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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 2024; 42:S25-S41. [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] [MESH Headings] [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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2
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Drurey C, Maizels RM. Helminth extracellular vesicles: Interactions with the host immune system. Mol Immunol 2021; 137:124-133. [PMID: 34246032 PMCID: PMC8636279 DOI: 10.1016/j.molimm.2021.06.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/14/2021] [Accepted: 06/23/2021] [Indexed: 12/21/2022]
Abstract
As long-lived parasites, helminths depend upon immunomodulation of their hosts for survival. The release of excretory-secretory (ES) products, including proteins, lipids and RNAs is how successful host manipulation is achieved. It has recently been discovered that the ES products of helminths contain extracellular vesicles (EVs), with every species investigated found to secrete these lipid-bound structures. EVs are perfect for packaging and delivering immune modulators to target cell types. This review outlines the research carried out on helminth EVs and their constituents thus far, as well as their interaction with components of the mammalian immune system. We discuss how targeting EVs will aid treatment of helminth infection and consider how EVs and their immunomodulatory cargo could be used as therapeutics as we progress through this exciting era.
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Affiliation(s)
- Claire Drurey
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Rick M Maizels
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, UK.
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3
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Saracino MP, Vila CC, Baldi PC, González Maglio DH. Searching for the one(s): Using Probiotics as Anthelmintic Treatments. Front Pharmacol 2021; 12:714198. [PMID: 34434110 PMCID: PMC8381770 DOI: 10.3389/fphar.2021.714198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/22/2021] [Indexed: 12/29/2022] Open
Abstract
Helminths are a major health concern as over one billion people are infected worldwide and, despite the multiple efforts made, there is still no effective human vaccine against them. The most important drugs used nowadays to control helminth infections belong to the benzimidazoles, imidazothiazoles (levamisole) and macrocyclic lactones (avermectins and milbemycins) families. However, in the last 20 years, many publications have revealed increasing anthelmintic resistance in livestock which is both an economical and a potential health problem, even though very few have reported similar findings in human populations. To deal with this worrying limitation of anthelmintic drugs, alternative treatments based on plant extracts or probiotics have been developed. Probiotics are defined by the Food and Agriculture Organization as live microorganisms, which, when consumed in adequate amounts, confer a health benefit to the host. It has been proven that probiotic microbes have the ability to exert an immunomodulatory effect both at the mucosa and the systemic level. The immune response against gastrointestinal helminths is characterized as a type 2 response, with high IgE levels, increased numbers and/or activity of Th2 cells, type 2 innate lymphoid cells, eosinophils, basophils, mast cells, and alternatively activated macrophages. The oral administration of probiotics may contribute to controlling gastrointestinal helminth infections since it has been demonstrated that these microorganisms stimulate dendritic cells to elicit a type 2 or regulatory immune response, among other effects on the host immune system. Here we review the current knowledge about the use of probiotic bacteria as anthelmintic therapy or as a complement to traditional anthelmintic treatments. Considering all research papers reviewed, we may conclude that the effect generated by probiotics on helminth infection depends not only on the parasite species, their stage and localization but also on the administration scheme.
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Affiliation(s)
- Maria Priscila Saracino
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cecilia Celeste Vila
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Pablo César Baldi
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Daniel Horacio González Maglio
- Cátedra de Inmunología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
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4
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Hayon J, Weatherhead J, Hotez PJ, Bottazzi ME, Zhan B. Advances in vaccine development for human trichuriasis. Parasitology 2021; 148:1-12. [PMID: 33757603 DOI: 10.1017/s0031182021000500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Trichuriasis known as whipworm infection caused by Trichuris trichiura, is a highly prevalent soil-transmitted helminthiasis in low- and middle-income countries located in tropical and subtropical areas and affecting approximately 360 million people. Children typically harbour the largest burden of T. trichiura and they are usually co-infected with other soil-transmitted helminth (STH), including Ascaris lumbricoides and hookworm. The consequences of trichuriasis, such as malnutrition and physical and cognitive growth restriction, lead to a massive health burden in endemic regions. Despite the implementation of mass drug administration of anthelminthic treatment to school-age children, T. trichiura infection remains challenging to control due to the low efficacy of current drugs as well as high rates of post-treatment re-infection. Thus, the development of a vaccine that would induce protective immunity and reduce infection rate or community faecal egg output is essential. Hurdles for human whipworm vaccine development include the lack of suitable vaccine antigen targets and animal models for human T. trichiura infection. Instead, rodent whipworm T. muris infected mouse models serve as a major surrogate for testing immunogenicity and efficacy of vaccine candidates. In this review, we summarize recent advances in animal models for T. trichiura antigen discovery and testing of vaccine candidates, while providing an overall view of the current status of T. trichiura vaccine development.
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Affiliation(s)
- Jesica Hayon
- Department of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, USA
| | - Jill Weatherhead
- Department of Medicine, Section of Infectious Diseases, Baylor College of Medicine, Houston, TX, USA
- Department of Pediatrics, Section of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Peter J Hotez
- Department of Pediatrics, Section of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX77030, USA
| | - Maria Elena Bottazzi
- Department of Pediatrics, Section of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX77030, USA
| | - Bin Zhan
- Department of Pediatrics, Section of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX77030, USA
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5
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Keitel WA, Potter GE, Diemert D, Bethony J, El Sahly HM, Kennedy JK, Patel SM, Plieskatt JL, Jones W, Deye G, Bottazzi ME, Hotez PJ, Atmar RL. A phase 1 study of the safety, reactogenicity, and immunogenicity of a Schistosoma mansoni vaccine with or without glucopyranosyl lipid A aqueous formulation (GLA-AF) in healthy adults from a non-endemic area. Vaccine 2019; 37:6500-6509. [PMID: 31515141 DOI: 10.1016/j.vaccine.2019.08.075] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND Schistosomiasis caused by Schistosoma mansoni (Sm) is a chronic, debilitating and potentially deadly neglected tropical disease. The licensure of a vaccine to prevent schistosomiasis would represent a major breakthrough in public health. METHODS The safety and immunogenicity of a candidate Sm vaccine were assessed in this phase I, double-blind, dose-escalation trial. Seventy-two healthy Sm-naïve 18-50 year olds were randomized to receive 3 doses ∼ 8 weeks apart of saline placebo, or 10 µg, 30 µg, or 100 µg of recombinant Sm-Tetraspanin-2 vaccine formulated on aluminum hydroxide adjuvant (Sm-TSP-2/Al) with or without 5 µg of glucopyranosyl lipid A aqueous formulation (GLA-AF). Clinical and serologic responses were assessed for 1 year after dose 3. RESULTS Vaccines were safe and well-tolerated. The most common reactions were injection site tenderness and pain, and headache and fatigue. Tenderness and pain were more frequent in groups receiving vaccine with GLA-AF than placebo (p = 0.0036 and p = 0.0014, respectively). Injection site reactions among those given Sm-TSP-2/Al with GLA-AF lasted 1.22 and 1.33 days longer than those receiving Sm-TSP-2/Al without GLA-AF or placebo (p < 0.001 for both). Dose- and adjuvant-related increases in serum IgG against Sm-TSP-2 were observed. Peak IgG levels occurred 14 days after dose 3. Seroresponse frequencies were low among recipients of Sm-TSP-2/Al without GLA-AF, but higher among subjects receiving 30 µg or 100 µg of Sm-TSP-2/Al with GLA-AF. More seroresponses were observed among those given 30 µg or 100 µg of Sm-TSP-2/Al with GLA-AF compared to placebo (p = 0.023 and p < 0.001, respectively). Seroresponse frequencies were 0%, 30%, 50%, and 89%, respectively, among those given placebo, or 10 µg, 30 µg or 100 µg of Sm-TSP-2/Al with GLA-AF, suggesting a dose-response relationship for Sm-TSP-2/Al with GLA-AF (p = 0.0001). CONCLUSIONS Sm-TSP-2/Al with or without GLA-AF was safe and well tolerated in a Sm-naïve population. A vaccine like the one under development may represent our best hope to eliminating this neglected tropical disease.
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Affiliation(s)
- W A Keitel
- Departments of Molecular Virology & Microbiology and Medicine, Baylor College of Medicine, Houston, TX, United States.
| | | | - D Diemert
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
| | - J Bethony
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
| | - H M El Sahly
- Departments of Molecular Virology & Microbiology and Medicine, Baylor College of Medicine, Houston, TX, United States
| | | | - S M Patel
- Departments of Molecular Virology & Microbiology and Medicine, Baylor College of Medicine, Houston, TX, United States
| | - J L Plieskatt
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, United States
| | - W Jones
- Division of Microbiology and Infectious Diseases (DMID), National Institutes of Allergy and Infectious. Diseases (NIAID), National Institutes of Health (NIH), United States
| | - G Deye
- Division of Microbiology and Infectious Diseases (DMID), National Institutes of Allergy and Infectious. Diseases (NIAID), National Institutes of Health (NIH), United States
| | - M E Bottazzi
- Departments of Molecular Virology & Microbiology and Medicine, Baylor College of Medicine, Houston, TX, United States; Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - P J Hotez
- Departments of Molecular Virology & Microbiology and Medicine, Baylor College of Medicine, Houston, TX, United States; Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - R L Atmar
- Departments of Molecular Virology & Microbiology and Medicine, Baylor College of Medicine, Houston, TX, United States
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Claus PE, Ceuppens AS, Cool M, Alliet G. Ascaris lumbricoides: challenges in diagnosis, treatment and prevention strategies in a European refugee camp. Acta Clin Belg 2018; 73:431-434. [PMID: 29458300 DOI: 10.1080/17843286.2018.1436956] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES The roundworm Ascaris lumbricoides is one of the most prevalent parasites belonging to the class of the soil-transmitted helminths. Infections are most common in developing countries with a tropical climate where sanitation and hygiene are poor. However, prevalence of ascariasis in industrialized countries is increasing because of immigration and increasing number of refugees. METHODS We report a case of ascariasis in a female patient who was admitted to our hospital after she had left the informal refugee camp of Calais in the north of France. RESULTS After colonoscopic removal of the worm and treatment with mebendazole during three days the patient's symptoms had completely resolved. Medical treatment with benzimidazole derivatives is easy and inexpensive. To prevent parasitic infections in larger populations, mass drug administration should be repeated periodically and must be implemented along with additional measures such as improvements to water, sanitation and hygiene (WASH). These WASH programs have been proven to be highly effective, but access and follow-up are expensive and very difficult to organize in refugee camps, even in wealthy, industrialized countries. CONCLUSIONS Despite being an old, well-known parasitic disease, ascariasis might reappear in certain populations at risk in industrialized countries. Detection, treatment and follow-up of these patients, and the organization of preventive measures remain challenging.
