be a consequence of long-standing host inflammatory responses. In onchocerciasis a subcutaneous nodule is formed around the female worms, the core of which is a dense infiltrate of inflammatory cells in which microfilariae are released. It has been established that the formation of nodules is associated with angiogenesis. In this study, we show using specific markers of endothelium (CD31) and lymphatic endothelial cells (Lyve-1, Podoplanin) that not only angiogenesis but also lymphangiogenesis occurs within the nodule. 7% of the microfilariae could be found within the lymphatics, but none within blood vessels in these nodules, suggesting a possible route of migration for the larvae. The neovascularisation was associated with a particular pattern of angio/lymphangiogenic factors in nodules of onchocerciasis patients, characterized by the expression of CXCL12, CXCR4, VEGF-C, Angiopoietin-1 and Angiopoietin-2. Interestingly, a proportion of macrophages were found to be positive for Lyve-1 and some were integrated into the endothelium of the lymphatic vessels, revealing their plasticity in the nodular micro-environment. These results indicate that lymphatic as well as blood vascularization is induced around O. volvulus worms, either by the parasite itself, e.g. by the release of angiogenic and lymphangiogenic factors, or by consecutive host immune responses.
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Affiliation(s)
- Tarik Attout
- USM 307, Parasitologie comparée et Modèles expérimentaux, Muséum National d'Histoire Naturelle, Paris, France
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Clinic Bonn, Bonn, Germany
| | - Gaëlle Dénécé
- USM 307, Parasitologie comparée et Modèles expérimentaux, Muséum National d'Histoire Naturelle, Paris, France
| | - Alexander Yaw Debrah
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | | | | | - Samuel Wanji
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
- Department of Biochemistry and Microbiology, University of Buea, Buea, Cameroon
| | - Valérie Martinez
- Service de Médecine Interne et Immunologie Clinique, Hôpital Antoine Béclère, Clamart, France
| | - Sabine Mand
- Institute for Medical Microbiology, Immunology and Parasitology, University Clinic Bonn, Bonn, Germany
| | - Ohene Adjei
- Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
| | - Odile Bain
- USM 307, Parasitologie comparée et Modèles expérimentaux, Muséum National d'Histoire Naturelle, Paris, France
| | - Sabine Specht
- Institute for Medical Microbiology, Immunology and Parasitology, University Clinic Bonn, Bonn, Germany
| | - Coralie Martin
- USM 307, Parasitologie comparée et Modèles expérimentaux, Muséum National d'Histoire Naturelle, Paris, France
- * E-mail:
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14
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Cutaneous Onchocerciasis: Immunohistochemical Detection of Mast Cell Population. Appl Immunohistochem Mol Morphol 2009; 17:88-91. [DOI: 10.1097/pai.0b013e31817738aa] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Chirgwin SR, Rao UR, Coleman SU, Nowling JM, Klei TR. Profiling the cellular immune response to multiple Brugia pahangi infections in a susceptible host. J Parasitol 2006; 91:822-9. [PMID: 17089749 DOI: 10.1645/ge-400r.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Human lymphatic filariasis is caused primarily by Brugia malayi and Wuchereria bancroffi. Unraveling this disease is complex, as people living in endemic areas exhibit a vast array of clinical states and immune responses. The Mongolian gerbil (Meriones unguiculatus)-B. pahangi model of human lymphatic filariasis has provided much information on immune parameters associated with filarial infection. Prior investigations in our laboratory have shown that gerbils closely mimic a subset of patients classified as microfilaremic but asymptomatic, a group that comprises the majority of people living in endemic areas. Worm recovery data suggest that gerbils carrying current B. pahangi infections do not show any resistance to subsequent subcutaneous B. pahangi infections. The aim of the present studies was to investigate the T cell cytokine response in gerbils receiving multiple infections of B. pahangi as a means of mimicking the conditions experienced by people in endemic areas. The T cell cytokine profile generated by multiply infected gerbils was not different from that previously generated by gerbils infected only once with B. pahangi. Gerbils infected multiple times with B. pahangi showed a transient increase in IL-5, which corresponded to the increased eosinophil levels previously reported from multiply infected gerbils. Chronically infected gerbils showed elevated IL-4 mRNA levels, as has been reported from gerbils infected only once with B. pahangi. Chronic infections were also associated with a state of immune hyporesponsiveness, as determined by the characterization of lymphatic thrombi and lymphoproliferation of spleen and renal lymph node cells to worm antigen.
