101
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Virus-Like Particle Vaccines Against Respiratory Viruses and Protozoan Parasites. Curr Top Microbiol Immunol 2021; 433:77-106. [PMID: 33650036 DOI: 10.1007/82_2021_232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The field of vaccinology underwent massive advances over the past decades with the introduction of virus-like particles (VLPs), a supra-molecular nanoparticle vaccine platform that resembles viral structures without the ability to replicate in hosts. This innovative approach has been remarkably effective, as evidenced by its profound immunogenicity and safety. These highly desirable intrinsic properties enabled their further development as vaccines against a multitude of diseases. To date, several VLP-based vaccines have already been commercialized and many more are undergoing clinical evaluation prior to FDA approval. However, efficacious vaccines against a plethora of pathogens are still lacking, which imposes a tremendous socioeconomic burden and continues to threaten public health throughout the globe. This is especially the case for several respiratory pathogens and protozoan parasites. In this review, we briefly describe the fundamentals of VLP vaccines and the unique properties that enable these to be such valuable vaccine candidates and summarize current advances in VLP-based vaccines targeting respiratory and parasitic diseases of global importance.
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102
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Abstract
Almost 20 years have passed since the first reference genome assemblies were published for Plasmodium falciparum, the deadliest malaria parasite, and Anopheles gambiae, the most important mosquito vector of malaria in sub-Saharan Africa. Reference genomes now exist for all human malaria parasites and nearly half of the ~40 important vectors around the world. As a foundation for genetic diversity studies, these reference genomes have helped advance our understanding of basic disease biology and drug and insecticide resistance, and have informed vaccine development efforts. Population genomic data are increasingly being used to guide our understanding of malaria epidemiology, for example by assessing connectivity between populations and the efficacy of parasite and vector interventions. The potential value of these applications to malaria control strategies, together with the increasing diversity of genomic data types and contexts in which data are being generated, raise both opportunities and challenges in the field. This Review discusses advances in malaria genomics and explores how population genomic data could be harnessed to further support global disease control efforts.
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Affiliation(s)
- Daniel E Neafsey
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, USA.
| | - Aimee R Taylor
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Bronwyn L MacInnis
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, USA.
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103
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Kolli SK, Salman AM, Ramesar J, Chevalley-Maurel S, Kroeze H, Geurten FGA, Miyazaki S, Mukhopadhyay E, Marin-Mogollon C, Franke-Fayard B, Hill AVS, Janse CJ. Screening of viral-vectored P. falciparum pre-erythrocytic candidate vaccine antigens using chimeric rodent parasites. PLoS One 2021; 16:e0254498. [PMID: 34252120 PMCID: PMC8274855 DOI: 10.1371/journal.pone.0254498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/28/2021] [Indexed: 11/19/2022] Open
Abstract
To screen for additional vaccine candidate antigens of Plasmodium pre-erythrocytic stages, fourteen P. falciparum proteins were selected based on expression in sporozoites or their role in establishment of hepatocyte infection. For preclinical evaluation of immunogenicity of these proteins in mice, chimeric P. berghei sporozoites were created that express the P. falciparum proteins in sporozoites as an additional copy gene under control of the uis4 gene promoter. All fourteen chimeric parasites produced sporozoites but sporozoites of eight lines failed to establish a liver infection, indicating a negative impact of these P. falciparum proteins on sporozoite infectivity. Immunogenicity of the other six proteins (SPELD, ETRAMP10.3, SIAP2, SPATR, HT, RPL3) was analyzed by immunization of inbred BALB/c and outbred CD-1 mice with viral-vectored (ChAd63 or ChAdOx1, MVA) vaccines, followed by challenge with chimeric sporozoites. Protective immunogenicity was determined by analyzing parasite liver load and prepatent period of blood stage infection after challenge. Of the six proteins only SPELD immunized mice showed partial protection. We discuss both the low protective immunogenicity of these proteins in the chimeric rodent malaria challenge model and the negative effect on P. berghei sporozoite infectivity of several P. falciparum proteins expressed in the chimeric sporozoites.
