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An Unbiased Immunization Strategy Results in the Identification of Enolase as a Potential Marker for Nanobody-Based Detection of Trypanosoma evansi. Vaccines (Basel) 2020; 8:vaccines8030415. [PMID: 32722150 PMCID: PMC7565430 DOI: 10.3390/vaccines8030415] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/16/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Trypanosoma evansi is a widely spread parasite that causes the debilitating disease “surra” in several types of ungulates. This severely challenges livestock rearing and heavily weighs on the socio-economic development in the affected areas, which include countries on five continents. Active case finding requires a sensitive and specific diagnostic test. In this paper, we describe the application of an unbiased immunization strategy to identify potential biomarkers for Nanobody (Nb)-based detection of T. evansi infections. Alpaca immunization with soluble lysates from different T. evansi strains followed by panning against T. evansi secretome resulted in the selection of a single Nb (Nb11). By combining Nb11-mediated immuno-capturing with mass spectrometry, the T. evansi target antigen was identified as the glycolytic enzyme enolase. Four additional anti-enolase binders were subsequently generated by immunizing another alpaca with the recombinant target enzyme. Together with Nb11, these binders were evaluated for their potential use in a heterologous sandwich detection format. Three Nb pairs were identified as candidates for the further development of an antigen-based assay for Nb-mediated diagnosis of T. evansi infection.
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Gillis-Germitsch N, Schnyder M. Impact of heat treatment on antigen detection in sera of Angiostrongylus vasorum infected dogs. Parasit Vectors 2017; 10:421. [PMID: 28915846 PMCID: PMC5602946 DOI: 10.1186/s13071-017-2366-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 09/07/2017] [Indexed: 11/30/2022] Open
Abstract
Background In the last decade serological tests for detection of circulating Angiostrongylus vasorum antigen and specific antibodies have been developed and adopted for individual diagnosis and epidemiological studies in dogs. Although confirmed positive at necropsy, antigen detection was not possible in single experimentally, as well as naturally infected dogs, possibly due to immune complex formation. The aim of this study was to evaluate the effect of heat treatment on detection of A. vasorum antigen in sera of experimentally (n = 21, 119 follow-up sera) and naturally (n = 18) infected animals. In addition, sera of dogs showing clinical signs consistent with angiostrongylosis (n = 10), of randomly selected dogs (n = 58) and of dogs with other parasitic infections (n = 15) were evaluated. Sera were subjected to heat treatment at 100 °C after addition of 0.5 M EDTA (dilution 1:5) and tested with ELISAs for detection of circulating A. vasorum antigen before and after treatment. Results Between 5 and 11 weeks post-inoculation (wpi) the percentage of positive untreated samples (experimentally infected dogs) increased over time from 33.3 to 90%. Single samples were still negative between 12 and 15 wpi. Overall, between 5 and 15 wpi, 50.6% (45/89) of the available samples were seropositive. From 3 to 6 wpi EDTA/heat treatment caused a change in 8/34 (23.5%) of the samples, with most (n = 6, 17.6%) converting from positive to negative. In contrast, from 7 to 10 wpi, treatment induced a change in 19/52 (36.5%) samples, with all but one converting from negative to positive. Thirteen of 18 naturally infected dogs were antigen positive before and 15 after EDTA/heat treatment, respectively. Untreated samples of 3 dogs with suspected angiostrongylosis were antigen positive, of which only one remained positive after EDTA/heat treatment. One of 58 untreated random samples was antigen positive; this sample became negative after treatment, while another turned positive. One of 15 dogs infected with other parasites than A. vasorum was positive before but negative after treatment. Conclusion Although heat treatment improves A. vasorum antigen detection between 7 and 10 wpi by immune complex disruption, we do not recommend systematic pretreating sera because of reduced antigen detection between 3 and 6 wpi and impairment of antibody detection, if performed contemporaneously.
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Affiliation(s)
- Nina Gillis-Germitsch
- Institute of Parasitology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 266a, 8057, Zürich, Switzerland
| | - Manuela Schnyder
- Institute of Parasitology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 266a, 8057, Zürich, Switzerland.
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Structural basis for the high specificity of a Trypanosoma congolense immunoassay targeting glycosomal aldolase. PLoS Negl Trop Dis 2017; 11:e0005932. [PMID: 28915239 PMCID: PMC5617235 DOI: 10.1371/journal.pntd.0005932] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 09/27/2017] [Accepted: 09/04/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Animal African trypanosomosis (AAT) is a neglected tropical disease which imposes a heavy burden on the livestock industry in Sub-Saharan Africa. Its causative agents are Trypanosoma parasites, with T. congolense and T. vivax being responsible for the majority of the cases. Recently, we identified a Nanobody (Nb474) that was employed to develop a homologous sandwich ELISA targeting T. congolense fructose-1,6-bisphosphate aldolase (TcoALD). Despite the high sequence identity between trypanosomatid aldolases, the Nb474-based immunoassay is highly specific for T. congolense detection. The results presented in this paper yield insights into the molecular principles underlying the assay's high specificity. METHODOLOGY/PRINCIPAL FINDINGS The structure of the Nb474-TcoALD complex was determined via X-ray crystallography. Together with analytical gel filtration, the structure reveals that a single TcoALD tetramer contains four binding sites for Nb474. Through a comparison with the crystal structures of two other trypanosomatid aldolases, TcoALD residues Ala77 and Leu106 were identified as hot spots for specificity. Via ELISA and surface plasmon resonance (SPR), we demonstrate that mutation of these residues does not abolish TcoALD recognition by Nb474, but does lead to a lack of detection in the Nb474-based homologous sandwich immunoassay. CONCLUSIONS/SIGNIFICANCE The results show that the high specificity of the Nb474-based immunoassay is not determined by the initial recognition event between Nb474 and TcoALD, but rather by its homologous sandwich design. This (i) provides insights into the optimal set-up of the assay, (ii) may be of great significance for field applications as it could explain the potential detection escape of certain T. congolense strains, and (iii) may be of general interest to those developing similar assays.
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Stijlemans B, De Baetselier P, Caljon G, Van Den Abbeele J, Van Ginderachter JA, Magez S. Nanobodies As Tools to Understand, Diagnose, and Treat African Trypanosomiasis. Front Immunol 2017; 8:724. [PMID: 28713367 PMCID: PMC5492476 DOI: 10.3389/fimmu.2017.00724] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 06/08/2017] [Indexed: 02/04/2023] Open
Abstract
African trypanosomes are strictly extracellular protozoan parasites that cause diseases in humans and livestock and significantly affect the economic development of sub-Saharan Africa. Due to an elaborate and efficient (vector)–parasite–host interplay, required to complete their life cycle/transmission, trypanosomes have evolved efficient immune escape mechanisms that manipulate the entire host immune response. So far, not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. Current therapies, however, exhibit high drug toxicity and an increased drug resistance is being reported. In addition, diagnosis is often hampered due to the inadequacy of current diagnostic procedures. In the context of tackling the shortcomings of current treatment and diagnostic approaches, nanobodies (Nbs, derived from the heavy chain-only antibodies of camels and llamas) might represent unmet advantages compared to conventional tools. Indeed, the combination of their small size, high stability, high affinity, and specificity for their target and tailorability represents a unique advantage, which is reflected by their broad use in basic and clinical research to date. In this article, we will review and discuss (i) diagnostic and therapeutic applications of Nbs that are being evaluated in the context of African trypanosomiasis, (ii) summarize new strategies that are being developed to optimize their potency for advancing their use, and (iii) document on unexpected properties of Nbs, such as inherent trypanolytic activities, that besides opening new therapeutic avenues, might offer new insight in hidden biological activities of conventional antibodies.
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Affiliation(s)
- Benoit Stijlemans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Patrick De Baetselier
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp (UA), Antwerp, Belgium
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium
| | - Jo A Van Ginderachter
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
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5
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Ponte-Sucre A. An Overview of Trypanosoma brucei Infections: An Intense Host-Parasite Interaction. Front Microbiol 2016; 7:2126. [PMID: 28082973 PMCID: PMC5183608 DOI: 10.3389/fmicb.2016.02126] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 12/16/2016] [Indexed: 12/14/2022] Open
Abstract
Trypanosoma brucei rhodesiense and T. brucei gambiense, the causative agents of Human African Trypanosomiasis, are transmitted by tsetse flies. Within the vector, the parasite undergoes through transformations that prepares it to infect the human host. Sequentially these developmental stages are the replicative procyclic (in which the parasite surface is covered by procyclins) and trypo-epimastigote forms, as well as the non-replicative, infective, metacyclic form that develops in the vector salivary glands. As a pre-adaptation to their life in humans, metacyclic parasites begin to express and be densely covered by the Variant Surface Glycoprotein (VSG). Once the metacyclic form invades the human host the parasite develops into the bloodstream form. Herein the VSG triggers a humoral immune response. To avoid this humoral response, and essential for survival while in the bloodstream, the parasite changes its cover periodically and sheds into the surroundings the expressed VSG, thus evading the consequences of the immune system activation. Additionally, tools comparable to quorum sensing are used by the parasite for the successful parasite transmission from human to insect. On the other hand, the human host promotes clearance of the parasite triggering innate and adaptive immune responses and stimulating cytokine and chemokine secretion. All in all, the host–parasite interaction is extremely active and leads to responses that need multiple control sites to develop appropriately.