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Affiliation(s)
- Paul-Emile Claus
- Clinical Laboratory of Microbiology, AZ Damiaan, Ostend, Belgium
| | | | - Mike Cool
- Department of Gastroenterology, AZ Damiaan, Ostend, Belgium
| | - Gudrun Alliet
- Clinical Laboratory of Microbiology, AZ Damiaan, Ostend, Belgium
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7
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Bouchery T, Filbey K, Shepherd A, Chandler J, Patel D, Schmidt A, Camberis M, Peignier A, Smith AAT, Johnston K, Painter G, Pearson M, Giacomin P, Loukas A, Bottazzi ME, Hotez P, LeGros G. A novel blood-feeding detoxification pathway in Nippostrongylus brasiliensis L3 reveals a potential checkpoint for arresting hookworm development. PLoS Pathog 2018; 14:e1006931. [PMID: 29566094 PMCID: PMC5864084 DOI: 10.1371/journal.ppat.1006931] [Citation(s) in RCA: 22] [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: 10/12/2017] [Accepted: 02/09/2018] [Indexed: 11/18/2022] Open
Abstract
As part of on-going efforts to control hookworm infection, the "human hookworm vaccine initiative" has recognised blood feeding as a feasible therapeutic target for inducing immunity against hookworm infection. To this end, molecular approaches have been used to identify candidate targets, such as Necator americanus (Na) haemoglobinase aspartic protease-1 (APR-1), with immunogenicity profiled in canine and hamster models. We sought to accelerate the immune analysis of these identified therapeutic targets by developing an appropriate mouse model. Here we demonstrate that Nippostrongylus brasiliensis (Nb), a phylogenetically distant strongylid nematode of rodents, begins blood feeding early in its development and that immunisation with Na-APR-1 can block its growth and completion of its life cycle. Furthermore, we identify a new haem detoxification pathway in Nb required for blood feeding that can be blocked by drugs of the quinolone family, reducing both infection burden and the associated anaemia in rodents. Collectively, our findings show that haem metabolism has potential as a checkpoint for interrupting hookworm development in early stages of the hookworm life cycle and that the Nippostrongylus brasiliensis rodent model is relevant for identifying novel therapeutic targets against human hookworm.
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Affiliation(s)
- Tiffany Bouchery
- Malaghan Institute of Medical Research, Wellington, New Zealand
- * E-mail: (GL); (TB)
| | - Kara Filbey
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Amy Shepherd
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Jodie Chandler
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Deepa Patel
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Alfonso Schmidt
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Mali Camberis
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | | | | | - Karen Johnston
- The Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, Wellington, New Zealand
| | - Gavin Painter
- The Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, Wellington, New Zealand
| | - Mark Pearson
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute for Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Paul Giacomin
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute for Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute for Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Maria-Elena Bottazzi
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children's Hospital Center for Vaccine Development, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Peter Hotez
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children's Hospital Center for Vaccine Development, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Graham LeGros
- Malaghan Institute of Medical Research, Wellington, New Zealand
- * E-mail: (GL); (TB)
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8
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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: 10] [Impact Index Per Article: 1.4] [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.
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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
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9
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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: 167] [Impact Index Per Article: 20.9] [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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10
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Sojka D, Hartmann D, Bartošová-Sojková P, Dvořák J. Parasite Cathepsin D-Like Peptidases and Their Relevance as Therapeutic Targets. Trends Parasitol 2016; 32:708-723. [PMID: 27344362 DOI: 10.1016/j.pt.2016.05.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/27/2016] [Accepted: 05/25/2016] [Indexed: 11/18/2022]
Abstract
Inhibition of aspartic cathepsin D-like peptidases (APDs) has been often discussed as an antiparasite intervention strategy. APDs have been considered as virulence factors of Trypanosoma cruzi and Leishmania spp., and have been demonstrated to have important roles in protein trafficking mechanisms of apicomplexan parasites. APDs also initiate blood digestion as components of multienzyme proteolytic complexes in malaria, platyhelminths, nematodes, and ticks. Increasing DNA and RNA sequencing data indicate that parasites express multiple APD isoenzymes of various functions that can now be specifically evaluated using new functional-genomic and biochemical tools, from which we can further assess the potential of APDs as targets for novel effective intervention strategies against parasitic diseases that still pose an alarming threat to mankind.
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Affiliation(s)
- Daniel Sojka
- Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice 370 05, Czech Republic.
| | - David Hartmann
- Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice 370 05, Czech Republic
| | - Pavla Bartošová-Sojková
- Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice 370 05, Czech Republic
| | - Jan Dvořák
- Institute of Molecular Genetics, The Czech Academy of Sciences, Prague 14220, Czech Republic; Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague 16610, Czech Republic; School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK
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Hotez PJ, Strych U, Lustigman S, Bottazzi ME. Human anthelminthic vaccines: Rationale and challenges. Vaccine 2016; 34:3549-55. [DOI: 10.1016/j.vaccine.2016.03.112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/23/2016] [Accepted: 03/31/2016] [Indexed: 12/29/2022]
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12
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Bartsch SM, Hotez PJ, Hertenstein DL, Diemert DJ, Zapf KM, Bottazzi ME, Bethony JM, Brown ST, Lee BY. Modeling the economic and epidemiologic impact of hookworm vaccine and mass drug administration (MDA) in Brazil, a high transmission setting. Vaccine 2016; 34:2197-206. [PMID: 27002501 DOI: 10.1016/j.vaccine.2016.03.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Although mass drug administration (MDA) has helped reduce morbidity attributed to soil-transmitted helminth infections in children, its limitations for hookworm infection have motivated the development of a human hookworm vaccine to both improve morbidity control and ultimately help block hookworm transmission leading to elimination. However, the potential economic and epidemiologic impact of a preventive vaccine has not been fully evaluated. METHODS We developed a dynamic compartment model coupled to a clinical and economics outcomes model representing both the human and hookworm populations in a high transmission region of Brazil. Experiments simulated different implementation scenarios of MDA and vaccination under varying circumstances. RESULTS Considering only intervention costs, both annual MDA and vaccination were highly cost-effective (ICERs ≤ $790/DALY averted) compared to no intervention, with vaccination resulting in lower incremental cost-effectiveness ratios (ICERs ≤ $444/DALY averted). From the societal perspective, vaccination was economically dominant (i.e., less costly and more effective) versus annual MDA in all tested scenarios, except when vaccination was less efficacious (20% efficacy, 5 year duration) and MDA coverage was 75%. Increasing the vaccine's duration of protection and efficacy, and including a booster injection in adulthood all increased the benefits of vaccination (i.e., resulted in lower hookworm prevalence, averted more disability-adjusted life years, and saved more costs). Assuming its target product profile, a pediatric hookworm vaccine drastically decreased hookworm prevalence in children to 14.6% after 20 years, compared to 57.2% with no intervention and 54.1% with MDA. The addition of a booster in adulthood further reduced the overall prevalence from 68.0% to 36.0% and nearly eliminated hookworm infection in children. CONCLUSION Using a human hookworm vaccine would be cost-effective and in many cases economically dominant, providing both health benefits and cost-savings. It could become a key technology in effecting control and elimination efforts for hookworm globally.
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Affiliation(s)
- Sarah M Bartsch
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Peter J Hotez
- National School of Tropical Medicine, and Departments of Pediatrics and Molecular Virology & Microbiology, Baylor College of Medicine, One Baylor Plaza, BCM113, Houston, TX 77030, USA; Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA
| | - Daniel L Hertenstein
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - David J Diemert
- Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA; Department of Microbiology, Immunology and Tropical Medicine, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Kristina M Zapf
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Maria Elena Bottazzi
- National School of Tropical Medicine, and Departments of Pediatrics and Molecular Virology & Microbiology, Baylor College of Medicine, One Baylor Plaza, BCM113, Houston, TX 77030, USA; Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA
| | - Jeffrey M Bethony
- Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA; Department of Microbiology, Immunology and Tropical Medicine, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Shawn T Brown
- Pittsburgh Supercomputing Center, Carnegie Mellon University, 300S Craig St, Pittsburgh, PA 15213, USA
| | - Bruce Y Lee
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA.
