The Experts below are selected from a list of 678 Experts worldwide ranked by ideXlab platform
Peter J. Hotez - One of the best experts on this subject based on the ideXlab platform.
-
The Hookworm Ancylostoma ceylanicum intestinal transcriptome provides a platform for selecting drug and Vaccine candidates
Parasites & vectors, 2016Co-Authors: Junfei Wei, Maria Elena Bottazzi, Rojelio Mejia, Xin Gao, Ashish Damania, Zhuyun Liu, Makedonka Mitreva, Ulrich Strych, Peter J. HotezAbstract:The intestine of Hookworms contains enzymes and proteins involved in the blood-feeding process of the parasite and is therefore a promising source of possible Vaccine antigens. One such antigen, the hemoglobin-digesting intestinal aspartic protease known as Na-APR-1 from the human Hookworm Necator americanus, is currently a lead candidate antigen in clinical trials, as is Na-GST-1 a heme-detoxifying glutathione S-transferase. In order to discover additional Hookworm Vaccine antigens, messenger RNA was obtained from the intestine of male Hookworms, Ancylostoma ceylanicum, maintained in hamsters. RNA-seq was performed using Illumina high-throughput sequencing technology. The genes expressed in the Hookworm intestine were compared with those expressed in the whole worm and those genes overexpressed in the parasite intestine transcriptome were further analyzed. Among the lead transcripts identified were genes encoding for proteolytic enzymes including an A. ceylanicum APR-1, but the most common proteases were cysteine-, serine-, and metallo-proteases. Also in abundance were specific transporters of key breakdown metabolites, including amino acids, glucose, lipids, ions and water; detoxifying and heme-binding glutathione S-transferases; a family of cysteine-rich/antigen 5/pathogenesis-related 1 proteins (CAP) previously found in high abundance in parasitic nematodes; C-type lectins; and heat shock proteins. These candidates will be ranked for downstream antigen target selection based on key criteria including abundance, uniqueness in the parasite versus the vertebrate host, as well as solubility and yield of expression. The intestinal transcriptome of A. ceylanicum provides useful information for the identification of proteins involved in the blood-feeding process, representing a first step towards a reverse vaccinology approach to a human Hookworm Vaccine.
-
advancing a Vaccine to prevent Hookworm disease and anemia
Vaccine, 2016Co-Authors: Peter J. Hotez, Ulrich Strych, Coreen M Beaumier, Portia M Gillespie, Tara Hayward, Maria Elena BottazziAbstract:A human Hookworm Vaccine is under development and in clinical trials in Africa and the Americas. The Vaccine contains the Na-APR-1 and Na-GST-1 antigens. It elicits neutralizing antibodies that interfere with establishment of the adult Hookworm in the gut and the ability of the parasite to feed on blood. The Vaccine target product profile is focused on the immunization of children to prevent Hookworm infection and anemia caused by Necator americanus. It is intended for use in low- and middle-income countries where Hookworm is highly endemic and responsible for at least three million disability-adjusted life years. So far, the human Hookworm Vaccine is being developed in the non-profit sector through the Sabin Vaccine Institute Product Development Partnership (PDP), in collaboration with the HOOKVAC consortium of European and African partners. We envision the Vaccine to be incorporated into health systems as part of an elimination strategy for Hookworm infection and other neglected tropical diseases, and as a means to reduce global poverty and address the Sustainable Development Goals.
-
modeling the economic and epidemiologic impact of Hookworm Vaccine and mass drug administration mda in brazil a high transmission setting
Vaccine, 2016Co-Authors: Sarah M Bartsch, Jeffrey M Bethony, Peter J. Hotez, Maria Elena Bottazzi, David Diemert, Daniel L Hertenstein, Kristina M Zapf, Shawn T Brown, Bruce Y LeeAbstract: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.
