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Roose S, Vande Velde F, Vlaminck J, Geldhof P, Levecke B. Serological diagnosis of soil-transmitted helminth (Ascaris, Trichuris and hookworm) infections: A scoping review. PLoS Negl Trop Dis 2024; 18:e0012049. [PMID: 38574166 PMCID: PMC10994556 DOI: 10.1371/journal.pntd.0012049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/05/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND The World Health Organization emphasizes the importance of integrated monitoring and evaluation in neglected tropical disease (NTD) control programs. Serological assays offer a potential solution for integrated diagnosis of NTDs, particularly for those requiring mass drug administration (MDA) as primary control and elimination strategy. This scoping review aims (i) to provide an overview of assays using serum or plasma to detect infections with soil-transmitted helminths (STHs) in both humans and animals, (ii) to examine the methodologies used in this research field and (iii) to discuss advancements in serological diagnosis of STHs to guide prevention and control programs in veterinary and human medicine. METHODOLOGY We conducted a systematic search in the Ovid MEDLINE, Embase and Cochrane Library databases, supplemented by a Google search using predefined keywords to identify commercially available serological assays. Additionally, we performed a patent search through Espacenet. PRINCIPAL FINDINGS We identified 85 relevant literature records spanning over 50 years, with a notable increased interest in serological assay development in recent years. Most of the research efforts concentrated on diagnosing Ascaris infections in both humans and pigs, primarily using ELISA and western blot technologies. Almost all records targeted antibodies as analytes, employing proteins and peptides as analyte detection agents. Approximately 60% of sample sets described pertained to human samples. No commercially available tests for Trichuris or hookworms were identified, while for Ascaris, there are at least seven different ELISAs on the market. CONCLUSIONS While a substantial number of assays are employed in epidemiological research, the current state of serological diagnosis for guiding STH prevention and control programs is limited. Only two assays designed for pigs are used to inform efficient deworming practices in pig populations. Regarding human diagnosis, none of the existing assays has undergone extensive large-scale validation or integration into routine diagnostics for MDA programs.
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Affiliation(s)
- Sara Roose
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Fiona Vande Velde
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Johnny Vlaminck
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Peter Geldhof
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
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Puchner KP, Bottazzi ME, Periago V, Grobusch M, Maizels R, McCarthy J, Lee B, Gaspari E, Diemert D, Hotez P. Vaccine value profile for Hookworm. Vaccine 2023:S0264-410X(23)00540-6. [PMID: 37863671 DOI: 10.1016/j.vaccine.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 04/24/2023] [Accepted: 05/03/2023] [Indexed: 10/22/2023]
Abstract
Hookworm, a parasitic infection, retains a considerable burden of disease, affecting the most underprivileged segments of the general population in endemic countries and remains one of the leading causes of mild to severe anemia in Low and Middle Income Countries (LMICs), particularly in pregnancy and children under 5. Despite repeated large scale Preventive Chemotherapy (PC) interventions since more than 3 decades, there is broad consensus among scholars that elimination targets set in the newly launched NTD roadmap will require additional tools and interventions. Development of a vaccine could constitute a promising expansion of the existing arsenal against hookworm. Therefore, we have evaluated the biological and implementation feasibility of the vaccine development as well as the added value of such a novel tool. Based on pipeline landscaping and the current knowledge on key biological aspects of the pathogen and its interactions with the host, we found biological feasibility of development of a hookworm vaccine to be moderate. Also, our analysis on manufacturing and regulatory issues as well as potential uptake yielded moderate implementation feasibility. Modelling studies suggest a that introduction of a vaccine in parallel with ongoing integrated interventions (PC, WASH, shoe campaigns), could substantially reduce burden of disease in a cost - saving mode. Finally a set of actions are recommended that might impact positively the likelihood of timely development and introduction of a hookworm vaccine.
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Affiliation(s)
| | - Maria Elena Bottazzi
- National School of Tropical Medicine, Baylor College of Medicine, Baylor, TX, USA
| | | | - Martin Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, Location AMC, Amsterdam Infection & Immunity, Amsterdam Public Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Rick Maizels
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - James McCarthy
- The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Bruce Lee
- Public Health Informatics, Computational, and Operations Research, Graduate School of Public Health and Health Policy, City University of New York, New York, NY, USA
| | - Erika Gaspari
- European & Developing Countries Clinical Trials Partnership (EDCTP), The Hague, The Netherlands
| | - David Diemert
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University Medical Center, Washington, DC, USA
| | - Peter Hotez
- National School of Tropical Medicine, Baylor College of Medicine, Baylor, TX, USA
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3
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Roose S, Leta GT, Vlaminck J, Getachew B, Mekete K, Peelaers I, Geldhof P, Levecke B. Comparison of coproprevalence and seroprevalence to guide decision-making in national soil-transmitted helminthiasis control programs: Ethiopia as a case study. PLoS Negl Trop Dis 2022; 16:e0010824. [PMID: 36197895 PMCID: PMC9534397 DOI: 10.1371/journal.pntd.0010824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/16/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND WHO recommends periodical assessment of the prevalence of any soil-transmitted helminth (STH) infections to adapt the frequency of mass drug administration targeting STHs. Today, detection of eggs in stool smears (Kato-Katz thick smear) remains the diagnostic standard. However, stool examination (coprology) has important operational drawbacks and impedes integrated surveys of multiple neglected tropical diseases. Therefore, the aim of the present study was to assess the potential of applying serology instead of coprology in STH control program decision-making. METHODOLOGY An antibody-ELISA based on extract of Ascaris lung stage larvae (AsLungL3-ELISA) was applied in ongoing monitoring activities of the Ethiopian national control program against schistosomiasis and soil-transmitted helminthiasis. Blood and stool samples were collected from over 6,700 students (median age: 11) from 63 schools in 33 woredas (districts) across the country. Stool samples of two consecutive days were analyzed applying duplicate Kato-Katz thick smear. PRINCIPAL FINDINGS On woreda level, qualitative (seroprevalence) and quantitative (mean optical density ratio) serology results were highly correlated, and hence seroprevalence was chosen as parameter. For 85% of the woredas, prevalence based on serology was higher than those based on coprology. The results suggested cross-reactivity of the AsLungL3-ELISA with Trichuris. When extrapolating the WHO coproprevalence thresholds, there was a moderate agreement (weighted κ = 0.43) in program decision-making. Using the same threshold values would predominantly lead to a higher frequency of drug administration. SIGNIFICANCE This is the first time that serology for soil-transmitted helminthiasis is applied on such large scale, thereby embedded in a control program context. The results underscore that serology holds promise as a tool to monitor STH control programs. Further research should focus on the optimization of the diagnostic assay and the refinement of serology-specific program decision-making thresholds.
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Affiliation(s)
- Sara Roose
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
- * E-mail: (SR); (BL)
| | - Gemechu Tadesse Leta
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Johnny Vlaminck
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Birhanu Getachew
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Kalkidan Mekete
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Iris Peelaers
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Peter Geldhof
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
- * E-mail: (SR); (BL)
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Meza Cerda MI, Gray R, Thomson PC, Butcher L, Simpson K, Cameron A, Marcus AD, Higgins DP. Developing Immune Profiles of Endangered Australian Sea Lion ( Neophoca cinerea) Pups Within the Context of Endemic Hookworm ( Uncinaria sanguinis) Infection. Front Vet Sci 2022; 9:824584. [PMID: 35529837 PMCID: PMC9069138 DOI: 10.3389/fvets.2022.824584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
As a top predator, the endangered Australian sea lion (Neophoca cinerea) is a sentinel of ecosystem change, where population trends can reflect broader shifts in the marine environment. The population of this endemic pinniped was historically diminished by commercial sealing, and recovery has been slowed by fishery interactions, disease and, potentially, pollutants. Hookworm infects 100% of neonatal pups and has been identified as a contributor to population decline. Here, a multivariable approach using traditional serological and novel molecular tools such as qPCR and ddPCR was used to examine immune phenotypes of developing Australian sea lion pups infected with the endemic hookworm (Uncinaria sanguinis) from two South Australian colonies. Results show changing immunophenotypes throughout the patent period of infection represented by pro-inflammatory cytokines (IL-6), IgG and acute-phase proteins. Although cytokines may prove useful as markers of resistance, in this study, IL-6 is determined to be an early biomarker of inflammation in Australian sea lion pups, excluding the alternative hypothesis. Additionally, immunological differences between animals from high- and low-intensity hookworm seasons, as well as ivermectin-treated animals, indicate hookworm infection modulation of the host immune response, as evidenced by a lower IL-6 mRNA expression in the non-treated groups. This study of the Australian sea lion is an example of an ecoimmunological approach to disease investigation, which can be applied to evaluate the impact of environmental and anthropogenic factors on susceptibility to infectious diseases in free-ranging species
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Affiliation(s)
- María-Ignacia Meza Cerda
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Rachael Gray
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Peter C Thomson
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Loreena Butcher
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Kelly Simpson
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Abby Cameron
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Alan D Marcus
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Damien P Higgins
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
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Bungiro RD, Harrison LM, Dondji B, Cappello M. Comparison of percutaneous vs oral infection of hamsters with the hookworm Ancylostoma ceylanicum: Parasite development, pathology and primary immune response. PLoS Negl Trop Dis 2022; 16:e0010098. [PMID: 34986139 PMCID: PMC8765627 DOI: 10.1371/journal.pntd.0010098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/18/2022] [Accepted: 12/15/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Hundreds of millions of people in poor countries continue to suffer from disease caused by bloodfeeding hookworms. While mice and rats are not reliably permissive hosts for any human hookworm species, adult Golden Syrian hamsters are fully permissive for the human and animal pathogen Ancylostoma ceylanicum. Similar to humans, hamsters may be infected with A. ceylanicum third-stage larvae orally or percutaneously. Oral infection typically leads to consistent worm yields in hamsters but may not accurately reflect the clinical and immunological manifestations of human infection resulting from skin penetration. METHODOLOGY/PRINCIPAL FINDINGS In this study we compared host responses following percutaneous infection to those utilizing an established oral infection protocol. Infected hamsters exhibited a dose-dependent pathology, with 1000 percutaneous larvae (L3) causing anemia and adult worm recovery comparable to that of 50 orally administered L3. A delayed arrival and maturity of worms in the intestine was observed, as was variation in measured cellular immune responses. A long-term study found that the decline in blood hemoglobin was more gradual and did not reach levels as low, with the nadir of disease coming later in percutaneously infected hamsters. Both groups exhibited moderate growth delay, an effect that was more persistent in the percutaneously infected group. Fecal egg output also peaked later and at lower levels in the percutaneously infected animals. In contrast to orally infected hamsters, antibody titers to larval antigens continued to increase throughout the course of the experiment in the percutaneous group. CONCLUSIONS/SIGNIFICANCE These results demonstrate that the route of infection with A. ceylanicum impacts disease pathogenesis, as well as humoral and cellular immune responses in an experimental setting. These data further validate the utility of the Golden Syrian hamster as a model of both oral and percutaneous infection with human hookworms.