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Affiliation(s)
- Surendra Kumar Kolli
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Ahmed M. Salman
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jai Ramesar
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Hans Kroeze
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Fiona G. A. Geurten
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Shinya Miyazaki
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Ekta Mukhopadhyay
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Adrian V. S. Hill
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Chris J. Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
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104
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Blight J, Sala KA, Atcheson E, Kramer H, El-Turabi A, Real E, Dahalan FA, Bettencourt P, Dickinson-Craig E, Alves E, Salman AM, Janse CJ, Ashcroft FM, Hill AV, Reyes-Sandoval A, Blagborough AM, Baum J. Dissection-independent production of Plasmodium sporozoites from whole mosquitoes. Life Sci Alliance 2021; 4:e202101094. [PMID: 34135099 PMCID: PMC8321652 DOI: 10.26508/lsa.202101094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 01/05/2023] Open
Abstract
Progress towards a protective vaccine against malaria remains slow. To date, only limited protection has been routinely achieved following immunisation with either whole-parasite (sporozoite) or subunit-based vaccines. One major roadblock to vaccine progress, and to pre-erythrocytic parasite biology in general, is the continued reliance on manual salivary gland dissection for sporozoite isolation from infected mosquitoes. Here, we report development of a multi-step method, based on batch processing of homogenised whole mosquitoes, slurry, and density-gradient filtration, which combined with free-flow electrophoresis rapidly produces a pure, infective sporozoite inoculum. Human-infective Plasmodium falciparum and rodent-infective Plasmodium berghei sporozoites produced in this way are two- to threefold more infective than salivary gland dissection sporozoites in in vitro hepatocyte infection assays. In an in vivo rodent malaria model, the same P. berghei sporozoites confer sterile protection from mosquito-bite challenge when immunisation is delivered intravenously or 60-70% protection when delivered intramuscularly. By improving purity, infectivity, and immunogenicity, this method represents a key advancement in capacity to produce research-grade sporozoites, which should impact delivery of a whole-parasite based malaria vaccine at scale in the future.
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Affiliation(s)
- Joshua Blight
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Katarzyna A Sala
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
| | - Erwan Atcheson
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Holger Kramer
- Department of Physiology, Anatomy and Genetics, Henry Wellcome Building for Gene Function, University of Oxford, Oxford, UK
- Medical Research Council London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Aadil El-Turabi
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Eliana Real
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
| | - Farah A Dahalan
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
| | - Paulo Bettencourt
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Emma Dickinson-Craig
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Eduardo Alves
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Ahmed M Salman
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Chris J Janse
- Department of Parasitology, Leiden Malaria Research Group, Center of Infectious Diseases, Leiden University Medical Center, (LUMC, L4-Q), Leiden, The Netherlands
| | - Frances M Ashcroft
- Department of Physiology, Anatomy and Genetics, Henry Wellcome Building for Gene Function, University of Oxford, Oxford, UK
| | - Adrian Vs Hill
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Arturo Reyes-Sandoval
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, UK
- Instituto Politécnico Nacional, Mexico City, Mexico
| | - Andrew M Blagborough
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, UK
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105
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Niu G, Cui Y, Wang X, Keleta Y, Li J. Studies of the Parasite-Midgut Interaction Reveal Plasmodium Proteins Important for Malaria Transmission to Mosquitoes. Front Cell Infect Microbiol 2021; 11:654216. [PMID: 34262880 PMCID: PMC8274421 DOI: 10.3389/fcimb.2021.654216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/10/2021] [Indexed: 11/16/2022] Open
Abstract
Malaria transmission relies on parasite-mosquito midgut interaction. The interactive proteins are hypothesized to be ideal targets to block malaria transmission to mosquitoes. We chose 76 genes that contain signal peptide-coding regions and are upregulated and highly abundant at sexual stages. Forty-six of these candidate genes (60%) were cloned and expressed using the baculovirus expression system in insect cells. Six of them, e.g., PF3D7_0303900, PF3D7_0406200 (Pfs16), PF3D7_1204400 (Pfs37), PF3D7_1214800, PF3D7_1239400, and PF3D7_1472800 were discovered to interact with blood-fed mosquito midgut lysate. Previous works showed that among these interactive proteins, knockout the orthologs of Pfs37 or Pfs16 in P. berghei reduced oocysts in mosquitoes. Here we further found that anti-Pfs16 polyclonal antibody significantly inhibited P. falciparum transmission to Anopheles gambiae. Investigating these candidate proteins will improve our understanding of malaria transmission and discover new targets to break malaria transmission.