-
optimization and revision of the production process of the necator americanus glutathione s transferase 1 na gst 1 the lead Hookworm Vaccine recombinant protein candidate
Human Vaccines & Immunotherapeutics, 2014Co-Authors: Elena Curti, Christopher A Seid, Elissa M Hudspeth, Wanderson C Rezende, Jeroen Pollet, Cliff Kwityn, Molly Hammond, Rise K Matsunami, David A Engler, Peter J. HotezAbstract:Infection by the human Hookworm Necator americanus is a leading cause of anemia and disability in the developing countries of Africa, Asia, and the Americas. In order to prevent childhood Hookworm disease in resource poor settings, a recombinant Vaccine is under development by the Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, a Product Development Partnership (PDP). Previously, we reported on the expression and purification of a highly promising Hookworm Vaccine candidate, Na-GST-1, an N. americanus glutathione s-transferase expressed in Pichia pastoris (yeast), which led to production of 1.5 g of 95% pure recombinant protein at a 20L scale. (1) (,) (2) (,) (3) This yield and purity of Na-GST-1 was sufficient for early pilot manufacturing and initial phase 1 clinical testing. However, based on the number of doses which would be required to allow mass vaccination and a potential goal to deliver a Vaccine as inexpensively as possible, a higher yield of expression of the recombinant antigen at the lowest possible cost is highly desirable. Here we report on modifications to the fermentation (upstream process) of the antigen expressed in P. pastoris, and to the purification (downstream process) of the recombinant protein that allowed for a 2-3-fold improvement in the final yield of Na-GST-1 purified protein. The major improvements included upstream process changes such as the addition of a sorbitol pulse and co-feed during methanol induction as well as an extension of the induction stage to approximately 96 hours; downstream process changes included modifying the UFDF to flat sheet with a 10 kDa Molecular Weight cut-off (MWCO), adjusting the capacity of an ion-exchange chromatography step utilizing a gradient elution as opposed to the original step elution, and altering the hydrophobic interaction chromatography conditions. The full process, as well as the purity and stability profiles of the target Na-GST-1, and its formulation on Alhydrogel(®), is described.
-
the human Hookworm Vaccine
Vaccine, 2013Co-Authors: Peter J. Hotez, Jeffrey M Bethony, Simon Brooker, Maria Elena Bottazzi, David Diemert, Kristina M Bacon, Coreen M Beaumier, Artur Roberto Couto, Marcos Da Silva Freire, Akira HommaAbstract:Hookworm infection is one of the world's most common neglected tropical diseases and a leading cause of iron deficiency anemia in low- and middle-income countries. A Human Hookworm Vaccine is currently being developed by the Sabin Vaccine Institute and is in phase 1 clinical testing. The candidate Vaccine is comprised of two recombinant antigens known as Na-GST-1 and Na-APR-1, each of which is an important parasite enzyme required for Hookworms to successfully utilize host blood as a source of energy. The recombinant proteins are formulated on Alhydrogel® and are being tested in combination with a synthetic Toll-like receptor 4 agonist. The aim of the Vaccine is to induce anti-enzyme antibodies that will reduce both host blood loss and the number of Hookworms attached to the gut. Transfer of the manufacturing technology to the Oswaldo Cruz Foundation (FIOCRUZ)/Bio-Manguinhos (a Brazilian public sector developing country Vaccine manufacturer) is planned, with a clinical development plan that could lead to registration of the Vaccine in Brazil. The Vaccine would also need to be introduced in the poorest regions of Africa and Asia, where Hookworm infection is highly endemic. Ultimately, the Vaccine could become an essential tool for achieving Hookworm control and elimination, a key target in the 2012 London Declaration on Neglected Tropical Diseases.
Vidadi Yusibov - One of the best experts on this subject based on the ideXlab platform.