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Affiliation(s)
- Richard D. Bungiro
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Lisa M. Harrison
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Blaise Dondji
- Laboratory of Cellular Immunology and Parasitology, Department of Biological Sciences, Central Washington University, Ellensburg, Washington, United States of America
| | - Michael Cappello
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America
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Shalash AO, Hussein WM, Skwarczynski M, Toth I. Hookworm infection: Toward development of safe and effective peptide vaccines. J Allergy Clin Immunol 2021; 148:1394-1419.e6. [PMID: 34872650 DOI: 10.1016/j.jaci.2021.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/07/2021] [Accepted: 10/18/2021] [Indexed: 11/28/2022]
Abstract
Hookworms are hematophagous nematode parasites that have infected a billion people worldwide. Anthelmintic drugs have limited efficacy and do not prevent reinfection. Therefore, prophylactic vaccines are in high demand. Whole parasite vaccines are allergic and unsafe; thus, research into subunit vaccines has been warranted. A comprehensive overview of protein or peptide subunit vaccines' safety, protective efficacy, and associated immune responses is provided herein. The differences between the immune responses against hookworm infection by patients from epidemic versus nonepidemic areas are discussed in detail. Moreover, the different immunologic mechanisms of protection are discussed, including those that rely on allergic and nonallergic humoral and antibody-dependent cellular responses. The allergic and autoimmune potential of hookworm antigens is also explored, as are the immunoregulatory responses induced by the hookworm secretome. The potential of oral mucosal immunizations has been overlooked. Oral immunity against hookworms is a long-lived and safer immune response that is associated with elimination of infection and protective against reinfections. However, the harsh conditions of the gastrointestinal environment necessitates special oral delivery systems to unlock vaccines' protective potential. The potential for development of safer and more effective peptide- and protein-based anthelmintic vaccines is explored herein.
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Affiliation(s)
- Ahmed O Shalash
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Waleed M Hussein
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Mariusz Skwarczynski
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Queensland, Australia.
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Komnenou AT, Gkafas GA, Kofidou E, Sarantopoulou J, Exadactylos A, Tounta E, Koemtzopoulos K, Dendrinos P, Karamanlidis AA, Gulland F, Papadopoulos E. First Report of Uncinaria hamiltoni in Orphan Eastern Mediterranean Monk Seal Pups in Greece and Its Clinical Significance. Pathogens 2021; 10:pathogens10121581. [PMID: 34959536 PMCID: PMC8708642 DOI: 10.3390/pathogens10121581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
The Mediterranean monk seal (Monachus monachus) is classified by the IUCN as “endangered,” with a global population estimated to number fewer than 800 individuals. Our understanding of the biology and health status of the species is still limited, rendering every medical case a challenge for conservationists and veterinary clinicians. Although studying and managing disease in wild marine hosts is complex and challenging, studying and mitigating the effects of any disease to the Mediterranean monk seal is of utmost importance for conservation. The aim of this study was to document for the first time the presence of the hookworm Uncinaria hamiltoni in rehabilitated Mediterranean monk seal pups in Greece. A detailed examination protocol was followed for all pups that live-stranded over 30 years in 22 different locations, including physical, parasitological, and other examinations. Hookworms (adults and/or eggs) were detected in all the fecal samples, from all animals. Molecular identification using MtDNA (COI) and ribosomal DNA (D2/D3 28S and internal transcribed spacer [ITS] regions) identified the nematode species as Uncinaria hamiltoni. The clinical impacts and the benefits of anthelmintic treatment as a tool for the conservation management of the species are discussed.
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Affiliation(s)
- Anastasia Th. Komnenou
- School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece; (A.T.K.); (E.K.)
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - George A. Gkafas
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece; (G.A.G.); (J.S.); (A.E.)
| | - Evangelia Kofidou
- School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece; (A.T.K.); (E.K.)
| | - Joanne Sarantopoulou
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece; (G.A.G.); (J.S.); (A.E.)
| | - Athanasios Exadactylos
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece; (G.A.G.); (J.S.); (A.E.)
| | - Eleni Tounta
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Kimon Koemtzopoulos
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Panagiotis Dendrinos
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Alexandros A. Karamanlidis
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Frances Gulland
- Karen C. Drayer Wildlife Heath Center, School of Veterinary Medicine, University of California, Davis, CA 95616, USA;
- Marine Mammal Commission, Bethesda, MD 20814, USA
| | - Elias Papadopoulos
- School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece; (A.T.K.); (E.K.)
- Correspondence: ; Tel.: +30-6944882872
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Chapman PR, Giacomin P, Loukas A, McCarthy JS. Experimental human hookworm infection: a narrative historical review. PLoS Negl Trop Dis 2021; 15:e0009908. [PMID: 34882670 PMCID: PMC8659326 DOI: 10.1371/journal.pntd.0009908] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In 1896, a serendipitous laboratory accident led to the understanding that hookworms propagate infection by penetrating skin, a theory that was then confirmed with the first experimental human infection, reported in 1901. Experimental human infections undertaken in the 20th century enabled understanding of the natural history of infection and the immune response. More recently, experimental hookworm infection has been performed to investigate the immunomodulatory potential of hookworm infection and for the evaluation of hookworm vaccines and chemotherapeutic interventions. Experimental human hookworm infection has been proven to be safe, with no deaths observed in over 500 participants (although early reports predate systematic adverse event reporting) and no serious adverse events described in over 200 participants enrolled in contemporary clinical trials. While experimental human hookworm infection holds significant promise, as both a challenge model for testing anti-hookworm therapies and for treating various diseases of modernity, there are many challenges that present. These challenges include preparation and storage of larvae, which has not significantly changed since Harada and Mori first described their coproculture method in 1955. In vitro methods of hookworm larval culture, storage, and the development of meaningful potency or release assays are required. Surrogate markers of intestinal infection intensity are required because faecal egg counts or hookworm faecal DNA intensity lack the fidelity required for exploration of hookworm infection as a vaccine/drug testing platform or as a regulated therapy.