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Affiliation(s)
| | | | | | | | - Jun Li
- Department of Biological Sciences, Biomolecular Sciences Institute, Florida International University, Miami, FL, United States
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106
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Arévalo-Herrera M, Miura K, Cespedes N, Echeverry C, Solano E, Castellanos A, Ramirez JS, Miranda A, Kajava AV, Long C, Corradin G, Herrera S. Immunoreactivity of Sera From Low to Moderate Malaria-Endemic Areas Against Plasmodium vivax r Pvs48/45 Proteins Produced in Escherichia coli and Chinese Hamster Ovary Systems. Front Immunol 2021; 12:634738. [PMID: 34248932 PMCID: PMC8264144 DOI: 10.3389/fimmu.2021.634738] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
P48/45 is a conserved gametocyte antigen involved in Plasmodium parasite fertilization. A recombinant Plasmodium vivax P48/45 (Pvs48/45) protein expressed in Escherichia coli (E. coli) was highly antigenic and immunogenic in experimental animals and elicited specific transmission-blocking (TB) antibodies in a previous pilot study. Here, a similar Pvs48/45 gene was expressed in Chinese Hamster Ovary (CHO) cells and we compared its immunoreactivity with the E. coli product. Specific antibody titers were determined using plasma from Colombian individuals (n=227) living in endemic areas where both P. vivax and P. falciparum are prevalent and from Guatemala (n=54) where P. vivax is highly prevalent. In Colombia, plasma seroprevalence to CHO-rPvs48/45 protein was 46.3%, while for E. coli-rPvs48/45 protein was 36.1% (p<0.001). In Guatemala, the sero prevalence was 24.1% and 14.8% (p<0.001), respectively. Reactivity index (RI) against both proteins showed an age-dependent increase. IgG2 was the predominant subclass and the antibody avidity index evaluated by ELISA ranged between 4-6 mol/L. Ex vivo P. vivax mosquito direct membrane feeding assays (DMFA) performed in presence of study plasmas, displayed significant parasite transmission-blocking (TB), however, there was no direct correlation between antibody titers and oocysts transmission reduction activity (%TRA). Nevertheless, DMFA with CHO rPvs48/45 affinity purified IgG showed a dose response; 90.2% TRA at 100 μg/mL and 71.8% inhibition at 10 μg/mL. In conclusion, the CHO-rPvs48/45 protein was more immunoreactive in most of the malaria endemic places studied, and CHO-rPvs48/45 specific IgG showed functional activity, supporting further testing of the protein vaccine potential.
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Affiliation(s)
- Myriam Arévalo-Herrera
- Immunology Department, Malaria Vaccine and Drug Development Center, Cali, Colombia
- Immunology Department, Caucaseco Scientific Research Center, Cali, Colombia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Nora Cespedes
- Immunology Department, Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Carlos Echeverry
- Immunology Department, Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Eduardo Solano
- Immunology Department, Caucaseco Scientific Research Center, Cali, Colombia
| | - Angélica Castellanos
- Immunology Department, Malaria Vaccine and Drug Development Center, Cali, Colombia
| | | | - Adolfo Miranda
- Parasitology Department, Centro Nacional de Epidemiología (CNE), Guatemala City, Guatemala
| | - Andrey V. Kajava
- Centre de Recherche en Biologie Cellulaire de Montpellier, Université Montpellier, Montpellier, France
| | - Carole Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | | | - Sócrates Herrera
- Immunology Department, Malaria Vaccine and Drug Development Center, Cali, Colombia
- Immunology Department, Caucaseco Scientific Research Center, Cali, Colombia
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107
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Roy K, Roy S, Roy S. A mimotope attached to an ITIM-SHP-1 interaction inhibitory peptide boosts immune response and efficacy. RSC Med Chem 2021; 12:994-999. [PMID: 34223164 PMCID: PMC8221254 DOI: 10.1039/d1md00099c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 04/26/2021] [Indexed: 11/21/2022] Open
Abstract
Antigen binding to the B-cell receptor initiates a downstream signalling pathway that contains both stimulatory and damping components. A malarial parasite-derived conformation-constrained peptide was conjugated to a signal-damping pathway inhibitor. Mice immunized with this antigen produced higher antibody levels which delayed parasitemia. This represents a new approach to antigen design.