-
expression purification and characterization of the necator americanus aspartic protease 1 na apr 1 m74 antigen a component of the bivalent human Hookworm Vaccine
Human Vaccines & Immunotherapeutics, 2015Co-Authors: Christopher A Seid, Elissa M Hudspeth, Wanderson C Rezende, Sonya Pritchard, Konstantin Musiychuk, Jeroen Pollet, Leroy Versteeg, Elena Curti, Mark R. Jones, Vidadi YusibovAbstract:Over 400 million people living in the world's poorest developing nations are infected with Hookworms, mostly of the genus Necator americanus. A bivalent human Hookworm Vaccine composed of the Necator americanus Glutathione S-Transferase-1 (Na-GST-1) and the Necator americanus Aspartic Protease-1 (Na-APR-1 (M74)) is currently under development by the Sabin Vaccine Institute Product Development Partnership (Sabin PDP). Both monovalent Vaccines are currently in Phase 1 trials. Both Na-GST-1 and Na-APR-1 antigens are expressed as recombinant proteins. While Na-GST-1 was found to express with high yields in Pichia pastoris, the level of expression of Na-APR-1 in this host was too low to be suitable for a manufacturing process. When the tobacco plant Nicotiana benthamiana was evaluated as an expression system, acceptable levels of solubility, yield, and stability were attained. Observed expression levels of Na-APR-1 (M74) using this system are ∼300 mg/kg. Here we describe the achievements and obstacles encounte...
-
expression purification and characterization of the necator americanus aspartic protease 1 na apr 1 m74 antigen a component of the bivalent human Hookworm Vaccine
Human Vaccines & Immunotherapeutics, 2015Co-Authors: Christopher A Seid, Elissa M Hudspeth, Wanderson C Rezende, Sonya Pritchard, Konstantin Musiychuk, Jeroen Pollet, Leroy Versteeg, Elena Curti, Mark R. Jones, Vidadi YusibovAbstract:Over 400 million people living in the world's poorest developing nations are infected with Hookworms, mostly of the genus Necator americanus. A bivalent human Hookworm Vaccine composed of the Necator americanus Glutathione S-Transferase-1 (Na-GST-1) and the Necator americanus Aspartic Protease-1 (Na-APR-1 (M74)) is currently under development by the Sabin Vaccine Institute Product Development Partnership (Sabin PDP). Both monovalent Vaccines are currently in Phase 1 trials. Both Na-GST-1 and Na-APR-1 antigens are expressed as recombinant proteins. While Na-GST-1 was found to express with high yields in Pichia pastoris, the level of expression of Na-APR-1 in this host was too low to be suitable for a manufacturing process. When the tobacco plant Nicotiana benthamiana was evaluated as an expression system, acceptable levels of solubility, yield, and stability were attained. Observed expression levels of Na-APR-1 (M74) using this system are ∼300 mg/kg. Here we describe the achievements and obstacles encountered during process development as well as characterization and stability of the purified Na-APR-1 (M74) protein and formulated Vaccine. The expression, purification and analysis of purified Na-APR-1 (M74) protein obtained from representative 5 kg reproducibility runs performed to qualify the Na-APR-1 (M74) production process is also presented. This process has been successfully transferred to a pilot plant and a 50 kg scale manufacturing campaign under current Good Manufacturing Practice (cGMP) has been performed. The 50 kg run has provided a sufficient amount of protein to support the ongoing Hookworm Vaccine development program of the Sabin PDP.
Christopher A Seid - One of the best experts on this subject based on the ideXlab platform.
-
expression purification and characterization of the necator americanus aspartic protease 1 na apr 1 m74 antigen a component of the bivalent human Hookworm Vaccine
Human Vaccines & Immunotherapeutics, 2015Co-Authors: Christopher A Seid, Elissa M Hudspeth, Wanderson C Rezende, Sonya Pritchard, Konstantin Musiychuk, Jeroen Pollet, Leroy Versteeg, Elena Curti, Mark R. Jones, Vidadi YusibovAbstract:Over 400 million people living in the world's poorest developing nations are infected with Hookworms, mostly of the genus Necator americanus. A bivalent human Hookworm Vaccine composed of the Necator americanus Glutathione S-Transferase-1 (Na-GST-1) and the Necator americanus Aspartic Protease-1 (Na-APR-1 (M74)) is currently under development by the Sabin Vaccine Institute Product Development Partnership (Sabin PDP). Both monovalent Vaccines are currently in Phase 1 trials. Both Na-GST-1 and Na-APR-1 antigens are expressed as recombinant proteins. While Na-GST-1 was found to express with high yields in Pichia pastoris, the level of expression of Na-APR-1 in this host was too low to be suitable for a manufacturing process. When the tobacco plant Nicotiana benthamiana was evaluated as an expression system, acceptable levels of solubility, yield, and stability were attained. Observed expression levels of Na-APR-1 (M74) using this system are ∼300 mg/kg. Here we describe the achievements and obstacles encounte...