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Affiliation(s)
- Paul R. Chapman
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, Australia
- Infectious Diseases Unit, Royal Brisbane and Women’s Hospital, Herston, Australia
| | - Paul Giacomin
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - James S. McCarthy
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, Australia
- Infectious Diseases Unit, Royal Brisbane and Women’s Hospital, Herston, Australia
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9
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Taghipour A, Ghodsian S, Jabbari M, Olfatifar M, Abdoli A, Ghaffarifar F. Global prevalence of intestinal parasitic infections and associated risk factors in pregnant women: a systematic review and meta-analysis. Trans R Soc Trop Med Hyg 2021; 115:457-470. [PMID: 33007067 DOI: 10.1093/trstmh/traa101] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/04/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Intestinal parasitic infections (IPIs) during pregnancy, if left untreated, can cause adverse effects for the mothers, foetuses and newborns. However, limited information is available about the global status of IPIs in pregnant women. Here we undertook a meta-analysis to estimate the global prevalence of IPIs and associated risk factors in pregnant women. METHODS We searched the PubMed, Science Direct, Scopus, Web of Science and Google Scholar databases for relevant studies that were published between 1 January 1987 and 30 December 2019. A random effects meta-analysis model was used to estimate the pooled prevalence, odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS A total of 114 studies comprising 98 342 pregnant women across 35 countries were included in the systematic review and meta-analysis. Among IPIs identified from pregnant women, three helminth infections (hookworm 19% [95% CI 15 to 23], Ascaris lumbricoides 17% [95% CI 13 to 21] and Trichuris trichiura 11% [95% CI 7 to 16]) and three protozoan infections (Blastocystis sp. 21% [95% CI 4 to 46], Entamoeba histolytica/dispar 9% [95% CI 3 to 19] and Giardia sp. 8% [95% CI 4 to 13]) were identified as the most prevalent intestinal parasites. Moreover, we found that there was a significant association between IPIs with increased risk of anaemia in pregnant women (OR 2.65 [95% CI 2.08 to 3.37]). The prevalence of IPIs was slightly higher in geophagic pregnant women compared with controls, but this was not significant (OR 1.22 [95% CI 0.87 to 1.71]). According to species, the pooled OR of A. lumbricoides infection had a significantly higher risk in geophagic pregnant women compared with controls (OR 2.66 [95% CI 1.37 to 5.16]). There was a positive relationship between the high prevalence of IPIs in pregnant women living in rural areas compared with urban residents (OR 3.36 [95% CI 1.57 to 7.19]). CONCLUSIONS The current review revealed a relatively high prevalence of IPIs in pregnant women, especially in some low- and middle-income countries. These results suggest a need for improved prevention and control efforts to reduce the health risks to pregnant women.
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Affiliation(s)
- Ali Taghipour
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, P.O. Box 14115-111, Tehran, Iran
| | - Sahar Ghodsian
- Department of Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahdi Jabbari
- Department of Microbiology, Faculty of Basic Science, Tabriz Branch, Islamic Azad University, Tabriz, Iran
| | - Meysam Olfatifar
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Abdoli
- Department of Parasitology and Mycology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.,Zoonoses Research Center, Jahrom University of Medical Sciences, Jahrom, Iran
| | - Fatemeh Ghaffarifar
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, P.O. Box 14115-111, Tehran, Iran
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Vlaminck J, Lagatie O, Dana D, Mekonnen Z, Geldhof P, Levecke B, Stuyver LJ. Identification of antigenic linear peptides in the soil-transmitted helminth and Schistosoma mansoni proteome. PLoS Negl Trop Dis 2021; 15:e0009369. [PMID: 33909616 PMCID: PMC8081252 DOI: 10.1371/journal.pntd.0009369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/07/2021] [Indexed: 11/18/2022] Open
Abstract
The scientific community identified non stool-based biomarkers as the way forward to support soil-transmitted helminth (STH; Ascaris lumbricoides, Trichuris trichiura and the hookworms Ancylostoma duodenale and Necator americanus) and schistosome (S. mansoni and S. haematobium) deworming programs. This support is needed in making the decision of whether or not to stop preventive chemotherapy intervention efforts and to ultimately transition towards a post-intervention surveillance phase. We applied a two-step micro-array approach to identify antigenic linear epitopes in the STH and S. mansoni proteomes. In a first experiment, we identified antigenic peptides by applying sera from 24 STH and/or S. mansoni infected Ethiopian children on a high-density peptide microarray containing 3.3 million peptides derived from the complete STH and S. mansoni proteomes. A second array experiment with 170,185 peptides that were recognized in the first array was designed to identify non-specific antibody reactivity by applying sera from 24 healthy individuals from Belgium (a non-endemic country). From this array testing cascade, several peptides were identified for STH but none of them appeared to be unique for one species. We therefore concluded that for STH, none of the peptides revealed to be sufficiently sensitive or species specific. For S. mansoni, some promising peptides were identified prompting future investigation. Based on these results, it is unlikely that linear epitopes would be highly useful in detecting species-specific antibody responses to STH in endemic communities. For S. mansoni, one particular peptide of the micro-exon gene 12 (MEG-12) protein deserves further research. In addition, this study emphasizes the need of well-characterized biobanks for biomarker discovery, particularly when the integration of multiple disease programs is envisioned. Today, infections with intestinal (roundworms, whipworm and hookworms) and blood-dwelling worms (schistosomes) are traditionally diagnosed by demonstrating worm eggs in stool. This current practice comes with some important challenges, including but not limited to the low-throughput and the need of skilled operators. Especially in the context of monitoring and evaluation, there is a need for alternative tools. Therefore, one of the recommendations of the scientific community was to develop tests that are based on the detection of antibodies in blood, which reflect the natural immune response of the host to worm-specific components or antigens. In the present study, we screened the antigenicity of all the peptides that build up the proteome of intestinal and blood-dwelling worms. For intestinal worms, our results revealed that the antibody response to these peptides was either not unique for the worm species or absent in infected subjects. For blood-dwelling worms, the findings were less sobering, with a number of peptides inducing an antibody response that was only observed in infected subjects.
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Affiliation(s)
- Johnny Vlaminck
- Department of Virology, Parasitology, Immunology and Physiology, Ghent University, Merelbeke, Belgium
| | - Ole Lagatie
- Global Public Health R&D, Janssen Pharmaceutica NV, Beerse, Belgium
- * E-mail:
| | - Daniel Dana
- Department of Virology, Parasitology, Immunology and Physiology, Ghent University, Merelbeke, Belgium
- School of Laboratory Science, Faculty of health science, Institute of health, Jimma University, Jimma, Ethiopia
| | - Zeleke Mekonnen
- School of Laboratory Science, Faculty of health science, Institute of health, Jimma University, Jimma, Ethiopia
| | - Peter Geldhof
- Department of Virology, Parasitology, Immunology and Physiology, Ghent University, Merelbeke, Belgium
| | - Bruno Levecke
- Department of Virology, Parasitology, Immunology and Physiology, Ghent University, Merelbeke, Belgium
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Mourão Dias Magalhães L, Silva Araújo Passos L, Toshio Fujiwara R, Lacerda Bueno L. Immunopathology and modulation induced by hookworms: From understanding to intervention. Parasite Immunol 2020; 43:e12798. [PMID: 33012113 DOI: 10.1111/pim.12798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/21/2020] [Accepted: 09/25/2020] [Indexed: 12/15/2022]
Abstract
Hookworm infection is considered the most prevalent human soil-transmitted helminth infection affecting approximately 500 million people and accounting for 3.2 million disability-adjusted life years lost annually. As with many other neglected tropical diseases, no international surveillance mechanisms that show accurate data on the prevalence of hookworm infection are in place, thus hindering strategies to control parasite transmission. In this review, we unravel the current knowledge in immunopathology and immunoregulation of hookworm infection and present discoveries in drug therapies based on the capability of hookworms to regulate inflammation to treat allergic, inflammatory and metabolic diseases. Additionally, we highlight potential vaccine development and treatments and propose avenues for further inquiry.
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Affiliation(s)
| | - Livia Silva Araújo Passos
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo Toshio Fujiwara
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Lilian Lacerda Bueno
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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12
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Epidemiological aspects of Ancylostoma spp. infection in naturally infected dogs from São Paulo state, Brazil. VETERINARY PARASITOLOGY- REGIONAL STUDIES AND REPORTS 2020; 22:100452. [PMID: 33308717 DOI: 10.1016/j.vprsr.2020.100452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 04/30/2020] [Accepted: 08/16/2020] [Indexed: 11/21/2022]
Abstract
Ancylostoma spp. are the most prevalent canine nematode parasites in Brazil. Despite their widespread parasitism in juvenile dogs, infections may occur regardless of host age. Although eosinophilia is a frequent finding in experimental infections, it is uncommon in naturally infected dogs. This study aimed to evaluate the prevalence of Ancylostoma spp. and the eosinophil blood counts (EBC) in naturally infected dogs, with or without comorbidities, admitted to the Veterinary Teaching Hospital of the São Paulo State University (UNESP), School of Veterinary Medicine and Animal Science, Botucatu campus, São Paulo state, Brazil, from 2009 to 2018. All retrospective data were gathered from veterinary medical records (VMR); diagnosis of Ancylostoma infection required the identification of eggs in fecal samples by the simple flotation test (SFT). Ancylostoma-infected animals were evaluated for other intestinal parasitic coinfections (IPC) by either the SFT or the centrifugal-flotation test. Dogs free of any gastro-intestinal parasites were prospectively included in control group (Group C). Ancylostoma-infected animals were defined: Ancylostoma spp. only intestinal parasite infection (Group A), Ancyslostoma spp. with concurrent IPC (Group B), Ancylostoma spp. only intestinal parasite infection with concurrent systemic disorders (Group D), and Ancylostoma spp. with both IPC and concurrent systemic disorders (Group E). The overall prevalence of Ancylostoma spp. was 12.1% (207/1715), that was decreased from 2014 to 2018 (9.7%) relative to the 2009-to-2013 period (13.9%). Prevalence was not significantly different between dogs <1-year-old (10.7% [51/478]) and ≥ 1 year-old (11.7% [130/1109]). IPC was observed in 45.4% (93/205) of the animals positive for Ancylostoma spp., while dogs <1 year old experienced IPC more often (58.8% [30/51]) than dogs ≥1 year old (38.5% [50/130]) (P = 0.02). Group A (n = 35) exhibited median EBC of 1.05 × 109/L, and an eosinophilia ratio of 34.3% that was significantly higher (P < 0.05) than Group C (0.45 × 109/L and 4.1%, respectively). Both variables did not differ in Group B (n = 20), D (n = 39) or E (n = 36) in comparison to Group C (P > 0.05). By ROC curve analysis, only Group A generated a significant area under the curve (0.72). With EBC cutoff of 0.85 × 109 eosinophils/L, sensitivity and specificity were 65.7% and 70.8%, respectively. Eosinophil counts alone may be helpful in raising suspicion of an Ancylostoma spp. infection if further intestinal parasites and concurrent disorders are absent. However, local prevalence data and epidemiological findings should also be evaluated, since eosinophilia is less frequently observed with Ancylostoma spp. infections in the presence of comorbidities.