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Cantacessi C, Hofmann A, Campbell BE, Gasser RB. Impact of next-generation technologies on exploring socioeconomically important parasites and developing new interventions. Methods Mol Biol 2015; 1247:437-474. [PMID: 25399114 DOI: 10.1007/978-1-4939-2004-4_31] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
High-throughput molecular and computer technologies have become instrumental for systems biological explorations of pathogens, including parasites. For instance, investigations of the transcriptomes of different developmental stages of parasitic nematodes give insights into gene expression, regulation and function in a parasite, which is a significant step to understanding their biology, as well as interactions with their host(s) and disease. This chapter (1) gives a background on some key parasitic nematodes of socioeconomic importance, (2) describes sequencing and bioinformatic technologies for large-scale studies of the transcriptomes and genomes of these parasites, (3) provides some recent examples of applications and (4) emphasizes the prospects of fundamental biological explorations of parasites using these technologies for the development of new interventions to combat parasitic diseases.
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Affiliation(s)
- Cinzia Cantacessi
- Department of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
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Gaze S, Bethony JM, Periago MV. Immunology of experimental and natural human hookworm infection. Parasite Immunol 2014; 36:358-66. [PMID: 25337625 DOI: 10.1111/pim.12088] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human hookworm infection is one amongst the most prevalent of the neglected tropical diseases. An informative experimental animal model, that is, one that parallels a human infection, is not available for the study of human hookworm infection. Much of our current understanding of the human immune response during hookworm infection relies on the studies from experimental infection of hookworm-naïve individuals or the natural infections from individuals residing in hookworm-endemic areas. The experimental human infections tend to be acute, dose-controlled infections, often with a low larval inoculum so that they are well tolerated by human volunteers. Natural hookworm infections usually occur in areas where hookworm transmission is constant and infection is chronic. In cases where there has been drug administration in an endemic area, re-infection often occurs quickly even amongst those who were treated. Hence, although many of the characteristics of experimental and natural hookworm infection differ, both models have elements in common: mainly an intense Th2 response with the production of total and specific IgE as well as elevated levels of eosinophilia, IL-5, IL-10 and TNF. While hookworm infection affects millions of individuals worldwide, much of the human immunology of this infection still needs to be studied and understood.
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Immunization and challenge shown by hamsters infected with Opisthorchis viverrini following exposure to gamma-irradiated metacercariae of this carcinogenic liver fluke. J Helminthol 2014; 90:39-47. [PMID: 25315797 DOI: 10.1017/s0022149x14000741] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Here we report findings to optimize and standardize conditions to attenuate metacercariae of Opisthorchis viverrini by ionizing radiation to elicit protective immune responses to challenge infection. Metacercariae were gamma-irradiated and the ability of irradiated metacercariae to prevent patent infection of challenge metacercariae in hamsters was determined, as well as their ability to induce a host antibody response. Metacercariae irradiated in a dose-dependent manner, with 3, 5, 10, 12, 20, 25 and 50 Gray, were used to infect Syrian golden hamsters by stomach gavage to ascertain the effect of irradiation on ability of the worms to establish infection. In addition, other hamsters were infected with metacercariae irradiated with 20-50 Gray, followed by challenge with intact/wild-type (non-irradiated) metacercariae to determine the protective effect as established by the numbers of adult flukes, eggs of O. viverrini in hamster faeces and anti-O. viverrini antibody titres. Significantly fewer worms were recovered from hamsters immunized with metacercariae irradiated at 20, 25 and 50 Gray than from control hamsters infected with intact metacercariae or 0 Gray, and the worms showed damaged reproductive organs. Faecal egg numbers were decreased significantly in hamsters immunized with 25 and 50 Gray metacercariae of O. viverrini. Moreover, hamsters administered metacercariae that were protected elicited a robust, specific anti-fluke immunoglobulin G response compared to control hamsters, suggesting a role for antibody in protection elicited by radiation-attenuated metacercariae.
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16
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Dougall AM, Skwarczynski M, Khoshnejad M, Chandrudu S, Daly NL, Toth I, Loukas A. Lipid core peptide targeting the cathepsin D hemoglobinase of Schistosoma mansoni as a component of a schistosomiasis vaccine. Hum Vaccin Immunother 2013; 10:399-409. [PMID: 24231271 DOI: 10.4161/hv.27057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The self-adjuvanting lipid core peptide (LCP) system offers a safe alternative vaccine delivery strategy, eliminating the need for additional adjuvants such as CpG Alum. In this study, we adopted the LCP as a scaffold for an epitope located on the surface of the cathepsin D hemoglobinase (Sm-CatD) of the human blood fluke Schistosoma mansoni. Sm-CatD plays a pivotal role in digestion of the fluke's bloodmeal and has been shown to be efficacious as a subunit vaccine in a murine model of human schistosomiasis. Using molecular modeling we showed that S. mansoni cathepsin D possesses a predicted surface exposed α-helix (A₂₆₃K) that corresponds to an immunodominant helix and target of enzyme-neutralizing antibodies against Necator americanus APR-1 (Na-APR-1), the orthologous protease and vaccine antigen from blood-feeding hookworms. The A₂₆₃K epitope was engineered as two peptide variants, one of which was flanked at both termini with a coil maintaining sequence, thereby promoting the helical characteristics of the native A₂₆₃K epitope. Some of the peptides were fused to a self-adjuvanting lipid core scaffold to generate LCPs. Mice were vaccinated with unadjuvanted peptides, peptides formulated with Freund's adjuvants, or LCPs. Antibodies generated to LCPs recognized native Sm-CatD within a soluble adult schistosome extract, and almost completely abolished its enzymatic activity in vitro. Using immunohistochemistry we showed that anti-LCP antibodies bound to the native Sm-CatD protein in the esophagus and anterior regions of the gastrodermis of adult flukes. Vaccines offer an alternative control strategy in the fight against schistosomiasis, and further development of LCPs containing multiple epitopes from this and other vaccine antigens should become a research priority.
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Affiliation(s)
- Annette M Dougall
- Australian Institute of Tropical Health and Medicine; Centre for Biodiscovery and Molecular Development of Therapeutics; James Cook University; Cairns, QLD Australia
| | - Mariusz Skwarczynski
- Australian Institute of Tropical Health and Medicine; Centre for Biodiscovery and Molecular Development of Therapeutics; James Cook University; Cairns, QLD Australia; The University of Queensland; School of Chemistry and Molecular Biosciences; St. Lucia; QLD Australia; The University of Queensland; School of Pharmacy; Wooloongabba, QLD Australia
| | - Makan Khoshnejad
- The University of Queensland; School of Chemistry and Molecular Biosciences; St. Lucia; QLD Australia
| | - Saranya Chandrudu
- The University of Queensland; School of Chemistry and Molecular Biosciences; St. Lucia; QLD Australia
| | - Norelle L Daly
- Australian Institute of Tropical Health and Medicine; Centre for Biodiscovery and Molecular Development of Therapeutics; James Cook University; Cairns, QLD Australia
| | - Istvan Toth
- Australian Institute of Tropical Health and Medicine; Centre for Biodiscovery and Molecular Development of Therapeutics; James Cook University; Cairns, QLD Australia; The University of Queensland; School of Chemistry and Molecular Biosciences; St. Lucia; QLD Australia; The University of Queensland; School of Pharmacy; Wooloongabba, QLD Australia
| | - Alex Loukas
- Australian Institute of Tropical Health and Medicine; Centre for Biodiscovery and Molecular Development of Therapeutics; James Cook University; Cairns, QLD Australia
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Beaumier CM, Gillespie PM, Hotez PJ, Bottazzi ME. New vaccines for neglected parasitic diseases and dengue. Transl Res 2013; 162:144-55. [PMID: 23578479 DOI: 10.1016/j.trsl.2013.03.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/15/2013] [Accepted: 03/16/2013] [Indexed: 01/13/2023]
Abstract
Neglected tropical diseases (NTDs) are a significant source of morbidity and socioeconomic burden among the world's poor. Virtually all of the 2.4 billion people who live on less than $2 per d, more than a third of the world's population, are at risk for these debilitating NTDs. Although chemotherapeutic measures exist for many of these pathogens, they are not sustainable countermeasures on their own because of rates of reinfection, risk of drug resistance, and inconsistent maintenance of drug treatment programs. Preventative and therapeutic NTD vaccines are needed as long-term solutions. Because there is no market in the for-profit sector of vaccine development for these pathogens, much of the effort to develop vaccines is driven by nonprofit entities, mostly through product development partnerships. This review describes the progress of vaccines under development for many of the NTDs, with a specific focus on those about to enter or that are currently in human clinical trials. Specifically, we report on the progress on dengue, hookworm, leishmaniasis, schistosomiasis, Chagas disease, and onchocerciasis vaccines. These products will be some of the first with specific objectives to aid the world's poorest populations.
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Affiliation(s)
- Coreen M Beaumier
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, National School of Tropical Medicine, Baylor College of Medicine, Houston 77030, Tex., USA
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Curti E, Kwityn C, Zhan B, Gillespie P, Brelsford J, Deumic V, Plieskatt J, Rezende WC, Tsao E, Kalampanayil B, Hotez PJ, Bottazzi ME. Expression at a 20L scale and purification of the extracellular domain of the Schistosoma mansoni TSP-2 recombinant protein: a vaccine candidate for human intestinal schistosomiasis. Hum Vaccin Immunother 2013; 9:2342-50. [PMID: 23899507 DOI: 10.4161/hv.25787] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A novel recombinant protein vaccine for human schistosomiasis caused by Schistosoma mansoni is under development. The Sm-TSP-2 schistosomiasis vaccine is comprised of a 9 kDa recombinant protein corresponding to the extracellular domain of a unique S. mansoni tetraspanin. Here, we describe the cloning and the expression of the external loop of Sm-TSP-2 recombinant protein secreted by Pichia Pink the process development at 20L scale fermentation, and the two-steps purification, which resulted in a protein recovery yield of 31% and a protein purity of 97%. The developed processes are suitable for the production of purified protein for subsequent formulation and Phase 1 clinical studies.