-
expression purification and characterization of the necator americanus aspartic protease 1 na apr 1 m74 antigen a component of the bivalent human Hookworm Vaccine
Human Vaccines & Immunotherapeutics, 2015Co-Authors: Christopher A Seid, Elissa M Hudspeth, Wanderson C Rezende, Sonya Pritchard, Konstantin Musiychuk, Jeroen Pollet, Leroy Versteeg, Elena Curti, Mark R. Jones, Vidadi YusibovAbstract:Over 400 million people living in the world's poorest developing nations are infected with Hookworms, mostly of the genus Necator americanus. A bivalent human Hookworm Vaccine composed of the Necator americanus Glutathione S-Transferase-1 (Na-GST-1) and the Necator americanus Aspartic Protease-1 (Na-APR-1 (M74)) is currently under development by the Sabin Vaccine Institute Product Development Partnership (Sabin PDP). Both monovalent Vaccines are currently in Phase 1 trials. Both Na-GST-1 and Na-APR-1 antigens are expressed as recombinant proteins. While Na-GST-1 was found to express with high yields in Pichia pastoris, the level of expression of Na-APR-1 in this host was too low to be suitable for a manufacturing process. When the tobacco plant Nicotiana benthamiana was evaluated as an expression system, acceptable levels of solubility, yield, and stability were attained. Observed expression levels of Na-APR-1 (M74) using this system are ∼300 mg/kg. Here we describe the achievements and obstacles encountered during process development as well as characterization and stability of the purified Na-APR-1 (M74) protein and formulated Vaccine. The expression, purification and analysis of purified Na-APR-1 (M74) protein obtained from representative 5 kg reproducibility runs performed to qualify the Na-APR-1 (M74) production process is also presented. This process has been successfully transferred to a pilot plant and a 50 kg scale manufacturing campaign under current Good Manufacturing Practice (cGMP) has been performed. The 50 kg run has provided a sufficient amount of protein to support the ongoing Hookworm Vaccine development program of the Sabin PDP.
-
optimization and revision of the production process of the necator americanus glutathione s transferase 1 na gst 1 the lead Hookworm Vaccine recombinant protein candidate
Human Vaccines & Immunotherapeutics, 2014Co-Authors: Elena Curti, Christopher A Seid, Elissa M Hudspeth, Wanderson C Rezende, Jeroen Pollet, Cliff Kwityn, Molly Hammond, Rise K Matsunami, David A Engler, Peter J. HotezAbstract:Infection by the human Hookworm Necator americanus is a leading cause of anemia and disability in the developing countries of Africa, Asia, and the Americas. In order to prevent childhood Hookworm disease in resource poor settings, a recombinant Vaccine is under development by the Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, a Product Development Partnership (PDP). Previously, we reported on the expression and purification of a highly promising Hookworm Vaccine candidate, Na-GST-1, an N. americanus glutathione s-transferase expressed in Pichia pastoris (yeast), which led to production of 1.5 g of 95% pure recombinant protein at a 20L scale. (1) (,) (2) (,) (3) This yield and purity of Na-GST-1 was sufficient for early pilot manufacturing and initial phase 1 clinical testing. However, based on the number of doses which would be required to allow mass vaccination and a potential goal to deliver a Vaccine as inexpensively as possible, a higher yield of expression of the recombinant antigen at the lowest possible cost is highly desirable. Here we report on modifications to the fermentation (upstream process) of the antigen expressed in P. pastoris, and to the purification (downstream process) of the recombinant protein that allowed for a 2-3-fold improvement in the final yield of Na-GST-1 purified protein. The major improvements included upstream process changes such as the addition of a sorbitol pulse and co-feed during methanol induction as well as an extension of the induction stage to approximately 96 hours; downstream process changes included modifying the UFDF to flat sheet with a 10 kDa Molecular Weight cut-off (MWCO), adjusting the capacity of an ion-exchange chromatography step utilizing a gradient elution as opposed to the original step elution, and altering the hydrophobic interaction chromatography conditions. The full process, as well as the purity and stability profiles of the target Na-GST-1, and its formulation on Alhydrogel(®), is described.