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Affiliation(s)
- Alicia Ponte-Sucre
- Laboratory of Molecular Physiology, Institute of Experimental Medicine, Luis Razetti School of Medicine, Faculty of Medicine, Universidad Central de Venezuela Caracas, Venezuela
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Mogk S, Boßelmann CM, Mudogo CN, Stein J, Wolburg H, Duszenko M. African trypanosomes and brain infection - the unsolved question. Biol Rev Camb Philos Soc 2016; 92:1675-1687. [PMID: 27739621 DOI: 10.1111/brv.12301] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/07/2016] [Accepted: 09/08/2016] [Indexed: 12/14/2022]
Abstract
African trypanosomes induce sleeping sickness. The parasites are transmitted during the blood meal of a tsetse fly and appear primarily in blood and lymph vessels, before they enter the central nervous system. During the latter stage, trypanosomes induce a deregulation of sleep-wake cycles and some additional neurological disorders. Historically, it was assumed that trypanosomes cross the blood-brain barrier and settle somewhere between the brain cells. The brain, however, is a strictly controlled and immune-privileged area that is completely surrounded by a dense barrier that covers the blood vessels: this is the blood-brain barrier. It is known that some immune cells are able to cross this barrier, but this requires a sophisticated mechanism and highly specific cell-cell interactions that have not been observed for trypanosomes within the mammalian host. Interestingly, trypanosomes injected directly into the brain parenchyma did not induce an infection. Likewise, after an intraperitoneal infection of rats, Trypanosoma brucei brucei was not observed within the brain, but appeared readily within the cerebrospinal fluid (CSF) and the meninges. Therefore, the parasite did not cross the blood-brain barrier, but the blood-CSF barrier, which is formed by the choroid plexus, i.e. the part of the ventricles where CSF is produced from blood. While there is no question that trypanosomes are able to invade the brain to induce a deadly encephalopathy, controversy exists about the pathway involved. This review lists experimental results that support crossing of the blood-brain barrier and of the blood-CSF barrier and discuss the implications that either pathway would have on infection progress and on the survival strategy of the parasite. For reasons discussed below, we prefer the latter pathway and suggest the existence of an additional distinct meningeal stage, from which trypanosomes could invade the brain via the Virchow-Robin space thereby bypassing the blood-brain barrier. We also consider healthy carriers, i.e. people living symptomless with the disease for up to several decades, and discuss implications the proposed meningeal stage would have for new anti-trypanosomal drug development. Considering the re-infection of blood, a process called relapse, we discuss the likely involvement of the newly described glymphatic connection between the meningeal space and the lymphatic system, that seems also be important for other infectious diseases.
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Affiliation(s)
- Stefan Mogk
- Department of Natural Sciences, Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, 72076, Hoppe-Seyler-Str. 4, Germany
| | - Christian M Boßelmann
- Department of Natural Sciences, Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, 72076, Hoppe-Seyler-Str. 4, Germany
| | - Celestin N Mudogo
- Department of Natural Sciences, Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, 72076, Hoppe-Seyler-Str. 4, Germany.,Department of Basic Sciences, School of Medicine, University of Kinshasa, BP 834 KIN XI, Kinshasa, D.R. Congo
| | - Jasmin Stein
- Department of Natural Sciences, Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, 72076, Hoppe-Seyler-Str. 4, Germany
| | - Hartwig Wolburg
- Medical Department, Institute of Pathology and Neuropathology, University of Tübingen, Tübingen, 72076, Liebermeister Str. 8, Germany
| | - Michael Duszenko
- Department of Natural Sciences, Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, 72076, Hoppe-Seyler-Str. 4, Germany.,Medical Department, School of Medicine, Tongji University, 1239 Siping Road, Shanghai, P.R. China
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An Anti-proteome Nanobody Library Approach Yields a Specific Immunoassay for Trypanosoma congolense Diagnosis Targeting Glycosomal Aldolase. PLoS Negl Trop Dis 2016; 10:e0004420. [PMID: 26835967 PMCID: PMC4737498 DOI: 10.1371/journal.pntd.0004420] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 01/11/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Infectious diseases pose a severe worldwide threat to human and livestock health. While early diagnosis could enable prompt preventive interventions, the majority of diseases are found in rural settings where basic laboratory facilities are scarce. Under such field conditions, point-of-care immunoassays provide an appropriate solution for rapid and reliable diagnosis. The limiting steps in the development of the assay are the identification of a suitable target antigen and the selection of appropriate high affinity capture and detection antibodies. To meet these challenges, we describe the development of a Nanobody (Nb)-based antigen detection assay generated from a Nb library directed against the soluble proteome of an infectious agent. In this study, Trypanosoma congolense was chosen as a model system. METHODOLOGY/PRINCIPAL FINDINGS An alpaca was vaccinated with whole-parasite soluble proteome to generate a Nb library from which the most potent T. congolense specific Nb sandwich immunoassay (Nb474H-Nb474B) was selected. First, the Nb474-homologous sandwich ELISA (Nb474-ELISA) was shown to detect experimental infections with high Positive Predictive Value (98%), Sensitivity (87%) and Specificity (94%). Second, it was demonstrated under experimental conditions that the assay serves as test-of-cure after Berenil treatment. Finally, this assay allowed target antigen identification. The latter was independently purified through immuno-capturing from (i) T. congolense soluble proteome, (ii) T. congolense secretome preparation and (iii) sera of T. congolense infected mice. Subsequent mass spectrometry analysis identified the target as T. congolense glycosomal aldolase. CONCLUSIONS/SIGNIFICANCE The results show that glycosomal aldolase is a candidate biomarker for active T. congolense infections. In addition, and by proof-of-principle, the data demonstrate that the Nb strategy devised here offers a unique approach to both diagnostic development and target discovery that could be widely applied to other infectious diseases.
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Transplacental Transmission of Trypanosoma evansi From Experimentally Infected Donkey Mare to Neonatal Foal. J Equine Vet Sci 2015. [DOI: 10.1016/j.jevs.2015.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Mogk S, Meiwes A, Boßelmann CM, Wolburg H, Duszenko M. The lane to the brain: how African trypanosomes invade the CNS. Trends Parasitol 2014; 30:470-7. [DOI: 10.1016/j.pt.2014.08.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/08/2014] [Accepted: 08/08/2014] [Indexed: 12/13/2022]
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Mogk S, Meiwes A, Shtopel S, Schraermeyer U, Lazarus M, Kubata B, Wolburg H, Duszenko M. Cyclical appearance of African trypanosomes in the cerebrospinal fluid: new insights in how trypanosomes enter the CNS. PLoS One 2014; 9:e91372. [PMID: 24618708 PMCID: PMC3950183 DOI: 10.1371/journal.pone.0091372] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 02/09/2014] [Indexed: 11/25/2022] Open
Abstract
It is textbook knowledge that human infective forms of Trypanosoma brucei, the causative agent of sleeping sickness, enter the brain across the blood-brain barrier after an initial phase of weeks (rhodesiense) or months (gambiense) in blood. Based on our results using an animal model, both statements seem questionable. As we and others have shown, the first infection relevant crossing of the blood brain border occurs via the choroid plexus, i.e. via the blood-CSF barrier. In addition, counting trypanosomes in blood-free CSF obtained by an atlanto-occipital access revealed a cyclical infection in CSF that was directly correlated to the trypanosome density in blood infection. We also obtained conclusive evidence of organ infiltration, since parasites were detected in tissues outside the blood vessels in heart, spleen, liver, eye, testis, epididymis, and especially between the cell layers of the pia mater including the Virchow-Robin space. Interestingly, in all organs except pia mater, heart and testis, trypanosomes showed either a more or less degraded appearance of cell integrity by loss of the surface coat (VSG), loss of the microtubular cytoskeleton and loss of the intracellular content, or where taken up by phagocytes and degraded intracellularly within lysosomes. This is also true for trypanosomes placed intrathecally into the brain parenchyma using a stereotactic device. We propose a different model of brain infection that is in accordance with our observations and with well-established facts about the development of sleeping sickness.
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Affiliation(s)
- Stefan Mogk
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Andreas Meiwes
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Swetlana Shtopel
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | | | - Michael Lazarus
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | | | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, University of Tübingen, Tübingen, Germany
| | - Michael Duszenko
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
- Faculty of Medicine and Life Sciences, Tongji University, Shanghai, P. R. China
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Lejon V, Mumba Ngoyi D, Kestens L, Boel L, Barbé B, Kande Betu V, van Griensven J, Bottieau E, Muyembe Tamfum JJ, Jacobs J, Büscher P. Gambiense human african trypanosomiasis and immunological memory: effect on phenotypic lymphocyte profiles and humoral immunity. PLoS Pathog 2014; 10:e1003947. [PMID: 24603894 PMCID: PMC3946376 DOI: 10.1371/journal.ppat.1003947] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 01/09/2014] [Indexed: 12/25/2022] Open
Abstract
In mice, experimental infection with Trypanosoma brucei causes decreased bone marrow B-cell development, abolished splenic B-cell maturation and loss of antibody mediated protection including vaccine induced memory responses. Nothing is known about this phenomenon in human African trypanosomiasis (HAT), but if occurring, it would imply the need of revaccination of HAT patients after therapy and abolish hope for a HAT vaccine. The effect of gambiense HAT on peripheral blood memory T- and B-cells and on innate and vaccine induced antibody levels was examined. The percentage of memory B- and T-cells was quantified in peripheral blood, prospectively collected in DR Congo from 117 Trypanosoma brucei gambiense infected HAT patients before and six months after treatment and 117 controls at the same time points. Antibodies against carbohydrate antigens on red blood cells and against measles were quantified. Before treatment, significantly higher percentages of memory B-cells, mainly T-independent memory B-cells, were observed in HAT patients compared to controls (CD20+CD27+IgM+, 13.0% versus 2.0%, p<0.001). The percentage of memory T-cells, mainly early effector/memory T-cells, was higher in HAT (CD3+CD45RO+CD27+, 19.4% versus 16.7%, p = 0.003). After treatment, the percentage of memory T-cells normalized, the percentage of memory B-cells did not. The median anti-red blood cell carbohydrate IgM level was one titer lower in HAT patients than in controls (p<0.004), and partially normalized after treatment. Anti-measles antibody concentrations were lower in HAT patients than in controls (medians of 1500 versus 2250 mIU/ml, p = 0.02), and remained so after treatment, but were above the cut-off level assumed to provide protection in 94.8% of HAT patients, before and after treatment (versus 98.3% of controls, p = 0.3). Although functionality of the B-cells was not verified, the results suggest that immunity was conserved in T.b. gambiense infected HAT patients and that B-cell dysfunction might not be that severe as in mouse models.