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Affiliation(s)
- Elena Curti
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA; Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX USA
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19
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Kalinna B, Walduck A. Subversion of immunity by schistosomes. MICROBIOLOGY AUSTRALIA 2013. [DOI: 10.1071/ma13046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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20
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Torben W, Ahmad G, Zhang W, Nash S, Le L, Karmakar S, Siddiqui AA. Role of antibody dependent cell mediated cytotoxicity (ADCC) in Sm-p80-mediated protection against Schistosoma mansoni. Vaccine 2012; 30:6753-8. [PMID: 23000221 DOI: 10.1016/j.vaccine.2012.09.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/07/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
Abstract
Schistosomiasis is a major health problem in the developing world and for international travelers to the endemic countries. Existing strategies to control schistosomiasis have had limited successes so far. The addition of an effective vaccine in existing control measures would be greatly beneficial in reducing the impact of the disease. In this regard, Sm-p80 mediated protection against intestinal schistosomiasis caused by Schistosoma mansoni has been observed to be promising in two animal models of infection and disease. In this study, the role of antibody dependent cell mediated cytotoxicity (ADCC) was deciphered in Sm-p80-mediated protection especially in the elimination of lung stage schistosomula. This was achieved using lung lavage cells and lung cells that were isolated from mice immunized with and without Sm-p80 formulated in a recombinant vaccine formulation. Significant differences were observed in cytotoxicity assays using immune sera with the lung lavage cells which showed 51% more killing of schistosomula and elevated levels of nitric oxide in the supernatants were detected compared to controls.
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Affiliation(s)
- Workineh Torben
- Center for Tropical Medicine and Infectious Diseases, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Pearson MS, Tribolet L, Cantacessi C, Periago MV, Valero MA, Valerio MA, Jariwala AR, Hotez P, Diemert D, Loukas A, Bethony J. Molecular mechanisms of hookworm disease: stealth, virulence, and vaccines. J Allergy Clin Immunol 2012; 130:13-21. [PMID: 22742835 DOI: 10.1016/j.jaci.2012.05.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 12/31/2022]
Abstract
Hookworms produce a vast repertoire of structurally and functionally diverse molecules that mediate their long-term survival and pathogenesis within a human host. Many of these molecules are secreted by the parasite, after which they interact with critical components of host biology, including processes that are key to host survival. The most important of these interactions is the hookworm's interruption of nutrient acquisition by the host through its ingestion and digestion of host blood. This results in iron deficiency and eventually the microcytic hypochromic anemia or iron deficiency anemia that is the clinical hallmark of hookworm infection. Other molecular mechanisms of hookworm infection cause a systematic suppression of the host immune response to both the parasite and to bystander antigens (eg, vaccines or allergens). This is achieved by a series of molecules that assist the parasite in the stealthy evasion of the host immune response. This review will summarize the current knowledge of the molecular mechanisms used by hookworms to survive for extended periods in the human host (up to 7 years or longer) and examine the pivotal contributions of these molecular mechanisms to chronic hookworm parasitism and host clinical outcomes.
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Affiliation(s)
- Mark S Pearson
- Center for Biodiscovery and Molecular Development of Therapeutics, James Cook University, Cairns, Australia.
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Interaction of Schistosoma mansoni Sporocysts and Hemocytes of Biomphalaria. J Parasitol Res 2012; 2012:743920. [PMID: 22811885 PMCID: PMC3395257 DOI: 10.1155/2012/743920] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 05/18/2012] [Indexed: 12/11/2022] Open
Abstract
Human infection by Schistosoma mansoni affects more than 100 million people worldwide, most often in populations of developing countries of Africa, Asia, and Latin America. The transmission of S. mansoni in human populations depends on the presence of some species of Biomphalaria that act as an intermediate host. The compatibility between S. mansoni and its intermediate host is influenced by behavioral, physiological, and genetical factors of the mollusc and the parasite. The susceptibility level of the mollusc has been attributed to the capacity of internal defense system (IDS)—hemocytes and soluble components of the hemolymph—to recognize and destroy the parasite, and this will be the center of interest of this paper. The schistosome-resistant Biomphalaria can be an alternative strategy for the control of schistosomiasis.
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Cantacessi C, Campbell BE, Gasser RB. Key strongylid nematodes of animals — Impact of next-generation transcriptomics on systems biology and biotechnology. Biotechnol Adv 2012; 30:469-88. [DOI: 10.1016/j.biotechadv.2011.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 08/09/2011] [Accepted: 08/19/2011] [Indexed: 10/17/2022]
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Prichard RK, Basáñez MG, Boatin BA, McCarthy JS, García HH, Yang GJ, Sripa B, Lustigman S. A research agenda for helminth diseases of humans: intervention for control and elimination. PLoS Negl Trop Dis 2012; 6:e1549. [PMID: 22545163 PMCID: PMC3335868 DOI: 10.1371/journal.pntd.0001549] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recognising the burden helminth infections impose on human populations, and particularly the poor, major intervention programmes have been launched to control onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, and cysticercosis. The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. A summary of current helminth control initiatives is presented and available tools are described. Most of these programmes are highly dependent on mass drug administration (MDA) of anthelmintic drugs (donated or available at low cost) and require annual or biannual treatment of large numbers of at-risk populations, over prolonged periods of time. The continuation of prolonged MDA with a limited number of anthelmintics greatly increases the probability that drug resistance will develop, which would raise serious problems for continuation of control and the achievement of elimination. Most initiatives have focussed on a single type of helminth infection, but recognition of co-endemicity and polyparasitism is leading to more integration of control. An understanding of the implications of control integration for implementation, treatment coverage, combination of pharmaceuticals, and monitoring is needed. To achieve the goals of morbidity reduction or elimination of infection, novel tools need to be developed, including more efficacious drugs, vaccines, and/or antivectorial agents, new diagnostics for infection and assessment of drug efficacy, and markers for possible anthelmintic resistance. In addition, there is a need for the development of new formulations of some existing anthelmintics (e.g., paediatric formulations). To achieve ultimate elimination of helminth parasites, treatments for the above mentioned helminthiases, and for taeniasis and food-borne trematodiases, will need to be integrated with monitoring, education, sanitation, access to health services, and where appropriate, vector control or reduction of the parasite reservoir in alternative hosts. Based on an analysis of current knowledge gaps and identification of priorities, a research and development agenda for intervention tools considered necessary for control and elimination of human helminthiases is presented, and the challenges to be confronted are discussed.
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Plieskatt JL, Rezende WC, Olsen CM, Trefethen JM, Joshi SB, Middaugh CR, Hotez PJ, Bottazzi ME. Advances in vaccines against neglected tropical diseases: enhancing physical stability of a recombinant hookworm vaccine through biophysical and formulation studies. Hum Vaccin Immunother 2012; 8:765-76. [PMID: 22495115 DOI: 10.4161/hv.19726] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A bivalent recombinant vaccine for human hookworm disease is under development. One of the lead candidate antigens in the vaccine is a glutathione S-transferase cloned from the hookworm Necator americanus (Na-GST-1) which is expressed in the yeast Pichia pastoris. Based on preliminary studies demonstrating that the recombinant protein was not stable in an acetate buffer at pH 6, we undertook an extensive stability analysis of the molecule. To improve and optimize stability we complemented traditional methods employed for macromolecule and vaccine stabilization with biophysical techniques that were incorporated into a systematic process based on an eigenvector approach. Large data sets, obtained from a variety of experimental methods were used to establish a color map ("empirical phase diagram") of the physical stability of the vaccine antigen over a wide range of temperature and pH. The resulting map defined "apparent phase boundaries" that were used to develop high throughput screening assays. These assays were then employed to identify excipients that stabilized the antigen against physical degradation that could otherwise result in losses of physicochemical integrity, immunogenicity, and potency of the vaccine. Based on these evaluations, the recombinant Na-GST-1 antigen was reformulated and ultimately produced under Good Manufacturing Practices and with an acceptable stability profile.
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Affiliation(s)
- Jordan L Plieskatt
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, USA.