Hotez, Peter J. - One of the best experts on this subject based on the ideXlab platform.
-
Hookworm infection
Health Sciences Research Commons, 2016Co-Authors: Loukas Alex, Hotez, Peter J., Diemert David, Correa-oliveira Rodrigo, Yazdanbakhsh Maria, Mccarthy, James S., Croese John, Bethony, Jeffrey M.Abstract:© 2016 Macmillan Publishers Limited, part of Springer Nature. 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 \u3e4 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\u27s 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
-
Modeling the economic and epidemiologic impact of Hookworm Vaccine and mass drug administration (MDA) in Brazil, a high transmission setting
Health Sciences Research Commons, 2016Co-Authors: Bartsch, Sarah M., Diemert, David J., Hotez, Peter J., Bethony, Jeffrey M., Bottazzi, Maria Elena, Hertenstein, Daniel L., Zapf, Kristina M., Brown, Shawn T., Lee, Bruce Y.Abstract:© 2016 Elsevier Ltd. 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\u27s 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
-
New tools for NTD Vaccines: a case study of quality control assays for product development of the human Hookworm Vaccine Na-APR-1M74
Landes Bioscience, 2015Co-Authors: Pearson, Mark S., Jariwala, Amar R., Hotez, Peter J., Bethony, Jeffrey M., Bottazzi, Maria Elena, Abbenante Giovanni, Plieskatt Jordan, Wilson David, Keegan Brian, Loukas AlexAbstract:Na-APR-1M74 is an aspartic protease that is rendered enzymatically inactive by site-directed mutagenesis and is a candidate antigen component in the Human Hookworm Vaccine. The mutant protease exerts Vaccine efficacy by inducing antibodies that neutralize the enzymatic activity of wild type enzyme (Na-APR-1wt) in the gut of the Hookworm, thereby depriving the worm of its ability to digest its blood meal. Previously, canines immunized with Na-APR-1M74 and challenged with Ancylostoma caninum were partially protected against Hookworm challenge infection, especially from the loss in hemoglobin observed in control canines and canine immunoglobulin (Ig) G raised against Na-APR-1 was shown to inhibit the enzymatic activity of Na-APR-1wt in vitro, thereby providing proof of concept of Na-APR-1M74 as a Vaccine antigen. The mutated version, Na-APR-1M74, was then expressed at the cGMP level using a Nicotiana benthamiana expression system (Fraunhofer, CMB, Delaware, MD), formulated with Alhydrogel®, and used to immunize mice in a dose-ranging study to explore the enzyme-neutralizing capacity of the resulting anti- Na-APR-1M74 IgG. As little as 0.99 μg of recombinant Na-APR-1M74 could induce anti Na-APR-1M74 IgG in mice that were capable of inhibiting Na-APR-1wt-mediated digestion of a peptide substrate by 89%. In the absence of enzymatic activity of Na-APR-1M74 as a surrogate marker of protein functionality, we developed an assay based on the binding of a quenched fluorescence-labeled inhibitor of aspartic proteases, BODIPY-FL pepstatin A (BDP). Binding of BDP in the active site of Na-APR-1wt was demonstrated by inhibition of enzymatic activity, and competitive binding with unlabelled pepstatin A. BDP also bound to Na-APR-1M74 which was assessed by fluorescence polarization, but with an ~50-fold reduction in the dissociation constant. Taken together, these assays comprise a "toolbox" that could be useful for the analyses of Na-APR-1M74 as it proceeds through the clinical development as part of the Human Hookworm Vaccine pipeline
-
Vaccination with Human Hookworm Vaccine Necator americanus Aspartic Protease-1 M74 Generates Neutralizing Antibodies and a Potent Immune Response in BALB/c Mice