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Affiliation(s)
- S R Chirgwin
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana 70803, USA
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16
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Nfon CK, Makepeace BL, Njongmeta LM, Tanya VN, Bain O, Trees AJ. Eosinophils contribute to killing of adult Onchocerca ochengi within onchocercomata following elimination of Wolbachia. Microbes Infect 2006; 8:2698-705. [PMID: 16962357 DOI: 10.1016/j.micinf.2006.07.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 07/26/2006] [Accepted: 07/27/2006] [Indexed: 11/25/2022]
Abstract
Many filarial nematodes, including Onchocerca volvulus (the cause of human 'River Blindness'), have a mutually dependent relationship with Wolbachia bacteria. There has been much interest in Wolbachia as a chemotherapeutic target, since there are no macrofilaricidal drugs (i.e., lethal to adult worms) of low toxicity. Using the bovine parasite O. ochengi, we previously demonstrated that combined intensive and intermittent (COM) oxytetracycline treatment induces a sustained depletion of Wolbachia and is macrofilaricidal, whereas a short intensive regimen (SIR) is non-macrofilaricidal. To understand how targeting Wolbachia with oxytetracycline can lead to worm death, O. ochengi nodules (onchocercomata) were sequentially excised from cattle administered COM or SIR therapy, and cell infiltrates were microscopically quantified. Pre-treatment, worms were surrounded by neutrophils, with eosinophils rare or absent. At 8-12weeks after either regimen, eosinophils increased around worms and were observed degranulating on the cuticle. However, with the SIR treatment, neutrophils returned to predominance by 48weeks, while in the COM group, eosinophilia persisted. These observations suggest that accumulation of degranulating eosinophils over a prolonged period is a cause rather than an effect of parasite death, and the macrofilaricidal mechanism of antibiotics may relate to facilitation of eosinophil infiltration around worms by ablation of Wolbachia-mediated neutrophilia.
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Affiliation(s)
- Charles K Nfon
- Liverpool School of Tropical Medicine and Faculty of Veterinary Science, University of Liverpool, Pembroke Place, Liverpool L3 5QA, UK
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17
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Beytut E, Akca A, Bain O. Teat onchocercosis in cows with reference to prevalence, species involved and pathology. Res Vet Sci 2005; 78:45-51. [PMID: 15500839 DOI: 10.1016/j.rvsc.2004.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2004] [Indexed: 11/29/2022]
Abstract
The present study reports teat onchocercosis in cows in the province of Kars in north eastern Turkey with reference to the prevalence, species involved and pathological findings. In the study, 600 cows of various breeds and ages slaughtered in the local abattoir were examined and 145 (24%) were found to have various lesions on their teats, of which 45 (31%) were infected with three Onchocerca species (Onchocerca gutturosa, O. lienalis and an unidentified Onchocerca spp.), identified according to their morphological characteristics. Gross pathological examination of the teats with lesions revealed scabies and chaps of varying sizes, healed sores and small nodules. Histopathologically, large numbers of microfilariae were commonly observed within the collagenous fibre bundles of the dermis, with only a few microfilariae in the dermis in some cases. The microfilariae were also often found to have accumulated around the perivascular spaces and were frequently associated with infiltration by inflammatory cells, predominantly eosinophil leukocytes and mononuclear cells. In two cases, microfilariae were discovered exclusively in the lumen of the capillaries of the dermal papillaries. In one case, in which microfilarae were not encountered, sections of adult worms surrounded by neutrophil leukocytes were detected free in the teat canal. The presence of extensive teat lesions along with microfilariae of the Onchocerca species as found in this study warrants further assessment of the impact of onchocercosis on dairy farming.
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Affiliation(s)
- E Beytut
- Department of Pathology, University of Kafkas, Kars, Turkey.