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Pearson MS, Pickering DA, McSorley HJ, Bethony JM, Tribolet L, Dougall AM, Hotez PJ, Loukas A. Enhanced protective efficacy of a chimeric form of the schistosomiasis vaccine antigen Sm-TSP-2. PLoS Negl Trop Dis 2012; 6:e1564. [PMID: 22428079 PMCID: PMC3302818 DOI: 10.1371/journal.pntd.0001564] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 01/27/2012] [Indexed: 01/04/2023] Open
Abstract
The large extracellular loop of the Schistosoma mansoni tetraspanin, Sm-TSP-2, when fused to a thioredoxin partner and formulated with Freund's adjuvants, has been shown to be an efficacious vaccine against murine schistosomiasis. Moreover, Sm-TSP-2 is uniquely recognised by IgG1 and IgG3 from putatively resistant individuals resident in S. mansoni endemic areas in Brazil. In the present study, we expressed Sm-TSP-2 at high yield and in soluble form in E. coli without the need for a solubility enhancing fusion partner. We also expressed in E. coli a chimera called Sm-TSP-2/5B, which consisted of Sm-TSP-2 fused to the immunogenic 5B region of the hookworm aspartic protease and vaccine antigen, Na-APR-1. Sm-TSP-2 formulated with alum/CpG showed significant reductions in adult worm and liver egg burdens in two separate murine schistosomiasis challenge studies. Sm-TSP-2/5B afforded significantly greater protection than Sm-TSP-2 alone when both antigens were formulated with alum/CpG. The enhanced protection obtained with the chimeric fusion protein was associated with increased production of anti-Sm-TSP-2 antibodies and IL-4, IL-10 and IFN-γ from spleen cells of vaccinated animals. Sera from 666 individuals from Brazil who were infected with S. mansoni were screened for potentially deleterious IgE responses to Sm-TSP-2. Anti-Sm-TSP-2 IgE to this protein was not detected (also shown previously for Na-APR-1), suggesting that the chimeric antigen Sm-TSP-2/5B could be used to safely and effectively vaccinate people in areas where schistosomes and hookworms are endemic. There are currently no vaccines available to combat helminth (worm) infections in humans. The most devastating of the diseases caused by human helminths are schistosomiasis (or bilharzia) and hookworm disease. By fusing one of the lead schistosomiasis vaccine antigens, Sm-TSP-2, with a protective fragment from one of the lead hookworm vaccine antigens, Na-APR-1, we have produced a chimeric vaccine, termed Sm-TSP-2/5B that might provide protection against two debilitating and co-endemic neglected tropical diseases. Sm-TSP-2/5B provided increased protection compared to Sm-TSP-2 alone when formulated with human approved adjuvants and tested in a mouse model of schistosomiasis. Moreover, IgE against Sm-TSP-2 or Na-APR-1 has not been detected in the blood of residents from an area in Brazil that is endemic for schistosomes and hookworms, indicating that vaccines based on these molecules would be unlikely to generate allergic reactions in recipients from developing countries.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Adolescent
- Adult
- Aged
- Alum Compounds/administration & dosage
- Animals
- Antibodies, Helminth/blood
- Antigens, Helminth/administration & dosage
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Aspartic Acid Proteases/administration & dosage
- Aspartic Acid Proteases/genetics
- Aspartic Acid Proteases/immunology
- Brazil
- Child
- Child, Preschool
- Cytokines/metabolism
- Disease Models, Animal
- Escherichia coli/genetics
- Female
- Gene Expression
- Humans
- Immunoglobulin G/blood
- Infant
- Leukocytes, Mononuclear/immunology
- Male
- Mice
- Mice, Inbred C57BL
- Middle Aged
- Oligodeoxyribonucleotides/administration & dosage
- Recombinant Fusion Proteins/administration & dosage
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Schistosomiasis/immunology
- Schistosomiasis/prevention & control
- Spleen/immunology
- Tetraspanins/administration & dosage
- Tetraspanins/genetics
- Tetraspanins/immunology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/immunology
- Young Adult
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Affiliation(s)
- Mark S. Pearson
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Darren A. Pickering
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Henry J. McSorley
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Jeffrey M. Bethony
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington D.C., United States of America
| | - Leon Tribolet
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Annette M. Dougall
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Peter J. Hotez
- Department of Pediatrics and Molecular Virology and Microbiology, and National School of Tropical Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alex Loukas
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
- * E-mail:
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27
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Enlarging the "Audacious Goal": elimination of the world's high prevalence neglected tropical diseases. Vaccine 2011; 29 Suppl 4:D104-10. [PMID: 22188933 DOI: 10.1016/j.vaccine.2011.06.024] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 06/01/2011] [Accepted: 06/09/2011] [Indexed: 12/22/2022]
Abstract
The high prevalence neglected tropical diseases (NTDs) exhibit a global disease burden that exceeds malaria, tuberculosis, and other better known global health conditions; they also represent a potent force in trapping the world's poorest people in poverty. Through extremely low cost national programs of disease mapping and mass drug administration (MDA) for the seven most common NTDs, integrated NTD control and elimination efforts are now in place in more than 14 countries through the support of the United States Agency for International Development (USAID), the British Department for International Development (DFID), and the Global Network for NTDs and its partners. The World Health Organization (WHO) estimates that in 2008 some 670 million people in 75 countries received NTD treatments through these and other sponsored programs. With continued successes the next decade could witness the global elimination of blinding trachoma, human Africa trypanosomiasis (HAT), lymphatic filariasis (LF), onchocerciasis, trachoma, and leprosy as public health problems, in addition to the eradication of dracunculiasis. For other high prevalence NTDs, including hookworm infection, schistosomiasis, Chagas disease and leishmaniasis, new drugs and vaccines may still be required. Increasingly it is recognized that the high prevalence NTDs exhibit extensive geographic overlap and polyparasitism is commonly found throughout the world's low income countries. Therefore, global elimination will also require integrated packages of drugs together with vaccine-linked chemotherapy. Ultimately, the global elimination of the high prevalence NTDs will require continued large-scale support from the U.S. Government and selected European governments, however, the emerging market economies, such as Brazil, China, India, Mexico, and Nigeria, and wealthy countries in the Middle East will also have to substantially contribute.
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28
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Molecular cloning and characterization of a HSP70 gene from Schistosoma japonicum. Parasitol Res 2011; 110:1785-93. [DOI: 10.1007/s00436-011-2700-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 10/13/2011] [Indexed: 11/26/2022]
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29
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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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30
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Wilson MS, Cheever AW, White SD, Thompson RW, Wynn TA. IL-10 blocks the development of resistance to re-infection with Schistosoma mansoni. PLoS Pathog 2011; 7:e1002171. [PMID: 21829367 PMCID: PMC3150278 DOI: 10.1371/journal.ppat.1002171] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 06/03/2011] [Indexed: 01/26/2023] Open
Abstract
Despite effective chemotherapy to treat schistosome infections, re-infection rates are extremely high. Resistance to reinfection can develop, however it typically takes several years following numerous rounds of treatment and re-infection, and often develops in only a small cohort of individuals. Using a well-established and highly permissive mouse model, we investigated whether immunoregulatory mechanisms influence the development of resistance. Following Praziquantel (PZQ) treatment of S. mansoni infected mice we observed a significant and mixed anti-worm response, characterized by Th1, Th2 and Th17 responses. Despite the elevated anti-worm response in PBMC's, liver, spleen and mesenteric lymph nodes, this did not confer any protection from a secondary challenge infection. Because a significant increase in IL-10-producing CD4+CD44+CD25+GITR+ lymphocytes was observed, we hypothesised that IL-10 was obstructing the development of resistance. Blockade of IL-10 combined with PZQ treatment afforded a greater than 50% reduction in parasite establishment during reinfection, compared to PZQ treatment alone, indicating that IL-10 obstructs the development of acquired resistance. Markedly enhanced Th1, Th2 and Th17 responses, worm-specific IgG1, IgG2b and IgE and circulating eosinophils characterized the protection. This study demonstrates that blocking IL-10 signalling during PZQ treatment can facilitate the development of protective immunity and provide a highly effective strategy to protect against reinfection with S. mansoni. Schistosomes are zoonotic parasitic helminths that infect hundreds of millions of people worldwide. Despite effective chemotherapy, schistosomiasis- the disease caused by these parasites, still plagues tropical regions of the world. This is due, in part, to poor resistance to reinfection resulting in high re-infection rates following treatment. This lack of resistance is intriguing, as effective treatment relies upon drug-induced parasite damage combined with host immune mediated killing. Furthermore, it has been widely reported that post-treatment, individuals develop and retain elevated levels of anti-parasite immune responses. We therefore asked why resistance to re-infection is so poor, despite the development of significant anti-worm responses post-treatment. It is essential that immune responses are controlled by various immunosuppressive mechanisms to prevent immune-mediated pathologies. However, a robust immunoregulatory response may obstruct the development of protective immunity. Thus, a balanced immune response providing a non-pathogenic yet effective immune response may be required for the development of effective resistance to reinfection. Understanding the immunological mechanisms of resistance to re-infection and the role of effector and regulatory responses may aid in the development of more effective vaccines and treatment strategies for schistosomaisis. This study suggests that combining chemotherapy with drugs that block IL-10 might provide an improved strategy to elicit acquired immunity to this parasite.
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Affiliation(s)
- Mark S Wilson
- Immunopathogensis Section, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Marlyand, United States of America.