Health Sciences Research Commons, 2013Co-Authors: Jariwala, Amar R., Hotez, Peter J., Brelsford, Jill B., Plieskatt, Jordan L., Pearson, Mark S., Keegan Brian, Loukas Alex, Xi Chen, Zhan Bin, Bethony, Jeffrey M.Abstract:Backgound: Human Hookworm Infection, a neglected tropical disease infects more than 600 million people around the world. Hookworms ingest hemoglobin containing erythrocytes and Necator americanus Aspartic Protease-1 wild type (Na-APR-1wt) a hemoglobinase cleaves hemoglobin to form Heme and Globin. Globin is further digested by other gut enzymes and the nutritional end products are absorbed by the Hookworm’s gut wall. Also, Heme which is toxic to Hookworm is detoxified by the Necator americanus Glutathione Transferase-1 (Na-GST-1) a detoxification enzyme secreted by the gut of the Hookworm. Necator americanus Aspartic Protease-1 M74 (Na-APR-1 M74) is the new Vaccine for the Human Hookworm Infection which is currently under pre-clinical development. Na-APR-1 M74 Vaccine is an Alhydrogel® adjuvanted Vaccine containing the mutant form of the Na-APR-1wt. Neutralizing Na-APR-1wt by potent antibodies (IgG) in the Vaccinees will block the initiation of the hemoglobin digestion cascade and starve the Hookworms from essential nutrition, leading to their death. Here, we report the results of the neutralizing capacity of antibodies and potency (immunogenicity) of Na-APR-1 M74 Vaccine in BALB/c mice. Methods: Serum for IgG was generated by vaccinating BALB/c mice twice subcutaneously with Na-APR-1 M74 an enzymatically inactive mutant form of Na-APR-1wt formulated with Alhydrogel®. Assessment of neutralizing capacity of IgG was performed using the standard Cathepsin-D protease assay using MOCAc substrate. Dose response (% Inhibition vs Dose) was assessed using linear regression analysis. Potency testing of the Na-APR-1M74 clinical drug product was performed by standard bioassay. Median Effective Dose 50 (ED50) with the 95% fiducial limits (95%FL) was estimated using Probit Analysis (SAS® 9.3). Also, Relative Potency (RP) was estimated by the methods described in European Pharmacopeia\u27s Chapter 5.3. Results: Five microgram of IgG neutralized 51.06% of the enzymatic activity of 250ng of Na-APR-1wt. An excellent dose response was also observed. ED50 of 14.15μg (95%FL = 10.47μg -- 18.93μg) and 11.46μg (95%FL = 4.86μg --27.42μg) was estimated for time 1 and 7 month post manufacture respectively. RP at 7 months was found to be 1.23 (95%FL = 0.792--1.917). Conclusion: These preclinical results of the Na-APR-1 M74 Vaccine lay the foundation for a Phase 1 Clinical Trial in USA and Brazil. This Na-APR-1 M74 Vaccine will be subsequently combined with Necator americanus Glutathione transferase-1 (Na-GST-1) Vaccine to form a multivalent human Hookworm Vaccine
-
The human Hookworm Vaccine
Health Sciences Research Commons, 2013Co-Authors: Hotez, Peter J., Bethony, Jeffrey M., Diemert David, Bacon, Kristina M., Beaumier Coreen, Bottazzi, Maria Elena, Brooker Simon, Couto, Artur Roberto, Da Silva Freire Marcos, Homma AkiraAbstract:Hookworm infection is one of the world\u27s most common neglected tropical diseases and a leading cause of iron deficiency anemia in low- and middle-income countries. A Human Hookworm Vaccine is currently being developed by the Sabin Vaccine Institute and is in phase 1 clinical testing. The candidate Vaccine is comprised of two recombinant antigens known as Na-GST-1 and Na-APR-1, each of