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Seltmann A, Webster F, Martins Ferreira SC, Czirják GÁ, Wachter B. Age-specific gastrointestinal parasite shedding in free-ranging cheetahs (Acinonyx jubatus) on Namibian farmland. Parasitol Res 2019; 118:851-859. [PMID: 30706167 DOI: 10.1007/s00436-018-6190-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 12/19/2018] [Indexed: 11/29/2022]
Abstract
The cheetah (Acinonyx jubatus Brookes 1828) is classified as "vulnerable" by the International Union for Conservation of Nature (IUCN). Threats to cheetah populations are a decrease of suitable habitats, an increase of conflicts with livestock farmers and potentially pathogens. While there is some information on the viral and bacterial pathogens circulating in cheetah populations, information on gastrointestinal parasites is scarce. Here, we investigate the gastrointestinal parasites in 39 free-ranging cheetahs in east-central Namibia using a coproscopical parasitological method. Most cheetahs (82%) shed eggs from Ancylostoma which comprised the majority of the total eggs in feces. Eggs and oocysts from Toxascaris (21% of cheetahs), Coccidia (13%), Physaloptera (8%), Taeniidae (5%), Dipylidium (3%), and Diphyllobothriidae (3%) were present at a lower prevalence. Parasite richness and Ancylostoma egg load were higher in juveniles and adults compared to cubs, but were not associated with sex. To our knowledge, this is the first study that assessed gastrointestinal parasites in free-ranging cheetahs and is a key starting point for future studies on the effect of parasites in this threatened species.
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Affiliation(s)
- Anne Seltmann
- Department of Wildlife Diseases / Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.
| | - Fay Webster
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | | | - Gábor Árpád Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Bettina Wachter
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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Bacillus thuringiensis Cry5B protein as a new pan-hookworm cure. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:287-294. [PMID: 29772478 PMCID: PMC6039361 DOI: 10.1016/j.ijpddr.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/27/2018] [Accepted: 05/03/2018] [Indexed: 11/20/2022]
Abstract
Hookworms are intestinal nematode parasites that infect nearly half a billion people and are globally one of the most important contributors to iron-deficiency anemia. These parasites have significant impacts in developing children, pregnant women and working adults. Of all the soil-transmitted helminths or nematodes (STNs), hookworms are by far the most important, with disease burdens conservatively estimated at four million DALYs (Disability-Adjusted Life Years) and with productivity losses of up to US$139 billion annually. To date, mainly one drug, albendazole is used for hookworm therapy in mass drug administration, which has on average ∼80% cure rate that is lower (<40%) in some places. Given the massive numbers of people needing treatment, the threat of parasite resistance, and the inadequacy of current treatments, new and better cures against hookworms are urgently needed. Cry5B, a pore-forming protein produced by the soil bacterium Bacillus thuringiensis (Bt) has demonstrated good efficacy against Ancylostoma ceylanicum hookworm infections in hamsters. Here we broaden studies of Cry5B to include tests against infections of Ancylostoma caninum hookworms in dogs and against infections of the dominant human hookworm, Necator americanus, in hamsters. We show that Cry5B is highly effective against all hookworm parasites tested in all models. Neutralization of stomach acid improves Cry5B efficacy, which will aid in practical application of Cry5B significantly. Importantly, we also demonstrate that the anti-nematode therapeutic efficacy of Cry5B is independent of the host immune system and is not itself negated by repeated dosing. This study indicates that Bt Cry5B is a pan-hookworm anthelmintic with excellent properties for use in humans and other animals.
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Bouchery T, Volpe B, Shah K, Lebon L, Filbey K, LeGros G, Harris N. The Study of Host Immune Responses Elicited by the Model Murine HookwormsNippostrongylus brasiliensisandHeligmosomoides polygyrus. ACTA ACUST UNITED AC 2018; 7:236-286. [DOI: 10.1002/cpmo.34] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- T. Bouchery
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
| | - B. Volpe
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
| | - K. Shah
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
| | - L. Lebon
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
| | - K. Filbey
- Malaghan Institute of Medical Research; Wellington New Zealand
| | - G. LeGros
- Malaghan Institute of Medical Research; Wellington New Zealand
| | - N. Harris
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
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Shepherd C, Wangchuk P, Loukas A. Of dogs and hookworms: man's best friend and his parasites as a model for translational biomedical research. Parasit Vectors 2018; 11:59. [PMID: 29370855 PMCID: PMC5785905 DOI: 10.1186/s13071-018-2621-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/03/2018] [Indexed: 02/06/2023] Open
Abstract
We present evidence that the dog hookworm (Ancylostoma caninum) is underutilised in the study of host-parasite interactions, particularly as a proxy for the human-hookworm relationship. The inability to passage hookworms through all life stages in vitro means that adult stage hookworms have to be harvested from the gut of their definitive hosts for ex vivo research. This makes study of the human-hookworm interface difficult for technical and ethical reasons. The historical association of humans, dogs and hookworms presents a unique triad of positive evolutionary pressure to drive the A. caninum-canine interaction to reflect that of the human-hookworm relationship. Here we discuss A. caninum as a proxy for human hookworm infection and situate this hookworm model within the current research agenda, including the various 'omics' applications and the search for next generation biologics to treat a plethora of human diseases. Historically, the dog hookworm has been well described on a physiological and biochemical level, with an increasing understanding of its role as a human zoonosis. With its similarity to human hookworm, the recent publications of hookworm genomes and other omics databases, as well as the ready availability of these parasites for ex vivo culture, the dog hookworm presents itself as a valuable tool for discovery and translational research.
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Affiliation(s)
- Catherine Shepherd
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia.
| | - Phurpa Wangchuk
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia.
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Passos LSA, Gazzinelli-Guimarães PH, Oliveira Mendes TAD, Guimarães ACG, Silveira Lemos DD, Ricci ND, Gonçalves R, Bartholomeu DC, Fujiwara RT, Bueno LL. Regulatory monocytes in helminth infections: insights from the modulation during human hookworm infection. BMC Infect Dis 2017; 17:253. [PMID: 28390393 PMCID: PMC5385058 DOI: 10.1186/s12879-017-2366-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 03/29/2017] [Indexed: 12/25/2022] Open
Abstract
Background While the macrophage polarization is well characterized in helminth infections, the natural heterogeneity of monocytes with multiple cell phenotypes might influence the outcome of neglected diseases, such hookworm infection. Here, we report the profile of monocytes in human hookworm infections as a model to study the regulatory subpopulation of monocytes in helminth infections. Methods Blood samples were collected from 19 Necator americanus-infected individuals and 13 healthy individuals. Peripheral blood mononuclear cells (PBMCs) were isolated, and immunophenotyping was conducted by flow cytometry. The expressions of genes encoding human nitric oxide synthase (iNOS), interleukin 4 (IL-4), arginase-1 (Arg-1) and glyceraldehyde 3-phosphate dehydrogenase were quantified by qPCR. Plasma levels of IL-4 were determined by sandwich ELISA. Unpaired t-tests or Mann-Whitney tests were used depending on the data distribution. Results Hookworm infected individuals (HWI) showed a significant increase in the number of monocytes/mm3 (555.2 ± 191.0) compared to that of the non-infected (NI) individuals (120.4 ± 44.7) (p < 0.0001). While the frequencies of CD14+IL-10+ and CD14+IL-12+ cells were significantly reduced in the HWI compared to NI group (p = 0.0289 and p < 0.0001, respectively), the ratio between IL-10/IL-12 producing monocytes was significantly elevated in HWI (p = 0.0004), indicating the potential regulatory activity of these cells. Measurement of IL-4 levels and gene expression of IL-4 and Arg-1 (highly expressed in alternatively activated macrophages) revealed no significant differences between the NI and HWI groups. Interestingly, individuals from the HWI group had higher expression of the iNOS gene (associated with a regulatory profile) (20.27 ± 2.97) compared to the NI group (11.28 ± 1.18, p = 0.0409). Finally, individuals from the HWI group had a significantly higher frequency of CD206+CD23+IL-10+ (7.57 ± 1.96) cells compared to individuals from the NI group (0.35 ± 0.09) (p < 0.001), suggesting that activated monocytes are a potential source of regulatory cytokines during hookworm infection. Conclusions Natural hookworm infection induces a high frequency of circulating monocytes that present a regulatory profile and promote the downmodulation of the proinflammatory response, which may contribute to prolonged survival of the parasite in the host.