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31
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Singh AN, Liu W, Hao G, Kumar A, Gupta A, Öz OK, Hsieh JT, Sun X. Multivalent bifunctional chelator scaffolds for gallium-68 based positron emission tomography imaging probe design: signal amplification via multivalency. Bioconjug Chem 2011; 22:1650-62. [PMID: 21740059 DOI: 10.1021/bc200227d] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The role of the multivalent effect has been well recognized in the design of molecular imaging probes toward the desired imaging signal amplification. Recently, we reported a bifunctional chelator (BFC) scaffold design, which provides a simple and versatile approach to impart multivalency to radiometal based nuclear imaging probes. In this work, we report a series of BFC scaffolds ((t)Bu(3)-1-COOH, (t)Bu(3)-2-(COOH)(2), and (t)Bu(3)-3-(COOH)(3)) constructed on the framework of 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) for (68)Ga-based PET probe design and signal amplification via the multivalent effect. For proof of principle, a known integrin α(v)β(3) specific ligand (c(RGDyK)) was used to build the corresponding NOTA conjugates (H(3)1, H(3)2, and H(3)3), which present 1-3 copies of c(RGDyK) peptide, respectively, in a systematic manner. Using the integrin α(v)β(3) binding affinities (IC(50) values), enhanced specific binding was observed for multivalent conjugates (H(3)2: 43.9 ± 16.1 nM; H(3)3: 14.7 ± 5.0 nM) as compared to their monovalent counterpart (H(3)1: 171 ± 60 nM) and the intact c(RGDyK) peptide (204 ± 76 nM). The obtained conjugates were efficiently labeled with (68)Ga(3+) within 30 min at room temperature in high radiochemical yields (>95%). The in vivo evaluation of the labeled conjugates, (68)Ga-1, (68)Ga-2, and (68)Ga-3, was performed using male severe combined immunodeficiency (SCID) mice bearing integrin α(v)β(3) positive PC-3 tumor xenografts (n = 3). All (68)Ga-labeled conjugates showed high in vivo stability with no detectable metabolites found by radio-HPLC within 2 h postinjection (p.i.). The PET signal amplification in PC-3 tumor by the multivalent effect was clearly displayed by the tumor uptake of the (68)Ga-labeled conjugates ((68)Ga-3: 2.55 ± 0.50%ID/g; (68)Ga-2: 1.90 ± 0.10%ID/g; (68)Ga-1: 1.66 ± 0.15%ID/g) at 2 h p.i. In summary, we have designed and synthesized a series of NOTA-based BFC scaffolds with signal amplification properties, which may find potential applications as diagnostic gallium radiopharmaceuticals.
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Affiliation(s)
- Ajay N Singh
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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32
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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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33
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Loukas A, Gaze S, Mulvenna JP, Gasser RB, Brindley PJ, Doolan DL, Bethony JM, Jones MK, Gobert GN, Driguez P, McManus DP, Hotez PJ. Vaccinomics for the major blood feeding helminths of humans. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2011; 15:567-77. [PMID: 21679087 DOI: 10.1089/omi.2010.0150] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Approximately one billion people are infected with hookworms and/or blood flukes (schistosomes) in developing countries. These two parasites are responsible for more disability adjusted life years lost than most other neglected tropical diseases (NTDs), and together, are second only to malaria. Although anthelmintic drugs are effective and widely available, they do not protect against reinfection, resistant parasites are likely to emerge, and mass drug administration programs are unsustainable. Therefore, there is a pressing need for the development of vaccines against these parasites. In recent years, there have been major advances in our understanding of hookworms and schistosomes at the molecular level through the use of "omics" technologies. The secretomes of these parasites have been characterized using transcriptomics, genomics, proteomics, and newly developed gene manipulation and silencing techniques, and the proteins of interest are now the target of novel antigen discovery approaches, notably immunomics. This research has resulted in the discovery, development, and early stage clinical trials of subunit vaccines against hookworms and schistosomes.
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Affiliation(s)
- Alex Loukas
- Queensland Tropical Health Alliance, James Cook University, Cairns, Queensland, Australia.
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34
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Alexander N, Cundill B, Sabatelli L, Bethony JM, Diemert D, Hotez P, Smith PG, Rodrigues LC, Brooker S. Selection and quantification of infection endpoints for trials of vaccines against intestinal helminths. Vaccine 2011; 29:3686-94. [PMID: 21435404 PMCID: PMC3093614 DOI: 10.1016/j.vaccine.2011.03.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/21/2011] [Accepted: 03/02/2011] [Indexed: 12/22/2022]
Abstract
Vaccines against human helminths are being developed but the choice of optimal parasitological endpoints and effect measures to assess their efficacy has received little attention. Assuming negative binomial distributions for the parasite counts, we rank the statistical power of three measures of efficacy: ratio of mean parasite intensity at the end of the trial, the odds ratio of infection at the end of the trial, and the rate ratio of incidence of infection during the trial. We also use a modelling approach to estimate the likely impact of trial interventions on the force of infection, and hence statistical power. We conclude that (1) final mean parasite intensity is a suitable endpoint for later phase vaccine trials, and (2) mass effects of trial interventions are unlikely to appreciably reduce the force of infection in the community - and hence statistical power - unless there is a combination of high vaccine efficacy and a large proportion of the population enrolled.
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Affiliation(s)
- Neal Alexander
- London School of Hygiene and Tropical Medicine, London, UK.
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35
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Torben W, Ahmad G, Zhang W, Siddiqui AA. Role of antibodies in Sm-p80-mediated protection against Schistosoma mansoni challenge infection in murine and nonhuman primate models. Vaccine 2011; 29:2262-71. [PMID: 21277404 DOI: 10.1016/j.vaccine.2011.01.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/23/2010] [Accepted: 01/13/2011] [Indexed: 01/23/2023]
Abstract
Schistosomiasis is an important public health concern in more than 76 developing countries. Advent of an anti-schistosome vaccine would undoubtedly add to the existing control measures and may eventually help in the elimination of this disease. In the present study we have attempted to dissect the role(s) of antibodies in Sm-p80 mediated protection by intravenously transferring pooled sera from mice immunized with Sm-p80-pcDNA3 or purified IgG from baboons immunized with Sm-p80-pcDNA3, into naïve C57BL/6 mice, respectively, prior to challenge with cercariae. The passive transfer of antibodies from protected mice (homologous transfers) as well as transfer of total IgG from baboons (heterologous transfers), into naïve mice showed statistically significant reductions in worm burden and in the number of eggs in the tissues. Immunizations of antibody knockout mice (μMt-/-; B10.129S2 (B6)-Igh-6(tm1Cgn)/J) with recombinant Sm-p80 in the presence of CpG-motif oligodeoxynucleotides as an adjuvant, resulted in substantial reduction of Sm-p80-mediated protection, compared to C57BL/6 (normal) control group of mice. Down regulation of cytokines that have important effects on B cell proliferation as well as the recovery of higher number of parasites in antibody knockout indicated a significant role(s) of antibodies in Sm-p80-mediated protection against Schistosoma mansoni in mice. In toto, these studies appear to suggest that antibodies play a significant role in Sm-p80 mediated protection.
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Affiliation(s)
- Workineh Torben
- Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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36
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Knox D. Proteases in blood-feeding nematodes and their potential as vaccine candidates. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 712:155-76. [PMID: 21660664 DOI: 10.1007/978-1-4419-8414-2_10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Parasitic nematodes express and secrete a variety of proteases which they use for many purposes including the penetration of host tissues, digestion of host protein for nutrients, evasion of host immune responses and for internal processes such as tissue catabolism and apoptosis. For these broad reasons they have been examined as possible parasite control targets. Blood-feeding nematodes such as the barber-pole worm Haemonchus contortus that infect sheep and goats and the hookworms, Ancylostoma spp. and Necator americanus, affecting man, use an array of endo- and exopeptidases to digest the blood meal. Haemoglobin digestion occurs by an ordered and partly conserved proteolytic cascade. These proteases are accessible to host immune responses which can block enzyme function and lead to parasite expulsion and/or death. Thus they are receiving attention as components of vaccines against several parasitic nematodes of social and economic importance.
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Affiliation(s)
- David Knox
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland, UK.
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37
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The potential economic value of a hookworm vaccine. Vaccine 2010; 29:1201-10. [PMID: 21167860 DOI: 10.1016/j.vaccine.2010.12.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 10/20/2010] [Accepted: 12/01/2010] [Indexed: 11/23/2022]
Abstract
Hookworm infection is a significant problem worldwide. As development of hookworm vaccine proceeds, it is essential for vaccine developers and manufacturers, policy makers, and other public health officials to understand the potential costs and benefits of such a vaccine. We developed a decision analytic model to evaluate the cost-effectiveness of introducing a hookworm vaccine into two populations in Brazil: school-age children and non-pregnant women of reproductive age. Results suggest that a vaccine would provide not only cost savings, but potential health benefits to both populations. In fact, the most cost-effective intervention strategy may be to combine vaccine with current drug treatment strategies.
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38
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Developing vaccines to combat hookworm infection and intestinal schistosomiasis. Nat Rev Microbiol 2010; 8:814-26. [PMID: 20948553 DOI: 10.1038/nrmicro2438] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hookworm infection and schistosomiasis rank among the most important health problems in developing countries. Both cause anaemia and malnutrition, and schistosomiasis also results in substantial intestinal, liver and genitourinary pathology. In sub-Saharan Africa and Brazil, co-infections with the hookworm, Necator americanus, and the intestinal schistosome, Schistosoma mansoni, are common. The development of vaccines for these infections could substantially reduce the global disability associated with these helminthiases. New genomic, proteomic, immunological and X-ray crystallographic data have led to the discovery of several promising candidate vaccine antigens. Here, we describe recent progress in this field and the rationale for vaccine development.