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Affiliation(s)
- Veerle Lejon
- Institute of Tropical Medicine, Antwerp, Belgium
- Institut de Recherche pour le Développement, UMR 177 IRD-CIRAD INTERTRYP, Montpellier, France
| | - Dieudonné Mumba Ngoyi
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Luc Kestens
- Institute of Tropical Medicine, Antwerp, Belgium
| | - Luc Boel
- Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Victor Kande Betu
- Programme Nationale de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of the Congo
| | | | | | | | - Jan Jacobs
- Institute of Tropical Medicine, Antwerp, Belgium
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12
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Leong S, Simo G, Camara M, Jamonneau V, Kabore J, Ilboudo H, Bucheton B, Hoheisel JD, Clayton C. The miRNA and mRNA Signatures of Peripheral Blood Cells in Humans Infected with Trypanosoma brucei gambiense. PLoS One 2013; 8:e67312. [PMID: 23826264 PMCID: PMC3695006 DOI: 10.1371/journal.pone.0067312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 05/15/2013] [Indexed: 01/08/2023] Open
Abstract
Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II) and without (stage I) brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II), 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested) showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology.
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Affiliation(s)
- Smiths Leong
- Division of Functional Genome Analysis, Deutsche Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Gustave Simo
- Department of Biochemistry, University of Dschang, Dschang, West Cameroon
| | - Mamadou Camara
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine en Guinée, Conakry, Guinée
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Vincent Jamonneau
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
- Institut de Recherche pour le Développement, Unité mixte de recherche 177 (UMR-177), Campus International de Baillarguet, Montpellier, France
| | - Jacques Kabore
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Hamidou Ilboudo
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Bruno Bucheton
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
- Institut de Recherche pour le Développement, Unité mixte de recherche 177 (UMR-177), Campus International de Baillarguet, Montpellier, France
| | - Jörg D. Hoheisel
- Division of Functional Genome Analysis, Deutsche Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
- * E-mail:
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Gillet P, Mumba Ngoyi D, Lukuka A, Kande V, Atua B, van Griensven J, Muyembe JJ, Jacobs J, Lejon V. False positivity of non-targeted infections in malaria rapid diagnostic tests: the case of human african trypanosomiasis. PLoS Negl Trop Dis 2013; 7:e2180. [PMID: 23638201 PMCID: PMC3636101 DOI: 10.1371/journal.pntd.0002180] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 03/14/2013] [Indexed: 11/29/2022] Open
Abstract
Background In endemic settings, diagnosis of malaria increasingly relies on the use of rapid diagnostic tests (RDTs). False positivity of such RDTs is poorly documented, although it is especially relevant in those infections that resemble malaria, such as human African trypanosomiasis (HAT). We therefore examined specificity of malaria RDT products among patients infected with Trypanosoma brucei gambiense. Methodology/Principal Findings Blood samples of 117 HAT patients and 117 matched non-HAT controls were prospectively collected in the Democratic Republic of the Congo. Reference malaria diagnosis was based on real-time PCR. Ten commonly used malaria RDT products were assessed including three two-band and seven three-band products, targeting HRP-2, Pf-pLDH and/or pan-pLDH antigens. Rheumatoid factor was determined in PCR negative subjects. Specificity of the 10 malaria RDT products varied between 79.5 and 100% in HAT-negative controls and between 11.3 and 98.8% in HAT patients. For seven RDT products, specificity was significantly lower in HAT patients compared to controls. False positive reactions in HAT were mainly observed for pan-pLDH test lines (specificities between 13.8 and 97.5%), but also occurred frequently for the HRP-2 test line (specificities between 67.9 and 98.8%). The Pf-pLDH test line was not affected by false-positive lines in HAT patients (specificities between 97.5 and 100%). False positivity was not associated to rheumatoid factor, detected in 7.6% of controls and 1.2% of HAT patients. Conclusions/Significance Specificity of some malaria RDT products in HAT was surprisingly low, and constitutes a risk for misdiagnosis of a fatal but treatable infection. Our results show the importance to assess RDT specificity in non-targeted infections when evaluating diagnostic tests. Rapid diagnostic tests (RDT) for malaria are currently rolled-out as the backbone of parasite-based diagnosis, and their diagnostic accuracy is sufficiently high to substitute microscopy. One decade ago, attention has been given to occurrence of limited false positivity in a number of malaria RDTs, but false positivity of RDTs has remained poorly documented since then. In the last years, the number of available RDT products has dramatically increased and test performance has improved. False positivity may therefore not be perceived as a problem anymore. In this manuscript, we demonstrate that specificities of malaria rapid diagnostic tests detecting parasite antigens are seriously affected by human African trypanosomiasis (sleeping sickness), with values down to 11%. Malaria constitutes the main differential diagnosis of human African trypanosomiasis, and the false-positive results for malaria RDTs increase the risk of misdiagnosis or delayed diagnosis of human African trypanosomiasis which is a fatal but treatable infection.
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Affiliation(s)
- Philippe Gillet
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Dieudonné Mumba Ngoyi
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Albert Lukuka
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Viktor Kande
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Benjamin Atua
- Programme National de Lutte contre le Paludisme (PNLP), Kinshasa, Democratic Republic of the Congo
| | - Johan van Griensven
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Jean-Jacques Muyembe
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Veerle Lejon
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Institut de Recherche pour le Développement, UMR 177 IRD-CIRAD INTERTRYP, Campus International de Baillarguet, Montpellier, France
- * E-mail:
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de Carvalho CA, Partata AK, Hiramoto RM, Borborema SET, Meireles LR, Nascimento ND, de Andrade HF. A simple immune complex dissociation ELISA for leishmaniasis: standardization of the assay in experimental models and preliminary results in canine and human samples. Acta Trop 2013; 125:128-36. [PMID: 23123344 DOI: 10.1016/j.actatropica.2012.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 10/16/2012] [Accepted: 10/20/2012] [Indexed: 12/14/2022]
Abstract
Visceral leishmaniasis, caused by Leishmania (Leishmania) chagasi, is a chronic parasitic disease of humans and dogs. Confirmation of the protozoal agent in bone marrow, lymph node or spleen aspirate is diagnostic, while specific-IgG serology is used mainly for epidemiology despite the general presence of high levels of serum immunoglobulin. Anecdotal reports of false-negative serology in active disease cases are known and are ascribed to the formation of immune complexes. Because dissociation of immune complexes can be accomplished by acid treatment, we devised a simple, routine enzyme immunoassay (ELISA) for the dissociation of immune complexes in serum samples using acid treatment in wells adsorbed with Leishmania antigen (dELISA). Confirmatory acid dot-blot was also developed for antigen detection by anti-Leishmania rabbit antiserum. In experimental L. chagasi hamster models, immune complexes interfered with ELISA mostly in the 30 and 60 days postinfection, according to both dELISA and antigen dot-blot results. In larger samples from endemic areas, dELISA was positive in 10% of seronegative dog samples (7/70) and 3.5% in negative human samples (3/88), showing that dELISA could be used in the serodiagnosis of visceral leishmaniasis. Moreover, dELISA could be used as an alternative approach to screening asymptomatic visceral leishmaniasis patients, instead of invasive confirmatory testing.