which is an important parasite enzyme required for Hookworms to successfully utilize host blood as a source of energy. The recombinant proteins are formulated on Alhydrogel® and are being tested in combination with a synthetic Toll-like receptor 4 agonist. The aim of the Vaccine is to induce anti-enzyme antibodies that will reduce both host blood loss and the number of Hookworms attached to the gut. Transfer of the manufacturing technology to the Oswaldo Cruz Foundation (FIOCRUZ)/Bio-Manguinhos (a Brazilian public sector developing country Vaccine manufacturer) is planned, with a clinical development plan that could lead to registration of the Vaccine in Brazil. The Vaccine would also need to be introduced in the poorest regions of Africa and Asia, where Hookworm infection is highly endemic. Ultimately, the Vaccine could become an essential tool for achieving Hookworm control and elimination, a key target in the 2012 London Declaration on Neglected Tropical Diseases. © 2012 Elsevier Ltd
Alex Loukas - One of the best experts on this subject based on the ideXlab platform.
-
Oral Peptide Vaccine against Hookworm Infection: Correlation of Antibody Titers with Protective Efficacy
'MDPI AG', 2021Co-Authors: Ahmed O. Shalash, Alex Loukas, Mariusz Skwarczynski, Luke Becker, Jieru Yang, Paul Giacomin, Mark Pearson, Waleed M. Hussein, Istvan TothAbstract:Approximately 0.4 billion individuals worldwide are infected with Hookworm. An effective Vaccine is needed to not only improve the health of those affected and at high risk, but also to improve economic growth in disease-endemic areas. An ideal anti-Hookworm therapeutic strategy for mass administration is a stable and orally administered Vaccine. Oral Vaccines are advantageous as they negate the need for trained medical staff for administration and do not require strict sterility conditions. Vaccination, therefore, can be carried out at a significantly reduced cost. One of the most promising current antigenic targets for Hookworm Vaccine development is the aspartic protease digestive enzyme (APR-1). Antibody-mediated neutralization of APR-1 deprives the worm of nourishment, leading to reduced worm burdens in vaccinated hosts. Previously, we demonstrated that, when incorporated into Vaccine delivery systems, the APR-1-derived p3 epitope (TSLIAGPKAQVEAIQKYIGAEL) was able to greatly reduce worm burdens (≥90%) in BALB/c mice; however, multiple, large doses of the Vaccine were required. Here, we investigated a variety of p3-antigen conjugates to optimize antigen delivery and establish immune response/protective efficacy relationships. We synthesized, purified, and characterized four p3 peptide-based Vaccine candidates with: (a) lipidic (lipid core peptide (LCP)); (b) classical polymeric (polymethylacrylate (PMA)); and (c) novel polymeric (polyleucine in a branched or linear arrangement, BL10 or LL10, respectively) groups as self-adjuvanting moieties. BL10 and LL10 induced the highest serum anti-p3 and anti-APR-1 IgG titers. Upon challenge with rodent Hookworms, the highest significant reduction in worm burden was observed in mice immunized with LL10. APR-1-specific serum IgG titers correlated with worm burden reduction. Thus, we provide the first Vaccine-triggered immune response-protection relationship for Hookworm infection
-
Hookworm infection.
Nature reviews. Disease primers, 2016Co-Authors: Alex Loukas, James S. Mccarthy, David Diemert, Maria Yazdanbakhsh, Rodrigo Correa-oliveiraAbstract: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.