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Affiliation(s)
- Lívia Silva Araújo Passos
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Pedro Henrique Gazzinelli-Guimarães
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Ana Clara Gazzinelli Guimarães
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Denise da Silveira Lemos
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Natasha Delaqua Ricci
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ricardo Gonçalves
- Department of General Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniella Castanheira Bartholomeu
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ricardo Toshio Fujiwara
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lilian Lacerda Bueno
- Department of Parasitology, Laboratory of Immunology and Genomics of Parasites, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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Brelsford JB, Plieskatt JL, Yakovleva A, Jariwala A, Keegan BP, Peng J, Xia P, Li G, Campbell D, Periago MV, Correa-Oliveira R, Bottazzi ME, Hotez PJ, Diemert D, Bethony JM. Advances in neglected tropical disease vaccines: Developing relative potency and functional assays for the Na-GST-1/Alhydrogel hookworm vaccine. PLoS Negl Trop Dis 2017; 11:e0005385. [PMID: 28192438 PMCID: PMC5325600 DOI: 10.1371/journal.pntd.0005385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 02/24/2017] [Accepted: 02/04/2017] [Indexed: 11/19/2022] Open
Abstract
A new generation of vaccines for the neglected tropical diseases (NTDs) have now advanced into clinical development, with the Na-GST-1/Alhydrogel Hookworm Vaccine already being tested in Phase 1 studies in healthy adults. The current manuscript focuses on the often overlooked critical aspects of NTD vaccine product development, more specifically, vaccine stability testing programs. A key measure of vaccine stability testing is "relative potency" or the immunogenicity of the vaccine during storage. As with most NTD vaccines, the Na-GST-1/Alhydrogel Hookworm Vaccine was not developed by attenuation or inactivation of the pathogen (Necator americanus), so conventional methods for measuring relative potency are not relevant for this investigational product. Herein, we describe a novel relative potency testing program and report for the first time on the clinical lot of this NTD vaccine during its first 60 months of storage at 2–8°C. We also describe the development of a complementary functional assay that measures the ability of IgG from animals or humans immunized with Na-GST-1/Alhydrogel to neutralize this important hookworm enzyme. While 90% inhibition of the catalytic activity of Na-GST-1 was achieved in animals immunized with Na-GST-1/Alhydrogel, lower levels of inhibition were observed in immunized humans. Moreover, anti-Na-GST-1 antibodies from volunteers in non-hookworm endemic areas were better able to inhibit catalytic activity than anti-Na-GST-1 antibodies from volunteers resident in hookworm endemic areas. The results described herein provide the critical tools for the product development of NTD vaccines. As vaccines targeting NTDs advance into clinical trials, product development and vaccine maintenance become critical activities for the success of these vaccines. A key activity during this phase of vaccine development is the “relative potency” of a vaccine or the quality of the immune response that the vaccine elicits in an animal model during storage to ensure its immunogenicity is maintained. As with most NTD vaccines, the Na-GST-1/Alhydrogel Hookworm Vaccine was not developed using traditional methods of attenuating the pathogen (Necator americanus), so traditional measures of relative potency, such as testing the vaccine’s ability to protect against lethal challenge, could not be used. For the first time, we describe the development of a relative potency testing program for an NTD vaccine during five years of storage at 2–8°C. We also describe the development of a complementary functional assay that measures the ability of IgG from animals or humans immunized with Na-GST-1/Alhydrogel to neutralize this important hookworm enzyme. The results described herein provide, for the first time in an open access format, critical tools for the development of future NTD vaccines.
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Affiliation(s)
- Jill B. Brelsford
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Jordan L. Plieskatt
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Anna Yakovleva
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Amar Jariwala
- Department of Pathology, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Brian P. Keegan
- Department of Pediatrics, Section of Pediatric Tropical Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, United States of America
| | - Jin Peng
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Pengjun Xia
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Guangzhao Li
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Doreen Campbell
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | | | | | - Maria Elena Bottazzi
- Department of Pathology, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States of America
| | - Peter J. Hotez
- Department of Pathology, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States of America
| | - David Diemert
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
| | - Jeffrey M. Bethony
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University, Washington DC, United States of America
- * E-mail:
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Seguel M, Muñoz F, Navarrete MJ, Paredes E, Howerth E, Gottdenker N. Hookworm Infection in South American Fur Seal ( Arctocephalus australis) Pups. Vet Pathol 2016; 54:288-297. [PMID: 28207376 DOI: 10.1177/0300985816677151] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tissues of South American fur seal pups naturally infected with hookworms ( Uncinaria sp) were examined. Hookworm infection was found in nearly all pups examined (132/140, 94%), and hookworm enteritis with secondary bacteremia was considered the cause of death in 46 (35%) pups. Common findings in these pups included severe hemorrhagic enteritis and numerous (mean intensity = 761.8) hookworms in the jejunum. Hookworms were recovered from the abdominal cavity in 12 of 55 pups (22%) examined through peritoneal wash; these pups had an average of 1343.3 intestinal hookworms and marked fibrinohemorrhagic peritonitis. In all pups that died as a consequence of hookworm infection, the intestinal villi were short, blunt, and fused, and there were variable numbers of free and intrahistiocytic gram-negative bacteria in submucosal hookworm feeding tracks, mesenteric lymph nodes, spleen, blood vessels, and liver sinusoids. Pups that died of causes unrelated to the hookworm infection (trauma) had hookworm feeding tracks confined to the apical portions of the mucosa, and moderate to marked catarrhal eosinophilic enteritis. The number of hookworms was negatively correlated with intestinal villous length and number of leukocytes in the intestine. Pups with hookworm peritoneal penetration had nematodes with little or no blood in the hookworm intestine, suggesting that lack of food for the nematode could be associated with peritoneal penetration. Findings suggest that the initial burden of larval infection, the level of the host tissue response, or a combination determine the number of nematodes in the intestine, the severity of hookworm tissue damage, and pup mortality.
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Affiliation(s)
- M Seguel
- 1 Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA
| | - F Muñoz
- 2 Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - M J Navarrete
- 2 Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - E Paredes
- 2 Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - E Howerth
- 1 Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA
| | - N Gottdenker
- 1 Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA
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Loukas A, Hotez PJ, Diemert D, Yazdanbakhsh M, McCarthy JS, Correa-Oliveira R, Croese J, Bethony JM. Hookworm infection. Nat Rev Dis Primers 2016; 2:16088. [PMID: 27929101 DOI: 10.1038/nrdp.2016.88] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hookworms are soil-transmitted nematode parasites that can reside for many years in the small intestine of their human hosts; Necator americanus is the predominant infecting species. Adult worms feed on the blood of a host and can cause iron deficiency anaemia, especially in high-risk populations (children and women of childbearing age). Almost 500 million people in developing tropical countries are infected, and simulation models estimate that hookworm infection is responsible for >4 million disability-adjusted life years lost annually. Humans mount an immune response to hookworms, but it is mostly unsuccessful at removing adult worms from the bowel. Accordingly, the host switches to an immune-tolerant state that enables hookworms to reside in the gut for many years. Although anthelmintic drugs are available and widely used, their efficacy varies and the drugs do not prevent reinfection. Thus, other control strategies aimed at improving water quality, sanitation and hygiene are needed. In addition, efforts are underway to develop a human hookworm vaccine through public-private partnerships. However, hookworms could also be a resource; as hookworms have the capability to regulate the host's inflammation, researchers are experimentally infecting patients to treat some inflammatory diseases as an approach to discover new anti-inflammatory molecules. This area of endeavour might well yield new biotherapeutics for autoimmune and allergic diseases.