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Affiliation(s)
- Camila Aparecida de Carvalho
- Protozoology Laboratory, Instituto de Medicina Tropical de São Paulo, University of São Paulo, São Paulo, SP, Brazil
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15
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Translation of human African trypanosomiasis biomarkers towards field application. TRANSLATIONAL PROTEOMICS 2013. [DOI: 10.1016/j.trprot.2013.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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16
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Van Nieuwenhove L, Büscher P, Balharbi F, Humbert M, Dieltjens T, Guisez Y, Lejon V. Identification of mimotopes with diagnostic potential for Trypanosoma brucei gambiense variant surface glycoproteins using human antibody fractions. PLoS Negl Trop Dis 2012; 6:e1682. [PMID: 22720103 PMCID: PMC3373652 DOI: 10.1371/journal.pntd.0001682] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 04/27/2012] [Indexed: 11/18/2022] Open
Abstract
Background At present, screening of the population at risk for gambiense human African trypanosomiasis (HAT) is based on detection of antibodies against native variant surface glycoproteins (VSGs) of Trypanosoma brucei (T.b.) gambiense. Drawbacks of these native VSGs include culture of infective T.b. gambiense trypanosomes in laboratory rodents, necessary for production, and the exposure of non-specific epitopes that may cause cross-reactions. We therefore aimed at identifying peptides that mimic epitopes, hence called “mimotopes,” specific to T.b. gambiense VSGs and that may replace the native proteins in antibody detection tests. Methodology/Principal Findings A Ph.D.-12 peptide phage display library was screened with polyclonal antibodies from patient sera, previously affinity purified on VSG LiTat 1.3 or LiTat 1.5. The peptide sequences were derived from the DNA sequence of the selected phages and synthesised as biotinylated peptides. Respectively, eighteen and twenty different mimotopes were identified for VSG LiTat 1.3 and LiTat 1.5, of which six and five were retained for assessment of their diagnostic performance. Based on alignment of the peptide sequences on the original protein sequence of VSG LiTat 1.3 and 1.5, three additional peptides were synthesised. We evaluated the diagnostic performance of the synthetic peptides in indirect ELISA with 102 sera from HAT patients and 102 endemic negative controls. All mimotopes had areas under the curve (AUCs) of ≥0.85, indicating their diagnostic potential. One peptide corresponding to the VSG LiTat 1.3 protein sequence also had an AUC of ≥0.85, while the peptide based on the sequence of VSG LiTat 1.5 had an AUC of only 0.79. Conclusions/Significance We delivered the proof of principle that mimotopes for T.b. gambiense VSGs, with diagnostic potential, can be selected by phage display using polyclonal human antibodies. Control of the chronic form of sleeping sickness or gambiense human African trypanosomiasis (HAT) consists of accurate diagnosis followed by treatment. We aim to replace the native variant surface glycoprotein (VSG) parasite antigens that are presently used in most antibody detection tests with peptides that can be synthesised in vitro. Antibodies recognising VSG were purified from HAT patient sera and were used to select phage-expressed peptides that mimic VSG epitopes from a Ph.D.-12 phage display library. The diagnostic potential of the corresponding synthetic peptides was demonstrated in indirect ELISA with sera from HAT patients and endemic negative controls. We proved that diagnostic mimotopes for T.b. gambiense VSGs can be selected by phage display technology, using polyclonal human antibodies.
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Affiliation(s)
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- * E-mail:
| | - Fatima Balharbi
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Michael Humbert
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Tessa Dieltjens
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Yves Guisez
- Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Veerle Lejon
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
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Abstract
At the turn of the 19th century, trypanosomes were identified as the causative agent of sleeping sickness and their presence within the cerebrospinal fluid of late stage sleeping sickness patients was described. However, no definitive proof of how the parasites reach the brain has been presented so far. Analyzing electron micrographs prepared from rodent brains more than 20 days after infection, we present here conclusive evidence that the parasites first enter the brain via the choroid plexus from where they penetrate the epithelial cell layer to reach the ventricular system. Adversely, no trypanosomes were observed within the parenchyma outside blood vessels. We also show that brain infection depends on the formation of long slender trypanosomes and that the cerebrospinal fluid as well as the stroma of the choroid plexus is a hostile environment for the survival of trypanosomes, which enter the pial space including the Virchow-Robin space via the subarachnoid space to escape degradation. Our data suggest that trypanosomes do not intend to colonize the brain but reside near or within the glia limitans, from where they can re-populate blood vessels and disrupt the sleep wake cycles.
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18
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Van Nieuwenhove LC, Rogé S, Balharbi F, Dieltjens T, Laurent T, Guisez Y, Büscher P, Lejon V. Identification of peptide mimotopes of Trypanosoma brucei gambiense variant surface glycoproteins. PLoS Negl Trop Dis 2011; 5:e1189. [PMID: 21695105 PMCID: PMC3114753 DOI: 10.1371/journal.pntd.0001189] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 04/15/2011] [Indexed: 01/28/2023] Open
Abstract
Background The current antibody detection tests for the diagnosis of gambiense human African trypanosomiasis (HAT) are based on native variant surface glycoproteins (VSGs) of Trypanosoma brucei (T.b.) gambiense. These native VSGs are difficult to produce, and contain non-specific epitopes that may cause cross-reactions. We aimed to identify mimotopic peptides for epitopes of T.b. gambiense VSGs that, when produced synthetically, can replace the native proteins in antibody detection tests. Methodology/Principal Findings PhD.-12 and PhD.-C7C phage display peptide libraries were screened with mouse monoclonal antibodies against the predominant VSGs LiTat 1.3 and LiTat 1.5 of T.b. gambiense. Thirty seven different peptide sequences corresponding to a linear LiTat 1.5 VSG epitope and 17 sequences corresponding to a discontinuous LiTat 1.3 VSG epitope were identified. Seventeen of 22 synthetic peptides inhibited the binding of their homologous monoclonal to VSG LiTat 1.5 or LiTat 1.3. Binding of these monoclonal antibodies to respectively six and three synthetic mimotopic peptides of LiTat 1.5 and LiTat 1.3 was significantly inhibited by HAT sera (p<0.05). Conclusions/Significance We successfully identified peptides that mimic epitopes on the native trypanosomal VSGs LiTat 1.5 and LiTat 1.3. These mimotopes might have potential for the diagnosis of human African trypanosomiasis but require further evaluation and testing with a large panel of HAT positive and negative sera. The control of human African trypanosomiasis or sleeping sickness, a deadly disease in sub-Saharan Africa, mainly depends on a correct diagnosis and treatment. The aim of our study was to identify mimotopic peptides (mimotopes) that may replace the native proteins in antibody detection tests for sleeping sickness and hereby improve the diagnostic sensitivity and specificity. We selected peptide expressing phages from the PhD.-12 and PhD.-C7C phage display libraries with mouse monoclonal antibodies specific to variant surface glycoprotein (VSG) LiTat 1.3 or LiTat 1.5 of Trypanosoma brucei gambiense. The peptide coding genes of the selected phages were sequenced and the corresponding peptides were synthesised. Several of the synthetic peptides were confirmed as mimotopes for VSG LiTat 1.3 or LiTat 1.5 since they were able to inhibit the binding of their homologous monoclonal to the corresponding VSG. These peptides were biotinylated and their diagnostic potential was assessed with human sera. We successfully demonstrated that human sleeping sickness sera recognise some of the mimotopes of VSG LiTat 1.3 and LiTat 1.5, indicating the diagnostic potential of such peptides.
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19
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Padilla-Docal B, Dorta-Contreras AJ, Moreira JM, Martini-Robles L, Muzzio-Aroca J, Alarcón F, Magraner-Tarrau ME, Bu-Coifiu-Fanego R. Comparison of major immunoglobulins intrathecal synthesis patterns in Ecuadorian and Cuban patients with angiostrongyliasis. Am J Trop Med Hyg 2011; 84:406-10. [PMID: 21363978 DOI: 10.4269/ajtmh.2011.10-0500] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Angiostrongylus cantonensis meningitis was first reported in Cuba in 1981, and it was recently reported in South America. The aim of this paper is to evaluate the intrathecal immunoglobulin synthesis patterns from Cuba's and Ecuador's patients with angiostrongyliasis; 8 Ecuadorian patients from two different outbreaks and 28 Cuban patients were studied. Simultaneous blood and cerebrospinal fluid samples were taken. Immunoglobulin (Ig) A, IgM, IgG, and albumin were quantified by radial immunodiffusion. Corresponding Reibergrams were applied. A three-Ig pattern was the most frequent in the two groups, but IgM was presented in all Ecuadorian young mature patients; however, in the Cuban children, only 12 of 28 patients had intrathecal IgM, but about 90% had an IgA and IgG synthesis at time of later puncture. This indicates that, with a larger amount of parasites ingested, clinical symptoms are more severe, and a higher frequency of intrathecal IgM synthesis could be observed. This is discussed as a similarity with the intrathecal IgM synthesis in African trypanosomiasis.
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Affiliation(s)
- Bárbara Padilla-Docal
- Laboratorio Central de Líquido Cefalorraquídeo (LABCEL), Facultad de Ciencias Médicas Dr. Miguel Enríquez, Universidad de Ciencias Médicas de La Habana, Havana, Cuba.
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20
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Low specificities of HIV diagnostic tests caused by Trypanosoma brucei gambiense sleeping sickness. J Clin Microbiol 2010; 48:2836-9. [PMID: 20573878 DOI: 10.1128/jcm.00456-10] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The accuracy of diagnostic tests for HIV in patients with tropical infections is poorly documented. Human African trypanosomiasis (HAT) is characterized by a polyclonal B-cell activation, constituting a risk for false-positive reactions to diagnostic tests, including HIV tests. A retrospective study of the accuracy of HIV diagnostic tests was performed with 360 human African HAT patients infected with Trypanosoma brucei gambiense before treatment and 163 T. b. gambiense-infected patients 2 years after successful treatment in Mbuji Mayi, East Kasai, Democratic Republic of the Congo. The sensitivities, specificities, and positive predictive values (PPVs) of individual tests and algorithms consisting of 3 rapid tests were determined. The sensitivity of all tests was 100% (11/11). The low specificity (96.3%, 335/348) and PPV (45.8%, 11/24) of a classical seroconfirmation strategy (Vironostika enzyme-linked immunosorbent assay [ELISA] followed by line immunoassay) complicated the determination of HIV status, which had to be determined by PCR. The specificities of the rapid diagnostic tests were 39.1% for Determine (136/348); 85.3 to 92.8% (297/348 to 323/348) for Vikia, ImmunoFlow, DoubleCheck, and Bioline; and 96.6 to 98.3% (336/348 to 342/348) for Uni-Gold, OraQuick, and Stat-Pak. The specificity of Vironostika was 67.5% (235/348). PPVs ranged between 4.9 and 64.7%. Combining 3 different rapid tests resulted in specificities of 98.3 to 100% (342/348 to 348/348) and PPVs of 64.7 to 100% (11/17 to 11/11). For cured HAT patients, specificities were significantly higher for Vironostika, Determine, Uni-Gold, and ImmunoFlow. T. b. gambiense infection decreases the specificities of antibody detection tests for HIV diagnosis. Unless tests have been validated for interference with HAT, HIV diagnosis using classical algorithms in untreated HAT patients should be avoided. Specific, validated combinations of 3 HIV rapid tests can increase specificity.