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18
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Saeftel M, Arndt M, Specht S, Volkmann L, Hoerauf A. Synergism of gamma interferon and interleukin-5 in the control of murine filariasis. Infect Immun 2004; 71:6978-85. [PMID: 14638787 PMCID: PMC308906 DOI: 10.1128/iai.71.12.6978-6985.2003] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There has been a prevailing perception that Th1 and Th2 immune responses induce antagonistic immune effector mechanisms during an infection. We investigated the role of the Th1 cytokine gamma interferon (IFN-gamma) and the Th2 cytokine interleukin-5 (IL-5) in murine filariasis infections with the rodent filarial nematode Litomosoides sigmodontis with regard to immune responses to the parasite. Earlier data showed an important role for IL-5 and IFN-gamma in effective immune responses to filarial infection. Therefore, in this study it was asked whether IL-5 and IFN-gamma act synergistically or antagonistically. Indeed, IL-5 as well as IFN-gamma knockout (KO) mice show a higher worm load than the wild-type controls. IFN-gamma/IL-5 double-KO mice had a significantly higher worm load than any of the single-KO mice, suggesting a synergism between IFN-gamma and IL-5 in controlling worm infection. Neutrophils are known to play an important role for the containment and encapsulation process of the worms. In infected IFN-gamma KO, IL-5 KO, and IFN-gamma/IL-5 double-KO mice, neutrophils were significantly reduced in chemotactic activity levels compared to controls. In addition, the level of phagocytosis activity of neutrophils from IFN-gamma/IL-5 double-KO mice was further decreased in comparison to that of the single-KO mice. Levels of tumor necrosis factor alpha, which is an important factor for neutrophil activation, were found to be reduced in macrophages from KO mice. In conclusion, these results argue for immune effector mechanisms in murine filarial infection that are dependent on both IFN-gamma and IL-5. Synergistic effects of the two cytokines may be mediated, at least in part, by neutrophils for the control of adult worms.
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Affiliation(s)
- Michael Saeftel
- Bernhard Nocht Institute for Tropical Medicine, Department of Helminthology, 20359 Hamburg, Germany
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19
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Brattig NW, Büttner DW, Hoerauf A. Neutrophil accumulation around Onchocerca worms and chemotaxis of neutrophils are dependent on Wolbachia endobacteria. Microbes Infect 2001; 3:439-46. [PMID: 11377205 DOI: 10.1016/s1286-4579(01)01399-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Unlike in many other helminth infections, neutrophilic granulocytes are major cellular components in the hosts immune response against filarial worms. The pathways that drive the immune response involving neutrophils are unclear. This study shows that Wolbachia endobacteria (detectable by polyclonal antibodies against endobacterial heat shock protein 60 and catalase and by polymerase chain reaction being sensitive to doxycycline treatment) are direct and indirect sources of signals accounting for neutrophil accumulation around adult Onchocerca volvulus filariae. Worm nodules from untreated onchocerciasis patients displayed a strong neutrophil infiltrate adjacent to the live adult worms. In contrast, in patients treated with doxycycline to eliminate the endobacteria from O. volvulus and to render the worms sterile, the neutrophil accumulation around live adult filariae was drastically reduced. Neutrophils were absent in worm nodules from the deer filaria Onchocerca flexuosa, a species which does not contain endobacteria. Extracts of O. volvulus extirpated from untreated patients showed neutrophil chemotactic activity and in addition, induced strong TNF-alpha and IL-8 production in human monocytes, in contrast to filarial extracts obtained after doxycycline treatment. Thus, neutrophil chemotaxis and activation are induced directly by endobacterial products and also indirectly via chemokine induction by monocytes. These results show that the neutrophil response is a characteristic of endobacteria-containing filariae.
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Affiliation(s)
- N W Brattig
- Department of Clinical Chemistry, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany.
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20
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Saeftel M, Volkmann L, Korten S, Brattig N, Al-Qaoud K, Fleischer B, Hoerauf A. Lack of interferon-γ confers impaired neutrophil granulocyte function and imparts prolonged survival of adult filarial worms in murine filariasis. Microbes Infect 2001; 3:203-13. [PMID: 11358714 DOI: 10.1016/s1286-4579(01)01372-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We investigated the role of IFN-gamma in host defense during murine filariasis. Using the fully permissive infection of BALB/c mice with the rodent filaria Litomosoides sigmodontis, we show that interferon (IFN)-gamma is essential for encapsulation of adult filarial worms in inflammatory nodules and for normal worm clearance. IFN-gamma knockout (KO) mice had only one third of the nodules of wild-type mice but displayed a more than twofold increase in worm burden and increased microfilaremia. Neutrophil granulocytes, but not macrophages or eosinophils, appear to directly control worm load and nodule formation. Neutrophils, which we showed earlier to be essential for the encapsulation process in the thoracic cavity, where the worms reside, were diminished at this location in IFN-gamma KO compared to wild-type mice; they also displayed strongly reduced chemotactic and phagocytic activity compared to neutrophils of controls. This argues for a distinct defect in neutrophil activation accounting for the low formation of inflammatory nodules. Tumor necrosis factor-alpha, a major neutrophil-activating cytokine expressed by macrophages in the thoracic cavity around the worms, was highly induced in wild-type but absent in KO mice. Diminished activation of neutrophils seems to be a general hallmark of IFN-gamma KO mice, since neutrophils from uninfected KO mice also showed a reduction in chemotactic and phagocytic activity when induced by casein. In conclusion, these data are the first to define an IFN-gamma-dependent immune effector mechanism in murine filarial infection, i.e. neutrophil-mediated control of the adult worm load.