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39
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Wang X, Zhang L, Chi Y, Hoellwarth J, Zhou S, Wen X, He L, Liu F, Wu C, Su C. The nature and combination of subunits used in epitope-based Schistosoma japonicum vaccine formulations affect their efficacy. Parasit Vectors 2010; 3:109. [PMID: 21087526 PMCID: PMC3136145 DOI: 10.1186/1756-3305-3-109] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 11/19/2010] [Indexed: 01/07/2023] Open
Abstract
Background Schistosomiasis remains a major public health problem in endemic countries and is caused by infections with any one of three primary schistosome species. Although there are no vaccines available to date, this strategy appears feasible since natural immunity develops in individuals suffering from repeated infection during a lifetime. Since vaccinations resulting in both Th1- and Th2-type responses have been shown to contribute to protective immunity, a vaccine formulation with the capacity for stimulating multiple arms of the immune response will likely be the most effective. Previously we developed partially protective, single Th- and B cell-epitope-based peptide-DNA dual vaccines (PDDV) (T3-PDDV and B3-PDDV, respectively) capable of eliciting immune responses against the Schistosoma japonicum 22.6 kDa tegument antigen (Sj22.6) and a 62 kDa fragment of myosin (Sj62), respectively. Results In this study, we developed PDDV cocktails containing multiple epitopes of S. japonicum from Sj22.6, Sj62 and Sj97 antigens by predicting cytotoxic, helper, and B-cell epitopes, and evaluated vaccine potential in vivo. Results showed that mice immunized with a single-epitope PDDV elicited either Tc, Th, or B cell responses, respectively, and mice immunized with either the T3- or B3- single-epitope PDDV formulation were partially protected against infection. However, mice immunized with a multicomponent (3 PDDV components) formulation elicited variable immune responses that were less immunoprotective than single-epitope PDDV formulations. Conclusions Our data show that combining these different antigens did not result in a more effective vaccine formulation when compared to each component administered individually, and further suggest that immune interference resulting from immunizations with antigenically distinct vaccine targets may be an important consideration in the development of multicomponent vaccine preparations.
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Affiliation(s)
- Xuefeng Wang
- Department of Pathogen Biology and Immunology, Jiangsu Key Laboratory of Pathogen Biology, Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu 210029, PR China.
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Tchoubrieva EB, Ong PC, Pike RN, Brindley PJ, Kalinna BH. Vector-based RNA interference of cathepsin B1 in Schistosoma mansoni. Cell Mol Life Sci 2010; 67:3739-48. [PMID: 20339897 PMCID: PMC11115793 DOI: 10.1007/s00018-010-0345-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 10/19/2022]
Abstract
In helminth parasites, proteolytic enzymes have been implicated in facilitating host invasion, moulting, feeding, and evasion of the host immune response. These key functions render them potential targets for anti-parasite chemotherapy and immunotherapy. Schistosomes feed on host blood and the digested haemoglobin is their major source of amino acids. Haemoglobin digestion is essential for parasite development, growth, and reproduction. We recently reported the use of pseudotyped Moloney murine leukaemia virus to accomplish transformation of Schistosoma mansoni. Here, we report the design of a viral vector expressing a dsRNA hairpin to silence expression of the schistosome cathepsin B1 (SmCB1) gene. We observed 80% reduction in transcript level 72 h after virus exposure and complete silencing of enzyme activity in transduced worms. This is the first report using this technology in any helminth parasite. It will facilitate the evaluation of potential drug targets and biochemical pathways for novel interventions in schistosomes.
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Affiliation(s)
- Elissaveta B. Tchoubrieva
- Centre for Animal Biotechnology, Faculty of Veterinary Science, The University of Melbourne, Parkville, VIC 3052 Australia
| | - Poh C. Ong
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800 Australia
| | - Robert N. Pike
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800 Australia
| | - Paul J. Brindley
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University Medical Centre, Washington, DC 20037 USA
| | - Bernd H. Kalinna
- Centre for Animal Biotechnology, Faculty of Veterinary Science, The University of Melbourne, Parkville, VIC 3052 Australia
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Vandemark LM, Jia TW, Zhou XN. Social science implications for control of helminth infections in Southeast Asia. ADVANCES IN PARASITOLOGY 2010; 73:137-70. [PMID: 20627142 DOI: 10.1016/s0065-308x(10)73006-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Social science perspectives can inform helminth disease control in Southeast Asia. The social science literature offers theoretical and conceptual models; research methods; recommendations for training and capacity building, health education and health care professional training; and practice guidelines, including implementation of evidence-based interventions. Priority themes include poverty, gender differences, health inequities and access to social resources. Implications for helminth control include broadening disease monitoring and surveillance to include social and economic variables and subjective measures of well-being; training for health professionals and researchers in the social determinants of health; and application of social science models, specifically the expanded 'Chronic Care Model', to the planning and evaluation of interventions. The chapter posits that helminth diseases meet the World Health Organization's expanded definition of chronic conditions, and that integrated delivery of multiple interventions is needed to address the full range of risks and outcomes due to helminth infection.
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Affiliation(s)
- Lisa M Vandemark
- College of Health and Human Services, George Mason University, USA
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Pearson MS, Ranjit N, Loukas A. Blunting the knife: development of vaccines targeting digestive proteases of blood-feeding helminth parasites. Biol Chem 2010; 391:901-11. [DOI: 10.1515/bc.2010.074] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractProteases are pivotal to parasitism, mediating biological processes crucial to worm survival including larval migration through tissue, immune evasion/modulation and nutrient acquisition by the adult parasite. In haematophagous parasites, many of these proteolytic enzymes are secreted from the intestine (nematodes) or gastrodermis (trematodes) where they act to degrade host haemoglobin and serum proteins as part of the feeding process. These proteases are exposed to components of the immune system of the host when the worms ingest blood, and therefore present targets for the development of anti-helminth vaccines. The protective effects of current vaccine antigens against nematodes that infect humans (hookworm) and livestock (barber's pole worm) are based on haemoglobin-degrading intestinal proteases and act largely as a result of the neutralisation of these proteases by antibodies that are ingested with the blood-meal. In this review, we survey the current status of helminth proteases that show promise as vaccines and describe their vital contribution to a parasitic existence.
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Solano-Parada J, Gonzalez-Gonzalez G, Torró LMDP, dos Santos MFB, Espino AM, Burgos M, Osuna A. Effectiveness of intranasal vaccination against Angiostrongylus costaricensis using a serine/threonine phosphatase 2 A synthetic peptide and recombinant antigens. Vaccine 2010; 28:5185-96. [PMID: 20558243 DOI: 10.1016/j.vaccine.2010.05.072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 05/20/2010] [Accepted: 05/28/2010] [Indexed: 01/26/2023]
Abstract
Intranasal immunization was assayed in C57BL/6 mice against Angiostrongylus costaricensis using a synthetic and a recombinant peptide belonging to the catalytic region of the serine/threonine phosphatase 2 A (PP2A) of the parasite. Immunization was carried out with the synthetic peptide (SP) polymerized either with itself or with the beta fraction of the cholera toxin (CTB) and then enclosed in nanocapsules of phosphatidyl choline, cholesterol and Quil A (ISCOM). Another group of mice was immunized with recombinant peptide. Immunization consisted of two intranasal inoculations at two-week intervals, and the challenge with L3 larvae was made one month after the last vaccination. The effectiveness of immunization was evaluated 30 days after infection by analysis of the number of parasites in the arteries of the immunized mice, as well as by measuring spleen sizes in the experimental groups. The response induced was determined by identifying the isotypes of IgG as well as the IgE and IgA specific antigen response. The interleukins produced by the splenocyte culture of the different groups were assessed after exposing them to the peptide used in the immunization. From our results, 60%, 80%, and 100% protection against the A. costaricensis challenge was achieved in mice immunized with polymerized synthetic peptide in ISCOM, synthetic peptide polymerized with the CTB in ISCOM and inclusion bodies respectively. Splenomegaly was found to be less evident in the immunized mice than in the controls. A significant increase in IFN gamma and IL-17 levels was observed in the group with 100% protection. The results showed that vaccination through the nasal mucosa may constitute a useful method of immunization and result in a protective immune response against A. costaricensis.
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Affiliation(s)
- J Solano-Parada
- Institute of Biotechnology, Biochemistry and Molecular Parasitology Group, University of Granada, Edif Mecenas, Campus Fuentenueva, 18071 Granada, Spain
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Knopp S, Mohammed KA, Stothard JR, Khamis IS, Rollinson D, Marti H, Utzinger J. Patterns and risk factors of helminthiasis and anemia in a rural and a peri-urban community in Zanzibar, in the context of helminth control programs. PLoS Negl Trop Dis 2010; 4:e681. [PMID: 20485491 PMCID: PMC2867941 DOI: 10.1371/journal.pntd.0000681] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 03/25/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The control of helminth infections and prevention of anemia in developing countries are of considerable public health importance. The purpose of this study was to determine patterns and risk factors of helminth infections and anemia in a rural and a peri-urban community of Zanzibar, Tanzania, in the context of national helminth control programs. METHODOLOGY/PRINCIPAL FINDINGS We carried out a community-based cross-sectional study in 454 individuals by examining at least two stool samples with different methods for soil-transmitted helminths (Ascaris lumbricoides, hookworm, Strongyloides stercoralis, and Trichuris trichiura) and one urine sample for Schistosoma haematobium. Finger-prick blood was taken to estimate anemia levels and to detect antibody reactions against ascariasis, strongyloidiasis and schistosomiasis, using an enzyme-linked immunosorbent assay (ELISA) approach. Parasitological methods determined a helminth prevalence of 73.7% in the rural, and 48.9% in the peri-urban setting. Most helminth infections were of light intensity with school-aged children showing the highest intensities. Multiple helminth species infections were pervasive in rural dwellers regardless of age. More than half of the participants were anemic, with a particularly high prevalence in the peri-urban setting (64.7%). Risk factors for helminth infections were age, sex, consumption of raw vegetables or salad, recent travel history, and socio-economic status. CONCLUSION/SIGNIFICANCE After several years of chemotherapy-based morbidity control efforts in Zanzibar, helminth prevalences are still high and anemia is common, but helminth infection intensities are low. Hence, chemotherapy should be continued, and complemented with improved access to clean water, adequate sanitation, and health education, along with poverty alleviation measures for a more enduring impact.