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21
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Immunobiology of African trypanosomes: need of alternative interventions. J Biomed Biotechnol 2010; 2010:389153. [PMID: 20182644 PMCID: PMC2826769 DOI: 10.1155/2010/389153] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 10/29/2009] [Accepted: 12/23/2009] [Indexed: 02/08/2023] Open
Abstract
Trypanosomiasis is one of the major parasitic diseases for which control is still far from reality. The vaccination approaches by using dominant surface proteins have not been successful, mainly due to antigenic variation of the parasite surface coat. On the other hand, the chemotherapeutic drugs in current use for the treatment of this disease are toxic and problems of resistance are increasing (see Kennedy (2004) and Legros et al. (2002)). Therefore, alternative approaches in both treatment and vaccination against trypanosomiasis are needed at this time. To be able to design and develop such alternatives, the biology of this parasite and the host response against the pathogen need to be studied. These two aspects of this disease with few examples of alternative approaches are discussed here.
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22
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Rodgers J. Human African trypanosomiasis, chemotherapy and CNS disease. J Neuroimmunol 2009; 211:16-22. [DOI: 10.1016/j.jneuroim.2009.02.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 02/05/2009] [Indexed: 11/28/2022]
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23
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Rodrigues A, Fighera RA, Souza TM, Schild AL, Barros CSL. Neuropathology of Naturally Occurring Trypanosoma evansi Infection of Horses. Vet Pathol 2009; 46:251-8. [DOI: 10.1354/vp.46-2-251] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The clinical signs and pathology of the central nervous system in 9 horses with naturally occurring neurologic disease due to Trypanosoma evansi are described. The clinical course was 2 to 20 days; clinical signs included marked ataxia, blindness, head tilt and circling, hyperexcitability, obtundity, proprioceptive deficits, head pressing, and paddling movements. Grossly, asymmetric leukoencephalomalacia with yellowish discoloration of white matter and flattening of the gyri were observed in the brain of 7 of 9 horses. Histologically, all 9 horses had necrotizing encephalitis that was most severe in the white matter, with edema, demyelination, and lymphoplasmacytic perivascular cuffs. Mild to moderate meningitis or meningomyelitis was observed in the spinal cord of 5 of 7 horses. T. evansi was detected immunohistochemically in the perivascular spaces and neuropil of formalin-fixed, paraffin-embedded brain tissue in 8 of 9 horses.
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Affiliation(s)
- A. Rodrigues
- Departamento de Patologia, Universidade Federal de Santa Maria, Santa
Maria, Brazil
| | - R. A. Fighera
- Departamento de Patologia, Universidade Federal de Santa Maria, Santa
Maria, Brazil
| | - T. M. Souza
- Departamento de Patologia, Universidade Federal de Santa Maria, Santa
Maria, Brazil
| | - A. L. Schild
- Laboratório Regional de Diagnóstico, Faculdade de Veterinária,
Universidade Federal de Pelotas, Pelotas, Brazil
| | - C. S. L. Barros
- Departamento de Patologia, Universidade Federal de Santa Maria, Santa
Maria, Brazil
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24
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Lemos KR, Marques LC, Aquino LPCT, Alessi AC, Zacarias RZ. Astrocytic and microglial response and histopathological changes in the brain of horses with experimental chronic Trypanosoma evansi infection. Rev Inst Med Trop Sao Paulo 2008; 50:243-9. [DOI: 10.1590/s0036-46652008000400011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Accepted: 06/05/2008] [Indexed: 11/22/2022] Open
Abstract
This study aimed to characterize astrocytic and microglial response in the central nervous system (CNS) of equines experimentally infected with T. evansi. The experimental group comprised males and females with various degrees of crossbreeding, ages between four and seven years. The animals were inoculated intravenously with 10(6) trypomastigotes of T. evansi originally isolated from a naturally infected dog. All equines inoculated with T. evansi were observed until they presented symptoms of CNS disturbance, characterized by motor incoordination of the pelvic limbs, which occurred 67 days after inoculation (DAI) and 124 DAI. The animals in the control group did not present any clinical symptom and were observed up to the 125th DAI. For this purpose the HE histochemical stain and the avidin biotin peroxidase method was used. Lesions in the CNS of experimentally infected horses were those of a wide spread non suppurative meningoencephalomyelitis.The severity of lesions varied in different parts of the nervous system, reflecting an irregular distribution of inflammatory vascular changes. The infiltration of mononuclear cells was associated with anisomorphic gliosis and reactive microglia was identified. The intensity of the astrocytic response in the CNS of the equines infected by T. evansi characterizes the importance of the performance of these cells in this trypanosomiasis. The characteristic gliosis observed in the animals in this experiment suggests the ability of these cells as mediators of immune response. The parasite, T. evansi, was not identified in the nervous tissues.
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25
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Abstract
African (sleeping sickness) and American (Chagas' disease) trypanosomiasis, caused by protozoa of the family Trypanosomatidae, are diseases that are endemic in parts of Africa and Latin America, respectively. Physicians in developed countries may occasionally see cases because of extensive travel and immigration from endemic countries. Although neurological involvement is common in both, its incidence and clinical presentation differ considerably. African trypanosomiasis, caused by subspecies of Trypanosoma brucei (T b rhodesiense, T b gambiense), is transmitted by the tsetse fly and causes meningoencephalitis, in which somnolence is a prominent feature. Parasites may reach the brain parenchyma through the choroid plexus or the Virchow Robin spaces. American trypanosomiasis, caused by Trypanosoma cruzi is transmitted by reduviid bugs. While lesions in the central nervous system are not prominent, except in the reactivated forms which occur in immunodeficient patients, the peripheral nerve, mainly the autonomic nervous system, is frequently involved, leading to the cardiomegaly and the digestive megaviscera. Congenital infections may also occur. In this paper we give an account of the epidemiology, clinical presentation and pathological features of these two protozoal infections based on human and experimental studies of both the central and peripheral nervous system.
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Affiliation(s)
- L Chimelli
- Department of Pathology, School of Medicine of Ribeiräo Preto, SP, Brasil.
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26
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Kennedy PGE. Diagnostic and neuropathogenesis issues in human African trypanosomiasis. Int J Parasitol 2006; 36:505-12. [PMID: 16546191 DOI: 10.1016/j.ijpara.2006.01.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 01/23/2006] [Accepted: 01/30/2006] [Indexed: 11/17/2022]
Abstract
Human African trypanosomiasis, also known as sleeping sickness, is caused by protozoan parasites of the genus Trypanosoma, and is a major cause of human mortality and morbidity. The East African and West African variants, caused by Trypanosma brucei rhodesiense and Trypanosoma brucei gambiense, respectively, differ in their presentation but the disease is fatal if untreated. Accurate staging of the disease into the early haemolymphatic stage and the late encephalitic stage is critical as the treatment for the two stages is different. The only effective drug for late stage disease, melarsoprol, which crosses the blood-brain barrier, is followed by a severe post-treatment reactive encephalopathy in 10% of cases of which half die. There is no current consensus on the diagnostic criteria for CNS involvement and the specific indications for melarsoprol therapy also differ. There is a pressing need for a quick, simple, cheap and reliable diagnostic test to diagnose Human African trypanosomiasis in the field and also to determine CNS invasion. Cerebrospinal fluid and plasma analyses in patients with Human African trypanosomiasis have indicated a role for both pro-inflammatory and counter-inflammatory cytokines in determining the severity of the meningoencephalitis of late stage disease, and, at least in T. b. rhodesiense infection, the balance of these opposing cytokines may be critical. Rodent models of Human African trypanosomiasis have proved very useful in modelling the post-treatment reactive encephalopathy of humans and have demonstrated the central role of astrocyte activation and cytokine balances in determining CNS disease. Such animal models have also allowed a greater understanding of the more direct mechanisms of trypanosome infection on CNS function including the disruption of circadian rhythms, as well as the immunological determinants of passage of trypanosomes across the blood-brain barrier.
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Affiliation(s)
- Peter G E Kennedy
- Division of Clinical Neurosciences, Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, University of Glasgow, Glasgow G51 4TF, Scotland, UK.
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27
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Abstract
Human African trypanosomiasis or sleeping sickness is caused by infection with two subspecies of the tsetse-fly-vectored haemoflagellate parasite Trypanosoma brucei. Historically, epidemic sleeping sickness has caused massive loss of life, and related animal diseases have had a crucial impact on development in sub-Saharan Africa. After a period of moderately successful control during the mid-part of the 20th century, sleeping sickness incidence is currently rising, and control is hampered by a combination of factors, including civil unrest and the possible development of drug resistance by the parasites. The prevailing view is that the disease is invariably fatal without anti-trypanosomal drug treatment. However, there have also been intriguing reports of wide variations in disease severity as well as evidence of asymptomatic carriers of trypanosomes. These differences in the presentation of the disease will be discussed in the context of our knowledge of the immunology of trypanosomiasis. The impact of dysregulated inflammatory responses in both systemic and CNS pathology will be examined and the potential for host genotype variation in disease severity and control will be discussed.
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Affiliation(s)
- J M Sternberg
- Zoology Building, School of Biological Sciences, University of Aberdeen, UK.