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Affiliation(s)
- Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, Building E4, James Cook University, McGregor Rd, Smithfield, Cairns, Queensland 4878, Australia
| | - Peter J Hotez
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College Of Medicine, Houston, Texas, USA.,Sabin Vaccine Institute, Houston, Texas, USA.,Texas Children's Hospital Center for Vaccine Development, Houston, Texas, USA
| | - David Diemert
- Department of Microbiology, Tropical Medicine and Immunology, George Washington University, Washington DC, USA.,Sabin Vaccine Institute, Washington DC, USA
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - James S McCarthy
- Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, Queensland, Australia.,University of Queensland, Brisbane, Queensland, Australia
| | | | - John Croese
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, Building E4, James Cook University, McGregor Rd, Smithfield, Cairns, Queensland 4878, Australia.,Department of Gastroenterology, Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Jeffrey M Bethony
- Department of Microbiology, Tropical Medicine and Immunology, George Washington University, Washington DC, USA
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Wei J, Damania A, Gao X, Liu Z, Mejia R, Mitreva M, Strych U, Bottazzi ME, Hotez PJ, Zhan B. The hookworm Ancylostoma ceylanicum intestinal transcriptome provides a platform for selecting drug and vaccine candidates. Parasit Vectors 2016; 9:518. [PMID: 27677574 PMCID: PMC5039805 DOI: 10.1186/s13071-016-1795-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/12/2016] [Indexed: 12/02/2022] Open
Abstract
Background The intestine of hookworms contains enzymes and proteins involved in the blood-feeding process of the parasite and is therefore a promising source of possible vaccine antigens. One such antigen, the hemoglobin-digesting intestinal aspartic protease known as Na-APR-1 from the human hookworm Necator americanus, is currently a lead candidate antigen in clinical trials, as is Na-GST-1 a heme-detoxifying glutathione S-transferase. Methods In order to discover additional hookworm vaccine antigens, messenger RNA was obtained from the intestine of male hookworms, Ancylostoma ceylanicum, maintained in hamsters. RNA-seq was performed using Illumina high-throughput sequencing technology. The genes expressed in the hookworm intestine were compared with those expressed in the whole worm and those genes overexpressed in the parasite intestine transcriptome were further analyzed. Results Among the lead transcripts identified were genes encoding for proteolytic enzymes including an A. ceylanicum APR-1, but the most common proteases were cysteine-, serine-, and metallo-proteases. Also in abundance were specific transporters of key breakdown metabolites, including amino acids, glucose, lipids, ions and water; detoxifying and heme-binding glutathione S-transferases; a family of cysteine-rich/antigen 5/pathogenesis-related 1 proteins (CAP) previously found in high abundance in parasitic nematodes; C-type lectins; and heat shock proteins. These candidates will be ranked for downstream antigen target selection based on key criteria including abundance, uniqueness in the parasite versus the vertebrate host, as well as solubility and yield of expression. Conclusion The intestinal transcriptome of A. ceylanicum provides useful information for the identification of proteins involved in the blood-feeding process, representing a first step towards a reverse vaccinology approach to a human hookworm vaccine. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1795-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Junfei Wei
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ashish Damania
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xin Gao
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, 63108, USA
| | - Zhuyun Liu
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Rojelio Mejia
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Makedonka Mitreva
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, 63108, USA.,Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63108, USA
| | - Ulrich Strych
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Maria Elena Bottazzi
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Biology, Baylor University, Waco, TX, 76706, USA
| | - Peter J Hotez
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Biology, Baylor University, Waco, TX, 76706, USA
| | - Bin Zhan
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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22
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East ML, Otto E, Helms J, Thierer D, Cable J, Hofer H. Does lactation lead to resource allocation trade-offs in the spotted hyaena? Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1897-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Marcus AD, Higgins DP, Gray R. Health assessment of free-ranging endangered Australian sea lion (Neophoca cinerea) pups: effect of haematophagous parasites on haematological parameters. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:132-43. [PMID: 25724096 DOI: 10.1016/j.cbpa.2015.02.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 02/07/2023]
Abstract
Evaluation of the health status of free-ranging populations is important for understanding the impact of disease on individuals and on population demography and viability. In this study, haematological reference intervals were developed for free-ranging endangered Australian sea lion (Neophoca cinerea) pups within the context of endemic hookworm (Uncinaria sanguinis) infection and the effects of pathogen, host, and environment factors on the variability of haematological parameters were investigated. Uncinaria sanguinis was identified as an important agent of disease, with infection causing regenerative anaemia, hypoproteinaemia, and a predominantly lymphocytic-eosinophilic systemic inflammatory response. Conversely, the effects of sucking lice (Antarctophthirus microchir) were less apparent and infestation in pups appears unlikely to cause clinical impact. Overall, the effects of U. sanguinis, A. microchir, host factors (standard length, body condition, pup sex, moult status, and presence of lesions), and environment factors (capture-type and year of sampling) accounted for 26-65% of the total variance observed in haematological parameters. Importantly, this study demonstrated that anaemia in neonatal Australian sea lion pups is not solely a benign physiological response to host-environment changes, but largely reflects a significant pathological process. This impact of hookworm infection on pup health has potential implications for the development of foraging and diving behaviour, which would subsequently influence the independent survival of juveniles following weaning. The haematological reference intervals developed in this study can facilitate long-term health surveillance, which is critical for the early recognition of changes in disease impact and to inform conservation management.
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Affiliation(s)
- Alan D Marcus
- Faculty of Veterinary Science, The University of Sydney, McMaster Building B14, Camperdown, New South Wales 2006, Australia
| | - Damien P Higgins
- Faculty of Veterinary Science, The University of Sydney, McMaster Building B14, Camperdown, New South Wales 2006, Australia
| | - Rachael Gray
- Faculty of Veterinary Science, The University of Sydney, McMaster Building B14, Camperdown, New South Wales 2006, Australia.
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Evaluation of biochemical, hematological and parasitological parameters of protein-deficient hamsters infected with Ancylostoma ceylanicum. PLoS Negl Trop Dis 2014; 8:e3184. [PMID: 25254370 PMCID: PMC4177863 DOI: 10.1371/journal.pntd.0003184] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 08/12/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hookworms infect millions of people worldwide and can cause severe clinical symptoms in their hosts. Prospective cohort studies in Brazil show high rates of hookworm reinfection in malnourished children compared to well-nourished children, despite previous treatment. Additionally, soil-transmitted helminth (STH) infections can worsen the nutritional status of affected populations. Therefore, this study aims to clarify the effects of host malnutrition during Ancylostoma ceylanicum infection and how this infection affects host physiological parameters using a hamster model. METHODOLOGY/PRINCIPAL FINDINGS Hamsters were divided into four experimental groups: normal diet or low-protein diet (also referred to as "malnourished") and A. ceylanicum infection or no infection. More severe pathogenesis was observed in the infected malnourished group, as demonstrated by significant decreases in the hemoglobin concentration, erythrocyte number and packed-cell volume compared to the non-infected malnourished group. Greater numbers of adult parasites and eggs were observed in the malnourished group compared to the control group; however, the oviposition rate was lower in the malnourished group. In general, greater values of total lipids were observed in malnourished animals compared to control animals, including lipids excreted in the stool. CONCLUSIONS In this work, we have demonstrated that animals fed an isocaloric low-protein diet presented more severe pathogenesis when infected with A. ceylanicum. The increased lipid concentration in the liver and blood is related to the conversion of the excess carbohydrate into fatty acids that increase the concentration of triglycerides in general. Triglycerides were excreted in the feces, indicating that infection associated with malnutrition caused a greater loss of these molecules for this group of animals and confirming the hypothesis that both nutrition and infection are responsible for the malabsorption syndrome. Taken together, the results found in this work confirm the hypothesis that the nutritional condition of the host greatly influences the course of the infection.
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25
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Hawdon JM. Controlling Soil-Transmitted Helminths: Time to Think Inside the Box? J Parasitol 2014; 100:166-88. [DOI: 10.1645/13-412.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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26
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Evaluation of parasitological and immunological aspects of acute infection by Ancylostoma caninum and Ancylostoma braziliense in mixed-breed dogs. Parasitol Res 2013; 112:2151-7. [PMID: 23494155 DOI: 10.1007/s00436-013-3370-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 02/26/2013] [Indexed: 10/27/2022]
Abstract
This study compared the course of infection by Ancylostoma caninum and Ancylostoma braziliense in mixed-breed dogs infected with L3 larvae. Dogs infected with A. caninum eliminated more eggs than did those infected with A. braziliense. A total of 38 % of A. caninum and 44 % of A. braziliense larvae were recovered as adult worms. There were no marked clinical abnormalities in dogs with either infection. A. caninum was associated with anemia and an increased number of circulating neutrophils, whereas infection with A. braziliense led to a decrease in the number of leukocytes. The humoral response against excreted and secreted antigens from adult worms was more sensitive and specific than the response induced with the crude antigen. No immune response was observed for either crude or excreted-secreted (ES) antigens from larvae of either species. A nonspecific response against the crude antigen of A. braziliense was found at 0 and 7 days postinfection and maintained throughout the infection period. However, antibody titers against ES antigens were elevated in A. caninum infection at patency and death, showing that this antigen has a higher specificity. The immune response elicited by infection with A. braziliense in dogs has not been described previously. No significant differences were observed in the infection processes of the two Ancylostoma species, except for the higher number of eggs eliminated from dogs infected with A. caninum, which may indicate a better evolutionary adaptation of the parasite to its host in comparison with A. braziliense.