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Affiliation(s)
- Stefanie Knopp
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Khalfan A. Mohammed
- Helminth Control Laboratory Unguja, Ministry of Health and Social Welfare, Zanzibar, Tanzania
| | - J. Russell Stothard
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, London, United Kingdom
| | - I. Simba Khamis
- Helminth Control Laboratory Unguja, Ministry of Health and Social Welfare, Zanzibar, Tanzania
| | - David Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, London, United Kingdom
| | - Hanspeter Marti
- Department of Medical and Diagnostic Services, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
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Wang Y, Xiao SH, Xue J, Singer BH, Utzinger J, Holmes E. Systems metabolic effects of a necator americanus infection in Syrian hamster. J Proteome Res 2010; 8:5442-50. [PMID: 19810771 DOI: 10.1021/pr900711j] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hookworms (Ancylostoma duodenale and Necator americanus) are blood-feeding intestinal nematodes that infect approximately 700 million people worldwide. To further our understanding of the systems metabolic response of the mammalian host to hookworm infection, we employed a metabolic profiling strategy involving the combination of (1)H NMR spectroscopic analysis of urine and serum and multivariate data analysis techniques to investigate the biochemical consequences of a N. americanus infection in the hamster. The infection was characterized by altered energy metabolism, consistent with hookworm-induced anemia. Additionally, disturbance of gut microbiotal activity was associated with a N. americanus infection, manifested in the alterations of microbial-mammalian cometabolites, including phenylacetylglycine, p-cresol glucuronide, 4-hydroxy-3-methyl-phenylpropionic acid, hippurate, 4-hydroxyphenylactate, and dimethylamine. The correlation between worm burden and metabolite concentrations also reflected a changed energy metabolism and gut microbial state. Furthermore, elevated levels of urinary 2-aminoadipate was a characteristic feature of the infection, which may be associated with the documented neurological consequences of hookworm infection.
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Affiliation(s)
- Yulan Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
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46
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Harhay MO, Horton J, Olliaro PL. Epidemiology and control of human gastrointestinal parasites in children. Expert Rev Anti Infect Ther 2010; 8:219-34. [PMID: 20109051 PMCID: PMC2851163 DOI: 10.1586/eri.09.119] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Parasites found in the human gastrointestinal tract can be largely categorized into two groups, protozoa and helminths. The soil-transmitted helminths (Ascaris lumbricoides, hookworm and Trichuris trichiura) are the most prevalent, infecting an estimated one-sixth of the global population. Infection rates are highest in children living in sub-Saharan Africa, followed by Asia and then Latin America and the Caribbean. The current momentum towards global drug delivery for their control is at a historical high through the efforts of numerous initiatives increasingly acting in coordination with donors, governments and local communities. Together, they have delivered enormous quantities of drugs, especially anthelmintics to children through nationwide annual or biannual mass drug administration largely coordinated through schools. However, a much larger and rapidly growing childhood population in these regions remains untreated and suffering from more than one parasite. Mass drug administration has profound potential for control but is not without considerable challenges and concerns. A principal barrier is funding. Stimulating a research and development pipeline, supporting the necessary clinical trials to refine treatment, in addition to procuring and deploying drugs (and sustaining these supply chains), requires substantial funding and resources that do not presently exist. Limited options for chemotherapy raise concerns about drug resistance developing through overuse, however, satisfactory pharmaco-epidemiology and monitoring for drug resistance requires more developed health infrastructures than are generally available. Further, the limited pharmacopeia does not include any effective second-line options if resistance emerges, and the research and development pipeline is severely depressed. Herein, we discuss the major gastrointestinal protozoa and helminths reviewing their impact on child health, changing epidemiology and how this relates to their control.
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Affiliation(s)
- Michael O Harhay
- Graduate Group in Demography, Population Studies Center, University of Pennsylvania, 239 McNeil Building, 3718 Locust Walk, Philadelphia, PA 19104-16298, USA, Tel.: +1 215 898 6441, Fax: +1 215 898 2124,
| | - John Horton
- 24 The Paddock, Hitchin, SG4 9EF, UK, Tel.: +44 146 262 4081, Fax: +44 146 264 8693,
| | - Piero L Olliaro
- Centre for Tropical Medicine, University of Oxford & United Nations Children’s Fund/United Nations Development Programme/World Bank/World Health Organization, Special Programme for Research and Training in Tropical Diseases (TDR), 20 Avenue Appia, CH-1211, Geneva 27, Switzerland, Tel.: +41 227 913 734, Fax: +41 227 914 774,
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Immunization with SmIg, a novel tegument protein fromSchistosoma mansoni, fails to induce protection in mice but reduces liver pathology. Parasitology 2009; 137:1079-88. [DOI: 10.1017/s0031182009991387] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
SUMMARYProteins associated with the schistosome tegument are of great importance for the development of new intervention strategies since they may be exposed on the surface of the parasite. Herein, we have isolated a cDNA clone encoding for theSchistosoma mansoniSmIg and its recombinant protein was tested as a potential vaccine candidate. Initially, its amino acid sequence was analysed by bioinformatics and shown to possess an N-terminal signal peptide, a C-terminal transmembrane helix, 4 glycosylation sites, an immunoglobulin conserved domain and 73% similarity with a hypotheticalS. japonicumprotein of unknown function. SmIg was produced byE. colias a recombinant protein (rSmIg) and its protective effectiveness was evaluated againstS. mansoniinfection with 100 cercariae in a murine model. Mice immunized with rSmIg induced an immune response characterized by dominant IgG1 isotype and significant levels of IFN-γ, TNF-α, IL-10 and IL-4. Although immunogenic, the recombinant vaccine failed to induce worm burden reduction when compared to the infected control group. However, rSmIg-immunized mice had significant reductions of liver granuloma volume and fibrosis content by 31·8% and 49%, respectively. In conclusion, SmIg is a new tegument protein fromS. mansonithat plays an important role in reducing pathology induced by parasite infection.
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48
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Hotez PJ, Fenwick A. Schistosomiasis in Africa: an emerging tragedy in our new global health decade. PLoS Negl Trop Dis 2009; 3:e485. [PMID: 19787054 PMCID: PMC2746322 DOI: 10.1371/journal.pntd.0000485] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Peter J. Hotez
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, D. C., United States of America
- Sabin Vaccine Institute, Washington, D. C., United States of America
- * E-mail: (PJH); (AF)
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College London, London, United Kingdom
- * E-mail: (PJH); (AF)
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Hotez PJ, Kamath A. Neglected tropical diseases in sub-saharan Africa: review of their prevalence, distribution, and disease burden. PLoS Negl Trop Dis 2009; 3:e412. [PMID: 19707588 PMCID: PMC2727001 DOI: 10.1371/journal.pntd.0000412] [Citation(s) in RCA: 742] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The neglected tropical diseases (NTDs) are the most common conditions affecting the poorest 500 million people living in sub-Saharan Africa (SSA), and together produce a burden of disease that may be equivalent to up to one-half of SSA's malaria disease burden and more than double that caused by tuberculosis. Approximately 85% of the NTD disease burden results from helminth infections. Hookworm infection occurs in almost half of SSA's poorest people, including 40-50 million school-aged children and 7 million pregnant women in whom it is a leading cause of anemia. Schistosomiasis is the second most prevalent NTD after hookworm (192 million cases), accounting for 93% of the world's number of cases and possibly associated with increased horizontal transmission of HIV/AIDS. Lymphatic filariasis (46-51 million cases) and onchocerciasis (37 million cases) are also widespread in SSA, each disease representing a significant cause of disability and reduction in the region's agricultural productivity. There is a dearth of information on Africa's non-helminth NTDs. The protozoan infections, human African trypanosomiasis and visceral leishmaniasis, affect almost 100,000 people, primarily in areas of conflict in SSA where they cause high mortality, and where trachoma is the most prevalent bacterial NTD (30 million cases). However, there are little or no data on some very important protozoan infections, e.g., amebiasis and toxoplasmosis; bacterial infections, e.g., typhoid fever and non-typhoidal salmonellosis, the tick-borne bacterial zoonoses, and non-tuberculosis mycobaterial infections; and arboviral infections. Thus, the overall burden of Africa's NTDs may be severely underestimated. A full assessment is an important step for disease control priorities, particularly in Nigeria and the Democratic Republic of Congo, where the greatest number of NTDs may occur.
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Affiliation(s)
- Peter J. Hotez
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- Sabin Vaccine Institute, Washington, D.C., United States of America
- * E-mail: or (PJH)
| | - Aruna Kamath
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- Sabin Vaccine Institute, Washington, D.C., United States of America
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50
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Affiliation(s)
- Peter J. Hotez
- Sabin Vaccine Institute, Washington, D.C., United States of America
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- * E-mail: or (PJH); (AF); (EFK)
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College London, London, United Kingdom
- * E-mail: or (PJH); (AF); (EFK)
| | - Eyrun F. Kjetland
- Centre for Imported and Tropical Diseases, Department of Infectious Diseases Ullevaal, Oslo University Hospital, Oslo, Norway
- University of Oslo, Oslo, Norway
- * E-mail: or (PJH); (AF); (EFK)
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