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28
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Chappuis F, Loutan L, Simarro P, Lejon V, Büscher P. Options for field diagnosis of human african trypanosomiasis. Clin Microbiol Rev 2005; 18:133-46. [PMID: 15653823 PMCID: PMC544181 DOI: 10.1128/cmr.18.1.133-146.2005] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense or T. b. rhodesiense remains highly prevalent in several rural areas of sub-Saharan Africa and is lethal if left untreated. Therefore, accurate tools are absolutely required for field diagnosis. For T. b. gambiense HAT, highly sensitive tests are available for serological screening but the sensitivity of parasitological confirmatory tests remains insufficient and needs to be improved. Screening for T. b. rhodesiense infection still relies on clinical features in the absence of serological tests available for field use. Ongoing research is opening perspectives for a new generation of field diagnostics. Also essential for both forms of HAT is accurate determination of the disease stage because of the high toxicity of melarsoprol, the drug most widely used during the neurological stage of the illness. Recent studies have confirmed the high accuracy of raised immunoglobulin M levels in the cerebrospinal fluid for the staging of T. b. gambiense HAT, and a promising simple assay (LATEX/IgM) is being tested in the field. Apart from the urgent need for better tools for the field diagnosis of this neglected disease, improved access to diagnosis and treatment for the population at risk remains the greatest challenge for the coming years.
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Affiliation(s)
- François Chappuis
- Travel and Migration Medicine Unit, Geneva University Hospital, 24 rue Micheli-du-Crest, 1211 Geneva 14, Switzerland.
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Kennedy PG. Human African trypanosomiasis of the CNS: current issues and challenges. J Clin Invest 2004. [DOI: 10.1172/jci200421052] [Citation(s) in RCA: 205] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Kennedy PGE. Human African trypanosomiasis of the CNS: current issues and challenges. J Clin Invest 2004; 113:496-504. [PMID: 14966556 PMCID: PMC338269 DOI: 10.1172/jci21052] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Human African trypanosomiasis (HAT), also known as sleeping sickness, is a major cause of mortality and morbidity in sub-Saharan Africa. Current therapy with melarsoprol for CNS HAT has unacceptable side-effects with an overall mortality of 5%. This review discusses the issues of diagnosis and staging of CNS disease, its neuropathogenesis, and the possibility of new therapies for treating late-stage disease.
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Affiliation(s)
- Peter G E Kennedy
- Department of Neurology, Division of Clinical Neurosciences, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, United Kingdom.
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31
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Lejon V, Sindic CJM, Van Antwerpen MP, Doua F, Djé N, Solano P, Jamonneau V, Wouters I, Büscher P. Human African trypanosomiasis: quantitative and qualitative assessment of intrathecal immune response. Eur J Neurol 2003; 10:711-9. [PMID: 14641518 DOI: 10.1046/j.1468-1331.2003.00660.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Quantitative and qualitative techniques for assessment of the intrathecal humoral immune response in human African trypanosomiasis were compared, and their diagnostic potential for detection of the meningo-encephalitic stage of the disease was evaluated. Total and trypanosome specific immunoglobulin G (IgG) and IgM intrathecal synthesis were studied in paired cerebrospinal fluid (CSF) and blood samples of 38 trypanosomiasis patients and in three controls using Reiber's formulae. The presence of CSF-specific oligoclonal IgG and of trypanosome-specific antibodies was determined using iso-electric focusing followed by immunoblotting and antigen-driven immunoblots. The intrathecal IgG fraction (16% positive) and oligoclonal IgG detection (24% positive) were insensitive for detection of an intrathecal humoral immune response. Trypanosome-specific IgG synthesis, reflected by the IgG antibody index (AI) (26% positive), was confirmed by the presence of oligoclonal specific IgG (47% positive), but the latter was more sensitive. Although the detection technique failed for oligoclonal IgM, the intrathecal IgM fraction (42% positive) and the IgM AI (32% positive) indicated that the meningo-encephalitic stage of the disease is characterized by a dominant intrathecal IgM response, which was higher than the IgG response. The highest combination of diagnostic sensitivity and specificity for the meningo-encephalitic stage of trypanosomiasis was observed for quantitative IgM determinations.
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Affiliation(s)
- V Lejon
- Department of Parasitology, Institute of Tropical Medicine, Antwerpen, Belgium.
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Jennings FW, Rodgers J, Bradley B, Gettinby G, Kennedy PGE, Murray M. Human African trypanosomiasis: potential therapeutic benefits of an alternative suramin and melarsoprol regimen. Parasitol Int 2002; 51:381-8. [PMID: 12421636 DOI: 10.1016/s1383-5769(02)00044-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Treatment of late-stage human African trypanosomiasis is complicated by the presence of trypanosomes within the central nervous system (CNS). The regimen commonly prescribed to treat CNS-stage disease involves the use of the trypanocidal drugs suramin and melarsoprol. Suramin does not cross the blood-brain barrier efficiently and therefore, at normal dosages, will not cure CNS-stage infections. An initial treatment with suramin is given to eliminate the parasites from the peripheral tissues. This is followed by a course of intravenous melarsoprol, which can enter the CNS. However, melarsoprol not only produces severe adverse reactions but also is extremely painful to administer. One possible method to help alleviate these problems is to reduce the total amount of melarsoprol in the treatment regimen. This study indicates a synergism between suramin and melarsoprol and demonstrates that experimental murine CNS-trypanosomiasis can be cured with a single intraperitoneal dose of 20 mg/kg suramin followed almost immediately by 0.05 ml (4.5 micromol) topical melarsoprol. These dosages will not cure the infection when administered as monotherapies. Moreover, the timing of the drug administration appears to be crucial to the successful outcome of the regimen. If the interval between injection of suramin and application of topical melarsoprol is extended from 15 min to 3 or 7 days, the infections are not cured. Although extended relapse times occur following these regimens when compared with monotherapy approaches. Thus, there is strong evidence that injected suramin and topical melarsoprol should be given almost simultaneously to achieve the most effective combination of the two drugs.
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Affiliation(s)
- Frank W Jennings
- Department of Veterinary Clinical Studies, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, Scotland, UK
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33
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Bisser S, Lejon V, Preux PM, Bouteille B, Stanghellini A, Jauberteau MO, Büscher P, Dumas M. Blood-cerebrospinal fluid barrier and intrathecal immunoglobulins compared to field diagnosis of central nervous system involvement in sleeping sickness. J Neurol Sci 2002; 193:127-35. [PMID: 11790393 DOI: 10.1016/s0022-510x(01)00655-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Diagnosis of central nervous system (CNS) involvement in sleeping sickness is crucial in order to give an appropriate treatment regimen. Neurological symptoms occur late, therefore field diagnosis is based on white blood cell count, total protein concentration and presence of trypanosomes in cerebrospinal fluid (CSF). More sensitive and specific parameters are now available. Blood-CSF barrier (B-CSFB) dysfunction, intrathecal total and specific immunoglobulin synthesis were evaluated in 95 patients with and without obvious meningoencephalitis, and compared to field criteria.B-CSFB dysfunction is a rather late event in the course of CNS involvement and correlates with the presence of trypanosomes, neurological signs and intrathecal polyspecific and specific immune response. IgM intrathecal response and particularly IgM antibody index are early markers of CNS invasion. We showed that 29% of patients with CSF abnormalities but without trypanosome detection in the field had no neuro-immunological response. In contrast, patients with normal CSF according to field diagnosis showed an intrathecal immune response in 31% of the cases.Field diagnosis can therefore fail to determine neurological involvement but can also provide false positive results. Improved criteria including B-CSFB dysfunction and IgM detection are needed in order to provide an adapted treatment regimen.
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Affiliation(s)
- S Bisser
- Institut d'Epidémiologie Neurologique et de Neurologie Tropicale (EA3174), Faculté de Médecine, 2 rue du Docteur Raymond Marcland, 87025 Limoges Cédex, France.
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34
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Kennedy PG. The pathogenesis and modulation of the post-treatment reactive encephalopathy in a mouse model of Human African Trypanosomiasis. J Neuroimmunol 1999; 100:36-41. [PMID: 10695713 DOI: 10.1016/s0165-5728(99)00196-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Drug treatment of late-stage human African Trypanosomiasis (HAT) in which the central nervous system (CNS) is involved may be complicated by a severe post-treatment reactive encephalopathy (PTRE) which can be fatal in up to 10% of cases. In order to understand the immunopathogenesis of this complication, an experimental mouse model has been developed that mirrors many of the pathological features of the PTRE in humans, and which allows various anti-inflammatory therapeutic regimes to be evaluated. Following the development of the PTRE in this model a number of cytokines are increased within the CNS including tumour necrosis factor (TNF) alpha, interleukins 1, 4 and 6, and macrophage inflammatory protein (MIP)-1. These cytokines appear at the same time as astrocyte activation which is an early event occurring before the development of the marked meningoencephalitic inflammatory response. The immunosuppressant drug azathioprine prevents but does not reduce the severity of an established PTRE and has a minimal effect on astrocyte activation. The ornithine decarboxylase inhibitor eflornithine prevents the induction, and ameliorates the severity, of the PTRE, and also reduces the degree of astrocyte activation. The Substance P antagonist RP-67,580 ameliorates the severity of an established PTRE, and also reduces astrocyte activation, indicating an important role of SP in the generation of the inflammatory response. Continued use of this mouse model should lead to further enhancement of our understanding of the pathogenesis of the PTRE and to improved drug regimes to prevent and/or treat it.