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Prednisolone and cyclosporine A: Effects on an experimental model of ancylostomiasis. Exp Parasitol 2013; 133:80-8. [PMID: 23142084 DOI: 10.1016/j.exppara.2012.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 09/20/2012] [Accepted: 10/19/2012] [Indexed: 10/27/2022]
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Periago MV, Bethony JM. Hookworm virulence factors: making the most of the host. Microbes Infect 2012; 14:1451-64. [DOI: 10.1016/j.micinf.2012.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/16/2012] [Accepted: 09/03/2012] [Indexed: 11/25/2022]
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Ricci ND, Fiúza JA, Bueno LL, Cançado GGL, Gazzinelli-Guimarães PH, Martins VG, Matoso LF, de Miranda RRC, Geiger SM, Correa-Oliveira R, Gazzinelli A, Bartholomeu DC, Fujiwara RT. Induction of CD4(+)CD25(+)FOXP3(+) regulatory T cells during human hookworm infection modulates antigen-mediated lymphocyte proliferation. PLoS Negl Trop Dis 2011; 5:e1383. [PMID: 22087344 PMCID: PMC3210756 DOI: 10.1371/journal.pntd.0001383] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 09/18/2011] [Indexed: 02/07/2023] Open
Abstract
Hookworm infection is considered one of the most important poverty-promoting neglected tropical diseases, infecting 576 to 740 million people worldwide, especially in the tropics and subtropics. These blood-feeding nematodes have a remarkable ability to downmodulate the host immune response, protecting themselves from elimination and minimizing severe host pathology. While several mechanisms may be involved in the immunomodulation by parasitic infection, experimental evidences have pointed toward the possible involvement of regulatory T cells (Tregs) in downregulating effector T-cell responses upon chronic infection. However, the role of Tregs cells in human hookworm infection is still poorly understood and has not been addressed yet. In the current study we observed an augmentation of circulating CD4(+)CD25(+)FOXP3(+) regulatory T cells in hookworm-infected individuals compared with healthy non-infected donors. We have also demonstrated that infected individuals present higher levels of circulating Treg cells expressing CTLA-4, GITR, IL-10, TGF-β and IL-17. Moreover, we showed that hookworm crude antigen stimulation reduces the number of CD4(+)CD25(+)FOXP3(+) T regulatory cells co-expressing IL-17 in infected individuals. Finally, PBMCs from infected individuals pulsed with excreted/secreted products or hookworm crude antigens presented an impaired cellular proliferation, which was partially augmented by the depletion of Treg cells. Our results suggest that Treg cells may play an important role in hookworm-induced immunosuppression, contributing to the longevity of hookworm survival in infected people.
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Affiliation(s)
- Natasha Delaqua Ricci
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Brazil
| | - Jacqueline Araújo Fiúza
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Laboratory of Cellular and Molecular Immunology, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Lilian Lacerda Bueno
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Guilherme Grossi Lopes Cançado
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Clinical Hospital, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Pedro Henrique Gazzinelli-Guimarães
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Brazil
| | - Virgillio Gandra Martins
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Brazil
| | - Leonardo Ferreira Matoso
- Laboratory of Cellular and Molecular Immunology, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | | | - Stefan Michael Geiger
- Laboratory of Cellular and Molecular Immunology, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Correa-Oliveira
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Brazil
- Laboratory of Cellular and Molecular Immunology, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Andréa Gazzinelli
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Brazil
- School of Nursing, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Ricardo Toshio Fujiwara
- Department of Parasitology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Brazil
- Laboratory of Cellular and Molecular Immunology, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Schneider B, Jariwala AR, Periago MV, Gazzinelli MF, Bose SN, Hotez PJ, Diemert DJ, Bethony JM. A history of hookworm vaccine development. HUMAN VACCINES 2011; 7:1234-44. [PMID: 22064562 DOI: 10.4161/hv.7.11.18443] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The human hookworms Necator americanus and Ancylostoma duodenale remain among the most common infections of humans in areas of rural poverty in the developing regions of the world, with an estimated 1 billion people infected with one or more of these parasites. Herein, we review the nearly 100 years of research, development, animal testing, and fieldwork that have led to our current progress in recombinant hookworm vaccines. We begin with the identification of hookworm at the start of the 20th century in Southern US, then discuss the progress in developed countries to eliminate human hookworm infection, and then the industrial development and field use in the 1970s a canine hookworm vaccine(Ancylostoma caninum), and finally our progress to date in the development and clinical testing of an array of recombinant antigens to prevent human hookworm disease from N. americanus infection. Special attention is given to the challenges faced in the development of a vaccine against a blood-feeding nematode, including the epidemiology of infection (high prevalence of infection), pathogenesis (chronic infection that increases with the age of the host), and a robust immune response that fails to confer the protection in the host and a concomitant absence of correlates of protection by a successful vaccine could be developed and tested. Finally, we provide the optimal and acceptable profiles of a human hookworm vaccine, including the proposed indication, target population, and route of administration, as developed by the Human Hookworm Vaccine Initiative, the only group currently working on vaccines targeting this parasite.
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Affiliation(s)
- Brent Schneider
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University Medical Center; Washington, DC USA
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31
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Cançado GGL, Fiuza JA, de Paiva NCN, Lemos LDCD, Ricci ND, Gazzinelli-Guimarães PH, Martins VG, Bartholomeu DC, Negrão-Corrêa DA, Carneiro CM, Fujiwara RT. Hookworm products ameliorate dextran sodium sulfate-induced colitis in BALB/c mice. Inflamm Bowel Dis 2011; 17:2275-86. [PMID: 21290484 DOI: 10.1002/ibd.21629] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/08/2010] [Indexed: 12/26/2022]
Abstract
BACKGROUND Several lines of evidence have shown that helminthiasis can significantly reduce disease severity in animal models of intestinal inflammation, airway inflammation/hyperreactivity, diabetes, and multiple sclerosis. Identification and characterization of helminth-derived immunomodulatory molecules that contribute to anticolitis effects could lead to new therapeutic approaches in inflammatory bowel diseases (IBDs) without the need for helminth infection. We evaluated the therapeutic potential of adult human hookworm, Ancylostoma ceylanicum, crude (Aw) and excreted/secreted (ES) products on dextran sulfate sodium (DSS)-induced colitis in BALB/c mice. METHODS Colitis was induced by 5% DSS oral administration for 7 days. Clinical disease severity was monitored daily during concomitant intraperitoneal treatment with helminth-derived products. Additionally, several pathways of immunological modulation induced by A. ceylanicum products (MPO, EPO, Th1, Th2, and Th17 cytokine responses) in the inflamed intestinal microenvironment were assessed. Finally, the histopathological profile of the colon was characterized. RESULTS Hookworm products are able to modulate the potent proinflammatory response induced by DSS, mainly through the downregulation of Th1 and Th17 cytokines. These proteins also reduce clinical and colonic microscopic inflammation scores as well as EPO and MPO activity. CONCLUSIONS Ancylostoma ceylanicum Aw and ES mediators have an important therapeutic potential in experimental colitis in mice, which may provide a more socially acceptable form of therapy for patients with IBDs as opposed to using living worms. Our results support the urgency of further isolation and recombinant expression of active hookworm products responsible for the beneficial effects on colitis.
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Bethony JM, Cole RN, Guo X, Kamhawi S, Lightowlers MW, Loukas A, Petri W, Reed S, Valenzuela JG, Hotez PJ. Vaccines to combat the neglected tropical diseases. Immunol Rev 2011; 239:237-70. [PMID: 21198676 DOI: 10.1111/j.1600-065x.2010.00976.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The neglected tropical diseases (NTDs) represent a group of parasitic and related infectious diseases such as amebiasis, Chagas disease, cysticercosis, echinococcosis, hookworm, leishmaniasis, and schistosomiasis. Together, these conditions are considered the most common infections in low- and middle-income countries, where they produce a level of global disability and human suffering equivalent to better known conditions such as human immunodeficiency virus/acquired immunodeficiency syndrome and malaria. Despite their global public health importance, progress on developing vaccines for NTD pathogens has lagged because of some key technical hurdles and the fact that these infections occur almost exclusively in the world's poorest people living below the World Bank poverty line. In the absence of financial incentives for new products, the multinational pharmaceutical companies have not embarked on substantive research and development programs for the neglected tropical disease vaccines. Here, we review the current status of scientific and technical progress in the development of new neglected tropical disease vaccines, highlighting the successes that have been achieved (cysticercosis and echinococcosis) and identifying the challenges and opportunities for development of new vaccines for NTDs. Also highlighted are the contributions being made by non-profit product development partnerships that are working to overcome some of the economic challenges in vaccine manufacture, clinical testing, and global access.
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Affiliation(s)
- Jeffrey M Bethony
- Microbiology, Immunology, and Tropical Medicine, George Washington University Medical Center, Washington, DC 20037, USA.
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Excretory-secretory products from hookworm l(3) and adult worms suppress proinflammatory cytokines in infected individuals. J Parasitol Res 2011; 2011:512154. [PMID: 21772981 PMCID: PMC3135091 DOI: 10.1155/2011/512154] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 03/18/2011] [Accepted: 03/29/2011] [Indexed: 11/17/2022] Open
Abstract
We compared the effects of larval and adult worm excretory-secretory (ES) products from hookworm on the proliferative responses and cytokine secretion in peripheral blood mononuclear cells (PBMCs) from hookwormpatients and egg-negative, nonendemic controls. When compared with negative controls, mitogen-stimulated PBMC from hookworm-infected individuals showed a significantly reduced proliferative response when adult worm ES antigen was added to the cultures. Furthermore, in hookworm-infected individuals a significant downmodulation of inflammatory interleukin (IL)-6 and tumor necrosis factor (TNF)-α secretion resulted when PBMCs were stimulated with mitogen in combination with larval or adult worm ES. Both, interferon (IFN)-γ and IL-10 secretion were significantly lower in stimulated PBMC from infected individuals; however the IFN-γ/IL-10 ratio was much lower in hookworm-infected patients. Comparable effects, although at lower concentrations, were achieved when PBMCs from both groups were incubated with living hookworm third-stage larvae. We suggest that hookworm ES products downmodulate proliferative responses and inflammation during the chronic phase of the disease and facilitate early larval survival or adult worm persistence in the gut.