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Affiliation(s)
- M Saeftel
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
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21
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Al-Qaoud KM, Pearlman E, Hartung T, Klukowski J, Fleischer B, Hoerauf A. A new mechanism for IL-5-dependent helminth control: neutrophil accumulation and neutrophil-mediated worm encapsulation in murine filariasis are abolished in the absence of IL-5. Int Immunol 2000; 12:899-908. [PMID: 10837417 DOI: 10.1093/intimm/12.6.899] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
IL-5 production and eosinophilia are features of helminth infections, but results concerning the role of IL-5 and eosinophils (EP) in worm control are contradictory. We describe here a novel, IL-5-dependent mechanism of helminth control in vivo, using a fully permissive murine filariasis model, i.e. infection of BALB/c mice with Litomosoides sigmodontis. Worm control was exerted by the formation of inflammatory nodules around adult filariae which initially remained alive but were eventually killed within several weeks. The cell population essential for inflammatory nodule formation was found to be neutrophils (NP) but not EP. Neutralization of IL-5 led to a failure of both EP and NP accumulation at the site of infection (i.e. the thoracic cavity), resulting in cessation of inflammatory nodule formation around worms and in their survival. The role of NP in this process was confirmed by treatment of mice with anti-granulocyte colony stimulating factor (G-CSF) which also resulted in a lack of inflammatory nodule formation and worm killing albeit in the presence of EP. Since IL-5, due to the absence of IL-5 receptors on NP, does not act on these cells directly, it was investigated if anti-IL-5 altered the production of NP-chemotactic cytokines. In anti-IL-5-treated mice, cytokines known to promote NP accumulation like tumor necrosis factor-alpha, G-CSF and KC (IL-8) were found to be strongly reduced, while NP-deactivating cytokines like IL-10 were increased. In conclusion, IL-5 constitutes a cytokine essential for NP-mediated worm control in filarial infection.
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Affiliation(s)
- K M Al-Qaoud
- Bernhard-Nocht-Institute of Tropical Medicine, Bernhard-Nocht-Strasse 74, 20359 Hamburg, Germany
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Wildenburg G, Korten S, Mainuka P, Büttner DW. Ivermectin influence on the mast cell activity in nodules of onchocerciasis patients. Trop Med Int Health 1998; 3:918-25. [PMID: 9855406 DOI: 10.1046/j.1365-3156.1998.00326.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Onchocercal nodules were stained immunohistochemically using antibodies specific for human mast cells and IgE to elucidate the localization and frequency of mast cells after a single oral dose of 150 microg/kg ivermectin. Tryptase-and chymase-positive mast cells occurred predominantly in mixed inflammatory infiltrates and perivascularly, and never adhered to adult worms or microfilariae. Up to three days after ivermectin, mast cells and IgE-positive cells were markedly increased in the capsular area of nodules containing female worms with embryos and microfilariae compared to untreated nodules. In the centre of these nodules, around the adult Onchocerca volvulus, we found many tryptase-positive cells. More mast cells were IgE-positive than in untreated nodules, equalling the number of tryptase-positive mast cells. There was a clear correlation between the appearance of mast cells and the attacks on damaged microfilariae by eosinophils and macrophages and in the vicinity of adult worms by neutrophils that occur soon after ivermectin treatment. Onchocercomata harbouring female worms with oocytes only revealed, after all treatment intervals, the same mast cell numbers as untreated nodules. In conclusion, during the first three days after administration, ivermectin produces increased numbers of mast cells in nodules harbouring females with embryos and microfilariae, probably as part of an allergic reaction to the attacked microfilariae. Four to 19 days after ivermectin the number of mast cells in the entire nodule is no longer elevated.
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Affiliation(s)
- G Wildenburg
- Department of Helminthology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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