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Affiliation(s)
- P G Kennedy
- Glasgow University Department of Neurology, Southern General Hospital, South Glasgow University Hospitals NHS Trust, Scotland, UK.
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Lejon V, Büscher P, Magnus E, Moons A, Wouters I, Van Meirvenne N. A semi-quantitative ELISA for detection of Trypanosoma brucei gambiense specific antibodies in serum and cerebrospinal fluid of sleeping sickness patients. Acta Trop 1998; 69:151-64. [PMID: 9588235 DOI: 10.1016/s0001-706x(97)00137-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A semi-quantitative ELISA, using variable surface glycoprotein of T.b. gambiense as antigen, was developed for the detection of antibodies of different immunoglobulin isotypes in serum and cerebrospinal fluid of sleeping sickness patients. Using the assay, the antibody profiles of paired serum and cerebrospinal fluid samples of 28 patients have been studied. Total concentrations of various Ig isotypes were determined as well. In serum and cerebrospinal fluid a drastic increase in IgG, basically IgG1, as well as in IgM levels was observed. The concentration of IgA remained relatively normal. The antitrypanosomal antibodies detected in serum and cerebrospinal fluid were mainly of the IgG (IgG1 and IgG3) and IgM isotypes. Measurement of immunoglobulin and trypanosome specific antibody concentrations in serum and CSF allows calculation of intrathecal antibody synthesis and is a possible tool for determining the clinical stage of sleeping sickness.
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Affiliation(s)
- V Lejon
- Institute of Tropical Medicine, Department of Parasitology, Antwerpen, Belgium.
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36
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Lejon V, Büscher P, Sema NH, Magnus E, Van Meirvenne N. Human African trypanosomiasis: a latex agglutination field test for quantifying IgM in cerebrospinal fluid. Bull World Health Organ 1998; 76:553-8. [PMID: 10191550 PMCID: PMC2312495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
LATEX/IgM, a rapid agglutination test for the semi-quantitative detection of IgM in cerebrospinal fluid of patients with African trypanosomiasis, is described in this article. The lyophilized reagent has been designed for field use and remains stable at 45 degrees C for one year. The test has been evaluated on cerebrospinal fluid samples from trypanosome-infected and non-infected patients, by comparison with commercial latex agglutination, radial immunodiffusion, and nephelometry. All test systems yielded similar results.
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Affiliation(s)
- V Lejon
- Department of Parasitology, University of Antwerp, Belgium
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37
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Kennedy PG, Rodgers J, Jennings FW, Murray M, Leeman SE, Burke JM. A substance P antagonist, RP-67,580, ameliorates a mouse meningoencephalitic response to Trypanosoma brucei brucei. Proc Natl Acad Sci U S A 1997; 94:4167-70. [PMID: 9108123 PMCID: PMC20588 DOI: 10.1073/pnas.94.8.4167] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/1997] [Indexed: 02/04/2023] Open
Abstract
Mice infected with the protozoan parasite Trypanosoma brucei brucei and treated subcuratively with the trypanocidal drug diminazene aceturate develop an acute inflammatory meningoencephalitis with associated astrocytic proliferation. This reaction is very similar to that seen in the fatal posttreatment reactive encephalopathies that can occur in human African trypanosomiasis. The 11-amino acid neuropeptide substance P (SP) has recently been identified as a mediator in many inflammatory responses, and the development of potent, highly specific, nonpeptide SP antagonists has provided a new opportunity to investigate the possible involvement of SP in a variety of pathological conditions. We therefore postulated that SP may play a role in the development of the posttreatment inflammatory encephalopathy found in this experimental mouse model of African trypanosomiasis. In the present study RP-67,580, a SP antagonist that binds specifically to NK-1 receptors, was given intraperitoneally at a dose of 2 mg/kg twice daily to mice in which a severe meningoencephalitis had been produced. A significant reduction in both the severity of the inflammatory response (P = 0.0001) as well as the degree of astrocyte activation (P < 0.001) was found in the brains of these animals as compared with control mice that had not received RP-67,580. An inactive enantiomer of this SP antagonist, RP-68,651, had no effect on the central nervous system inflammatory reaction. We conclude from these findings that the neuropeptide SP plays a key role in the development of the severe central nervous system inflammatory response associated with African trypanosomiasis.
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Affiliation(s)
- P G Kennedy
- Department of Neurology, University of Glasgow, United Kingdom
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38
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Pentreath VW, Alafiatayo RA, Crawley B, Doua F, Oppenheim BA. Endotoxins in the blood and cerebrospinal fluid of patients with African sleeping sickness. Parasitology 1996; 112 ( Pt 1):67-73. [PMID: 8587803 DOI: 10.1017/s0031182000065082] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endotoxin levels were measured in the blood and cerebrospinal fluid (CSF) of control individuals and 2 groups of patients with African sleeping sickness. Endotoxin levels were markedly elevated in the blood (infected groups mean endotoxin values 40.2 pg/ml and 53.8 pg/ml, compared to control 11.6 pg/ml, P < 0.0001 for both increases) and CSF (infected groups mean endotoxin values 45.8 pg/ml and 50.1 pg/ml compared to control 6.3 pg/ml, P < 0.0001 for both increases) of the patients. The levels were reduced 6 weeks following different drug treatments in the 2 groups (blood levels to mean 33.8 pg/ml and 28.5 pg/ml; CSF levels to 37.4 pg/ml and 27.0 pg/ml). The blood endotoxin values correlated with the CSF values before treatment (r = 0.74 and 0.57 for the 2 groups; P < 0.0001 for both) and after treatment (r = 0.57 and 0.56 for the 2 groups; P < 0.0001 for both). It is concluded that raised endotoxin equilibrates in the blood and CSF compartments, and may contribute significantly to the pathology of sleeping sickness.
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Affiliation(s)
- V W Pentreath
- Department of Biological Sciences, University of Salford
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39
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Pentreath VW. Royal Society of Tropical Medicine and Hygiene Meeting at Manson House, London, 19 May 1994. Trypanosomiasis and the nervous system. Pathology and immunology. Trans R Soc Trop Med Hyg 1995; 89:9-15. [PMID: 7747319 DOI: 10.1016/0035-9203(95)90637-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Damage to the nervous system occurs in both African and American trypanosomiases, but it differs considerably in form and extent in each disease, and with different strains and disease stages. With Trypanosoma brucei infections there is a progressive central nervous system (CNS) pathology which involves the meninges, choroid, blood-brain barrier, and immunopathological changes including perivascular infiltrations, astrocyte activation and alterations in the cytokine/mediator network. These changes underly the altered behaviour in the late or secondary disease stages, prevalent in the chronic gambian form, characterized by hypersomnia leading, if untreated or if treatment is followed by reactive changes, to coma and death. T. cruzi infections can be divided into 3 stages; acute, intermediate and chronic. Each stage has a different neurological involvement. In the acute stage the parasite produces direct destructive and inflammatory changes in the CNS which can be life-threatening, but which normally resolve, giving way to an intermediate period with effective parasite suppression and little or no perpetuation in the nervous system. The chronic stage is characterized by alteration to a progressive peripheral neuroimmunopathology, with autoimmune destruction of many nerve components, especially the autonomic innervation of the heart and gut.
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Affiliation(s)
- V W Pentreath
- Department of Biological Sciences, University of Salford, UK
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40
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Philip KA, Dascombe MJ, Fraser PA, Pentreath VW. Blood-brain barrier damage in experimental African trypanosomiasis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1994; 88:607-16. [PMID: 7893174 DOI: 10.1080/00034983.1994.11812911] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
African sleeping sickness is characterized by progressive central nervous system (CNS) involvement, leading to the so-called secondary or late stage in which there are widespread inflammatory changes with lymphoplasmocytic infiltration. A study was made of blood-brain barrier (BBB) integrity in the late stages of a rodent model by assessing the uptake of the fluorescent fluid-phase marker sulphorhodamine B into the brain tissue. Brain oedema was estimated from brain weight, density and electrolyte concentrations. Trypanosome distribution was studied by light and electron microscopy. At 35 days post-infection (p.i.) fluorescent dye penetration occurred in several brain regions, including thalamus and hypothalamus. At 40 days p.i., BBB damage was extensive, with dye penetration throughout both the grey and the white matter of the cortex. Infected rats had significantly higher brain water content than uninfected controls and altered sodium and potassium concentrations characteristic of vasogenic oedema. The morphological studies showed early accumulation of parasites within, and associated damage to the choroid plexus, and, in the late stages, the presence of small numbers of trypansomes scattered in the nerve tissue of the brain and spinal cord, similar to previous descriptions. The findings show that chronic trypanosomiasis in the rat model is accompanied by BBB damage and vasogenic oedema.