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The mucosal response of hamsters to a low-intensity superimposed secondary infection with the hookworm Ancylostoma ceylanicum. J Helminthol 2010; 85:56-65. [DOI: 10.1017/s0022149x10000283] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractAn experiment was conducted to assess the mucosal response to low-dose superimposed challenge with Ancylostoma ceylanicum. Hamsters were assigned to five treatment groups (1–5 respectively): naïve controls; primary immunizing infection controls; challenge controls; immunized, anthelmintic–treated, challenged group; immunized, superimposed challenge group. Group 4 hamsters were resistant to challenge, whereas most of the challenge inoculum larvae established in Group 5. Villus height and crypt depth measurements were initially markedly divergent between these two groups but over time post-challenge (pc) values for both parameters drew nearer and by day 31 pc they were indistinguishable. The greatest change was experienced by Group 4 which showed increasing inflammation and gut pathology during the challenge infection. Mitotic activity in crypts and mast cell counts in the mucosa were highest in Group 5 on day 10 pc, but there was little to distinguish between Groups 4 and 5 by day 31 pc. Goblet cell, eosinophil and Paneth cell counts were very similar throughout in both groups but, in the case of Paneth cells, they were consistent with a possible role in protective immunity to challenge. Some adult worms survived throughout the period of intense inflammation, emphasizing their tremendous resilience and resistance to mucosal host protective responses.
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Alkazmi L, Behnke JM. The mucosal response to secondary infection with Ancylostoma ceylanicum in hamsters immunized by abbreviated primary infection. Parasite Immunol 2010; 32:47-56. [PMID: 20042007 DOI: 10.1111/j.1365-3024.2009.01158.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We assessed the mucosal response of previously infected hamsters to low-dose challenge with the hookworm, Ancylostoma ceylanicum. Hamsters were assigned to five treatment groups (Groups 1-5, respectively): naïve, controls; uninterrupted primary infection from day 0; infected, but treated with anthelmintic on day 35 p.i.; challenge control group given only the second infection on day 63; infected initially, cleared of worms and then challenged. Animals were culled on days 73 and 94 (10 and 31 days after challenge), but additional animals were culled from Group 5 on days 80 and 87. The results showed that villus height declined markedly and progressively over time after challenge in Group 5, whilst depth of the Crypts of Lieberkühn and number of mitotic figures in the crypts increased. Mucosal mast cell numbers were only marginally higher than those in naïve controls and not as high as those in mice with uninterrupted infections. Goblet cell counts showed a major increase, as did eosinophils in relation to naïve controls. Paneth cells were also elevated, but did not change over the course of the experiment. The results also drew attention to the tremendous resilience of hookworms, some adult worms surviving throughout, despite highly inflamed intestines.
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Affiliation(s)
- L Alkazmi
- School of Biology, University of Nottingham, Nottingham, UK
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Fujiwara RT, Cançado GGL, Freitas PA, Santiago HC, Massara CL, Carvalho ODS, Corrêa-Oliveira R, Geiger SM, Bethony J. Necator americanus infection: a possible cause of altered dendritic cell differentiation and eosinophil profile in chronically infected individuals. PLoS Negl Trop Dis 2009; 3:e399. [PMID: 19308259 PMCID: PMC2654967 DOI: 10.1371/journal.pntd.0000399] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 02/26/2009] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Hookworms survive for several years (5 to 7 years) in the host lumen, inducing a robust but largely ineffective immune response. Among the most striking aspects of the immune response to hookworm (as with many other helminths) is the ablation of parasite-specific T cell proliferative response (hyporesponsiveness). While the role of the adaptive immune response in human helminth infection has been well investigated, the role of the innate immune responses (e.g., dendritic cells and eosinophils) has received less attention and remains to be clearly elucidated. METHODOLOGY/PRINCIPAL FINDINGS We report on the differentiation/maturation of host dendritic cells in vitro and the eosinophil activation/function associated with human hookworm infection. Mature DCs (mDCs) from Necator americanus (Necator)-infected individuals showed an impaired differentiation process compared to the mDCs of non-infected individuals, as evidenced by the differential expression of CD11c and CD14. These same hookworm-infected individuals also presented significantly down-regulated expression of CD86, CD1a, HLA-ABC, and HLA-DR. The lower expression of co-stimulatory and antigen presentation molecules by hookworm-infected-derived mDCs was further evidenced by their reduced ability to induce cell proliferation. We also showed that this alternative DC differentiation is partially induced by excreted-secreted hookworm products. Conversely, eosinophils from the same individuals showed a highly activated status, with an upregulation of major cell surface markers. Antigen-pulsed eosinophils from N. americanus-infected individuals induced significant cell proliferation of autologous PBMCs, when compared to non-infected individuals. CONCLUSION Chronic N. americanus infection alters the host's innate immune response, resulting in a possible modulation of the maturation process of DCs, a functional change that may diminish their ability for antigen presentation and thus contribute to the ablation of the parasite-specific T cell proliferative response. Interestingly, a concomitant upregulation of the major cell surface markers of eosinophils was observed in hookworm-infected individuals, indicative of antigen-specific immune responses, especially antigen presentation. We showed that in addition to the postulated role of the eosinophils as effector cells against helminth infection, activated cells may also be recruited to sites of inflammation and contribute to the immune response acting as antigen presenting cells.
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Affiliation(s)
- Ricardo T. Fujiwara
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Guilherme G. L. Cançado
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Paula A. Freitas
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Helton C. Santiago
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
| | - Cristiano Lara Massara
- Laboratory of Helminthology and Medical Malacology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Omar dos Santos Carvalho
- Laboratory of Helminthology and Medical Malacology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Corrêa-Oliveira
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Stefan M. Geiger
- Laboratory of Cellular and Molecular Immunology, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Minas Gerais, Brazil
| | - Jeffrey Bethony
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
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BUNGIRO RD, SUN T, HARRISON LM, SHOEMAKER CB, CAPPELLO M. Mucosal antibody responses in experimental hookworm infection. Parasite Immunol 2008; 30:293-303. [DOI: 10.1111/j.1365-3024.2008.01023.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abstract
Hookworm infection is a major cause of anemia and malnutrition in resource-poor countries. Human and animal studies suggest that infection with these intestinal nematodes is associated with impaired cellular immunity, characterized by reduced lymphocyte proliferation in response to both parasite and heterologous antigens. We report here data from studies aimed at defining mechanisms through which hookworms modulate the host cellular immune response. Splenocytes and mesenteric lymph node (MLN) cells from hamsters infected with Ancylostoma ceylanicum showed minimal proliferation in response to mitogen at days 20 and 30 postinfection (p.i.), with partial recovery noted at day 70 p.i. The proliferative capacity of enriched splenocyte T-cell preparations from infected animals following stimulation with hookworm antigens was partially restored in the presence of antigen-presenting cells from uninfected hamsters. Analysis by fluorescence-activated cell sorting revealed that hookworm infection is associated with reduced percentages of both CD4(+) and surface immunoglobulin G-positive lymphocytes in the spleen and MLN cells. Splenocytes from infected hamsters also secreted more nitric oxide (NO) in culture than did those from naïve animals. Inhibition of NO secretion was associated with partial restoration of the proliferative capacity of splenocytes from infected animals in response to concanavalin A, suggesting a role for NO in mediating this effect. Together, these data demonstrate that hookworm infection is associated with impaired function of antigen-presenting cells and depletion of important lymphocyte subpopulations and also suggests a role for NO in parasite-induced immunosuppression.
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Xiao S, Zhan B, Xue J, Goud GN, Loukas A, Liu Y, Williamson A, Liu S, Deumic V, Hotez P. The evaluation of recombinant hookworm antigens as vaccines in hamsters (Mesocricetus auratus) challenged with human hookworm, Necator americanus. Exp Parasitol 2007; 118:32-40. [PMID: 17645877 DOI: 10.1016/j.exppara.2007.05.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 05/25/2007] [Accepted: 05/29/2007] [Indexed: 11/23/2022]
Abstract
We have previously reported the successful adaptation of human hookworm Necator americanus in the golden hamster, Mesocricetus auratus. This animal model was used to test a battery of hookworm (N. americanus and Ancylostoma caninum) recombinant antigens as potential vaccine antigens. Hamsters immunized a leading vaccine candidate N. americanus-Ancylostoma secreted protein 2 (Na-ASP-2) and challenged with N. americanus infective larvae (L3), resulted in 30-46.2% worm reduction over the course of three vaccine trials, relative to adjuvant controls. In addition, significant reduction of worm burdens was also observed in the hamsters immunized with adult hookworm antigens A. caninum aspartic protease 1 (Ac-APR-1); A. caninum-glutathione-S transferase 1 (Ac-GST-1) and Necator cysteine proteases 2 (Na-CP-2) (44.4%, 50.6%, and 29.3%, respectively). Our data on the worm burden reductions afforded by these hookworm antigens approximate the level of protection reported previously from dogs challenged with A. caninum L3, and provide additional evidence to support these hookworm antigens as vaccine candidates for human hookworm infection. The hamster model of N. americanus provides useful information for the selection of antigens to be tested in downstream vaccine development.
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Affiliation(s)
- Shuhua Xiao
- Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China
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