-
generalized urticaria induced by the na asp 2 Hookworm Vaccine implications for the development of Vaccines against helminths
The Journal of Allergy and Clinical Immunology, 2012Co-Authors: David Diemert, Amar R. Jariwala, Maria Victoria Periago, Janaína Freire, Helton C Santiago, Antonio Gomes Pinto, Robert G Hamilton, Alex LoukasAbstract:Objective: To assess the safety and immunogenicity of recombinant Na-ASP-2 adjuvanted with Alhydrogel in healthy Brazilian adults previously infected with N americanus. Methods: Participants were randomized to receive Na-ASP-2 or hepatitis B Vaccine. Major IgG and IgE epitopes of the Na-ASP-2 molecule were mapped by using sera from these same subjects. Seroepidemiologic studies in adults and children residing in Hookworm-endemic areas were conducted to assess the prevalence of IgE responses to Na-ASP-2. Results; Vaccination with a single dose of Na-ASP-2 resulted in generalized urticarial reactions in several volunteers. These reactions were associated with pre-existing Na-ASP-2–specific IgE likely induced by previous Hookworm infection. Surveys revealed that a significant proportion of the population in Hookworm-endemic areas had increased levels of IgE to Na-ASP-2. Epitope mapping demonstrated sites on the Na-ASP-2 molecule that are uniquely or jointly recognized by IgG and IgE antibodies. Conclusion: Infection with N americanus induces increased levels of total and specific IgE to Na-ASP-2 that result in generalized urticaria on vaccination with recombinant Na-ASP-2. These data advance knowledge of Vaccine development for helminths given their propensity to induce strong TH2 responses. Study data highlight the important differences between the immune responses to natural helminth infection and to vaccination with a recombinant helminth antigen.
-
Hookworm Vaccines past present and future
Lancet Infectious Diseases, 2006Co-Authors: Alex Loukas, Jeffrey M Bethony, Simon Brooker, Peter J. HotezAbstract:Hookworms are gastrointestinal nematodes that infect almost 1 billion people in developing countries. The main clinical symptom of human Hookworm infections is iron-deficiency anaemia, a direct consequence of the intestinal blood loss resulting from the parasite's feeding behaviour. Although treatment is available and currently used for the periodic removal of adult Hookworms from patients, this approach has not effectively controlled Hookworm in areas of rural poverty. Furthermore, treated individuals remain susceptible to reinfection following exposure to third-stage infective Hookworm larvae in the soil as early as 4-12 months after drug treatment. Therefore, a prophylactic Vaccine against Hookworm infection would provide an attractive additional tool for the public-health control of this disease. The feasibility of developing a Vaccine is based on the previous success of an attenuated larval Vaccine against canine Hookworm. Several laboratory and field studies have explored the development of a human anti-Hookworm Vaccine, describing potential protective mechanisms and identifying candidate antigens, one of which is now in clinical trials. The current roadmap that investigators have conceived has been influenced by Vaccine development for blood-feeding nematodes of livestock and companion animals; however, recombinant Vaccines have yet to be developed for nematodes that parasitise animals or human beings. The roadmap also addresses the obstacles facing development of a Vaccine for developing countries, where there is no commercial market.
-
New technologies for the control of human Hookworm infection
Trends in parasitology, 2006Co-Authors: Peter J. Hotez, Jeffrey M Bethony, Simon Brooker, Maria Elena Bottazzi, David Diemert, Alex LoukasAbstract:Since the 1990s, the major approach to Hookworm control has been morbidity reduction in school-aged children by periodic deworming with benzimidazoles. Now, efforts are underway to determine the feasibility of integrating deworming with control programs that target other neglected tropical diseases. However, the sustainability of benzimidazole deworming for Hookworm is of concern because of the variable efficacy of mebendazole, high rates of post-treatment reinfection and possible development of drug resistance. This requires parallel efforts to develop new and complementary Hookworm control tools, such as new anthelmintic drugs (e.g. tribendimidine) and a recombinant Hookworm Vaccine. It is hoped that, ultimately, anthelmintic vaccination will be linked to deworming as part of an expanded control package.