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Affiliation(s)
- K A Philip
- Department of Biological Sciences, University of Salford, U.K
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41
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Authié E, Duvallet G, Robertson C, Williams DJ. Antibody responses to a 33 kDa cysteine protease of Trypanosoma congolense: relationship to 'trypanotolerance' in cattle. Parasite Immunol 1993; 15:465-74. [PMID: 8233561 DOI: 10.1111/j.1365-3024.1993.tb00632.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A cysteine protease of Trypanosoma congolense (congopain) elicited IgG1 antibodies in those cattle which exhibited a degree of resistance to disease during experimental infections (Authié et al. 1992, 1993). The aim of the present study was to investigate further the association between anti-congopain antibodies and resistance to trypanosomiasis, and to provide a lead into the mechanisms responsible for the differential responses to congopain in cattle. Isotype characteristics and kinetics of the antibody response to congopain were studied in three N'Dama (trypanoresistant) and three Boran (susceptible) cattle during primary infection with T. congolense ILNat 3.1. In both groups an IgM response to congopain was elicited, thus demonstrating that congopain is antigenic in both types of cattle. Most of the IgM appeared to be incorporated into immune complexes. IgG was detected as free antibody; IgG1 but not IgG2 was detected. All three N'Dama, but none of the three Boran cattle, mounted a significant IgG response to congopain. Sera from 70 primary-infected cattle belonging to five breeds of differing susceptibility were tested for their reactivity to congopain. High levels of IgG to congopain were observed in the two trypanotolerant breeds, whereas the three susceptible breeds had lower levels of these antibodies. Crosses between N'Dama and Boran cattle, which exhibit an intermediate susceptibility, had intermediate levels of antibodies. Thus, the results from experimental infections confirmed our initial observations. However, under natural tsetse challenge, repeated infections and trypanocidal treatments in Zebu cattle stimulated as high anti-congopain antibody levels as in non-treated trypanotolerant taurine cattle.
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Affiliation(s)
- E Authié
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
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42
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Hunter CA, Jennings FW, Tierney JF, Murray M, Kennedy PG. Correlation of autoantibody titres with central nervous system pathology in experimental African trypanosomiasis. J Neuroimmunol 1992; 41:143-8. [PMID: 1281824 DOI: 10.1016/0165-5728(92)90064-r] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
CD-1 mice infected with the protozoan parasite Trypanosoma brucei brucei developed few signs of central nervous system pathology associated with the invasion of the central nervous system by these parasites and did not survive beyond 5-6 weeks with deaths common before this time point. However, use of the trypanocidal drug diminazene aceturate (40 mg/kg), which fails to cross the blood-brain barrier, on day 21 post-infection led to the development of central nervous system pathology similar to that seen in the fatal post-treatment reactive encephalopathies that can occur in human African trypanosomiasis. Enzyme-linked immunosorbent assays were used to measure autoantibody titres to double-stranded DNA, myelin basic protein and to the myelin-specific galactocerebrosides and gangliosides in groups of infected mice, with or without the post-treatment reaction, on day 30 post-infection and compared with uninfected controls. Infection with T. brucei brucei raised the titres of all of these autoantibodies. Treatment of infected mice with diminazene aceturate resulted in elevated levels of all of these autoantibodies compared to the untreated animals. There was a strong positive correlation between the central nervous system pathology and the levels of autoantibodies to myelin basic protein, galactocerebrosides and gangliosides, but not to double-stranded DNA. The elevated titres observed may be a consequence of the polyclonal B cell activation that is believed to occur in African trypanosomiasis, parasite epitopes that are cross-reactive with these central nervous system (CNS)-specific antigens or result from the CNS damage associated with sub-curative chemotherapy.
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Affiliation(s)
- C A Hunter
- Department of Veterinary Medicine, University of Glasgow, UK
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Hunter CA, Jennings FW, Adams JH, Murray M, Kennedy PG. Subcurative chemotherapy and fatal post-treatment reactive encephalopathies in African trypanosomiasis. Lancet 1992; 339:956-8. [PMID: 1348799 DOI: 10.1016/0140-6736(92)91531-c] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The treatment of late-stage African sleeping sickness in man is often complicated by a post-treatment reactive encephalopathy. The bases of this pathological reaction was investigated in a mouse model of African trypanosomiasis. Subcurative treatment with diminazene aceturate, which did not clear parasites from the central nervous system, resulted in a post-treatment meningoencephalitis similar to that seen in man. By contrast, a curative regimen of melaminylthioarsenite and 5-nitroimidazole, which cleared parasites from the central nervous system, did not cause any pathological reaction in the mice. This result indicates that subcurative treatment leads to the development of the post-treatment encephalopathy. Evidence that this may also be the case in man was provided by the detection of trypanosome DNA with the polymerase chain reaction in the brains of 9 patients who had died as the result of a post-treatment reaction. Our findings suggest that more aggressive treatment regimens, which ensure the elimination of trypanosomes from the central nervous system, may prevent post-treatment reactions in patients.
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Affiliation(s)
- C A Hunter
- Department of Veterinary Medicine, University of Glasgow, UK
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44
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Hunter CA, Kennedy PG. Immunopathology in central nervous system human African trypanosomiasis. J Neuroimmunol 1992; 36:91-5. [PMID: 1531053 DOI: 10.1016/0165-5728(92)90040-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- C A Hunter
- Glasgow University Department of Neurology, Southern General Hospital, Scotland, UK
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45
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Pepin J, Milord F. African trypanosomiasis and drug-induced encephalopathy: risk factors and pathogenesis. Trans R Soc Trop Med Hyg 1991; 85:222-4. [PMID: 1887477 DOI: 10.1016/0035-9203(91)90032-t] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Data on 598 patients with Trypanosoma brucei gambiense sleeping sickness, with abnormal cerebrospinal fluid (CSF) and treated with melarsoprol, were reviewed to determine risk factors for drug-induced encephalopathy. The incidence of melarsoprol-induced encephalopathy was increased in patients with trypanosomes present in the CSF, in patients with a high CSF lymphocyte count, and among patients in whom no trypanosomes were found in either the blood or the lymph node aspirate. Among patients with trypanosomes in the CSF, the risk of encephalopathy was similar whether or not they also had trypanosomes seen in the haemolymphatic system. Dimercaprol, a heavy metal chelator, did not reduce the case-fatality rate of patients with encephalopathy. These observations and others are compatible with the hypothesis that an immune phenomenon is involved in the pathogenesis of melarsoprol-induced encephalopathy. Whether the basic mechanism relates to deposits of immune complexes in the central nervous system or to the release of trypanosomal antigens which subsequently bind to brain cells and attract antibodies or T lymphocytes, the rapidity with which trypanosomal antigens are released may be critical, and very aggressive therapeutic schemes may result in higher toxicity, especially in patients with an impaired blood-brain barrier.
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Affiliation(s)
- J Pepin
- Medical Research Council Laboratories, Fajara, The Gambia
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Costa RS, Monteiro RC, Lehuen A, Joskowicz M, Noël LH, Droz D. Immune complex-mediated glomerulopathy in experimental Chagas' disease. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1991; 58:102-14. [PMID: 1824567 DOI: 10.1016/0090-1229(91)90152-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To investigate the development of glomerulopathy during the chronic phase of experimental Chagas' disease, C3H-Hej mice were infected with Trypanosoma cruzi trypomastigotes. Deposits of IgG, IgM, and C3 in renal mesangium were observed by immunofluorescence (IF) to increase in size as a function of time after infection (4-6 months). T. cruzi antigens were codeposited in glomeruli with Ig and C3. Electron-dense deposits were visualized in mesangial and paramesangial areas by electron microscopy. Anti-T. cruzi and rheumatoid factor (RF) antibodies (of IgG isotypes) were detected both in serum and in renal eluates. In serum, the titers of both antibodies progressively decreased as a function of time after infection. In renal eluates, titers of anti-T. cruzi antibodies appeared to be stable during the three time periods after infection. By contrast, titers of RF antibodies in renal eluates were shown to increase progressively during these same time periods, paralleling the increase in size of mesangial Ig deposits observed by IF. Several T. cruzi proteins were immunoprecipitated from radiolabeled renal eluates by a control anti-T. cruzi antibody. In addition, antibodies from renal eluates specifically precipitated a 85-kDa protein from radiolabeled T. cruzi lysates, whereas serum antibodies precipitated a broad pattern of T. cruzi proteins. These results demonstrate that mice experimentally infected with T. cruzi can develop a mesangial glomerulopathy during the chronic phase of the disease, which appears to be mediated through immune complexes containing parasite antigens associated with secondary deposition of RF.
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Affiliation(s)
- R S Costa
- INSERM U25, Hôpital Necker, Paris, France
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Abstract
The advanced stages of sleeping sickness are correlated with a spread of trypanosomes into the central nervous system (CNS), producing a disseminated encephalitis. Inflammatory reactions extend along the blood vessels causing perivascular cuffing, which consists of in filtrations and proliferations of lymphocytes and also increased numbers of astrocytes and microglia. Progress in our understanding of the functions of astrocytes suggests that they are efficient antigen-presenting cells, initiating and regulating the intracerebral inflammatory response and limiting parasite spread to the perivascular spaces.
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Affiliation(s)
- V W Pentreath
- Department of Biological Sciences, University of Salford, Salford M5 4WT, UK
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Spinazzola F, D'Amato C, De Felici A, Giannuzzi R, Paglia MG, Struglia C, Tocci G, Visco G, Galgani S, Cotroneo E. Plasmapheresis for late-stage trypanosomiasis. Lancet 1989; 1:1200. [PMID: 2566757 DOI: 10.1016/s0140-6736(89)92775-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Abstract
The presence of circulating immune complexes have been described in many different human disease states but the significance of their presence has always been a subject for debate. Improvements in the methods of detecting immune complexes have demonstrated a wide degree of heterogeneity, which accounts for the difficulty in obtaining accurate and reproducible measurements, even in the same individual. Techniques for isolating individual complexes, characterizing their pathophysiological properties, and biochemically analyzing the nature of the complexed antigen are now being used to provide data that is helping to clarify the role of immune complexes in the pathogenesis of disease. In addition, such studies are also providing data which is proving that immune complexes have a potential role in immune regulation.
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Affiliation(s)
- T M Phillips
- Department of Immunochemistry and Medicine, George Washington University Medical Center, Washington, D.C
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Affiliation(s)
- R W Leid
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040
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