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Affiliation(s)
- Koushik Roy
- Division of Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology 4, Raja S.C.Mullick Road Kolkata 700032 India
| | - Syamal Roy
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology 4, Raja S.C. Mullick Road Kolkata 700032 India
| | - Siddhartha Roy
- Department of Biophysics, Bose Institute P1/12, CIT Scheme VII M Kolkata 700054 India
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108
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Tripathi AK, Oakley MS, Verma N, Mlambo G, Zheng H, Meredith SM, Essuman E, Puri A, Skelton RA, Takeda K, Majam V, Quakyi IA, Locke E, Morin M, Miura K, Long CA, Kumar S. Plasmodium falciparum Pf77 and male development gene 1 as vaccine antigens that induce potent transmission-reducing antibodies. Sci Transl Med 2021; 13:eabg2112. [PMID: 34108248 PMCID: PMC11018285 DOI: 10.1126/scitranslmed.abg2112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/22/2021] [Indexed: 12/14/2022]
Abstract
Malaria vaccines that disrupt the Plasmodium life cycle in mosquitoes and reduce parasite transmission in endemic areas are termed transmission-blocking vaccines (TBVs). Despite decades of research, there are only a few Plasmodium falciparum antigens that indisputably and reproducibly demonstrate transmission-blocking immunity. So far, only two TBV candidates have advanced to phase 1/2 clinical testing with limited success. By applying an unbiased transcriptomics-based approach, we have identified Pf77 and male development gene 1 (PfMDV-1) as two P. falciparum TBV antigens that, upon immunization, induced antibodies that caused reductions in oocyst counts in Anopheles mosquito midguts in a standard membrane feeding assay. In-depth studies were performed to characterize the genetic diversity of, stage-specific expression by, and natural immunity to these two molecules to evaluate their suitability as TBV candidates. Pf77 and PfMDV-1 display limited antigenic polymorphism, are pan-developmentally expressed within the parasite, and induce naturally occurring antibodies in Ghanaian adults, which raises the prospect of natural boosting of vaccine-induced immune response in endemic regions. Together, these biological properties suggest that Pf77 and PfMDV-1 may warrant further investigation as TBV candidates.
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Affiliation(s)
- Abhai K Tripathi
- Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Miranda S Oakley
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Nitin Verma
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Godfree Mlambo
- Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Hong Zheng
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Scott M Meredith
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Edward Essuman
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Ankit Puri
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Richard A Skelton
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Kazuyo Takeda
- Division of Bacterial, Parasitic, and Allergenic Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Victoria Majam
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA
| | | | - Emily Locke
- PATH-Malaria Vaccine Initiative, Washington, DC 20001, USA
| | | | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA.
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109
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Okombo J, Kanai M, Deni I, Fidock DA. Genomic and Genetic Approaches to Studying Antimalarial Drug Resistance and Plasmodium Biology. Trends Parasitol 2021; 37:476-492. [PMID: 33715941 PMCID: PMC8162148 DOI: 10.1016/j.pt.2021.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/14/2022]
Abstract
Recent progress in genomics and molecular genetics has empowered novel approaches to study gene functions in disease-causing pathogens. In the human malaria parasite Plasmodium falciparum, the application of genome-based analyses, site-directed genome editing, and genetic systems that allow for temporal and quantitative regulation of gene and protein expression have been invaluable in defining the genetic basis of antimalarial resistance and elucidating candidate targets to accelerate drug discovery efforts. Using examples from recent studies, we review applications of some of these approaches in advancing our understanding of Plasmodium biology and illustrate their contributions and limitations in characterizing parasite genomic loci associated with antimalarial drug responses.
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Affiliation(s)
- John Okombo
- Department of Microbiology & Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Mariko Kanai
- Department of Microbiology & Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Ioanna Deni
- Department of Microbiology & Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - David A Fidock
- Department of Microbiology & Immunology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.
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110
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A single-cell atlas of Plasmodium falciparum transmission through the mosquito. Nat Commun 2021; 12:3196. [PMID: 34045457 PMCID: PMC8159942 DOI: 10.1038/s41467-021-23434-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/28/2021] [Indexed: 01/29/2023] Open
Abstract
Malaria parasites have a complex life cycle featuring diverse developmental strategies, each uniquely adapted to navigate specific host environments. Here we use single-cell transcriptomics to illuminate gene usage across the transmission cycle of the most virulent agent of human malaria - Plasmodium falciparum. We reveal developmental trajectories associated with the colonization of the mosquito midgut and salivary glands and elucidate the transcriptional signatures of each transmissible stage. Additionally, we identify both conserved and non-conserved gene usage between human and rodent parasites, which point to both essential mechanisms in malaria transmission and species-specific adaptations potentially linked to host tropism. Together, the data presented here, which are made freely available via an interactive website, provide a fine-grained atlas that enables intensive investigation of the P. falciparum transcriptional journey. As well as providing insights into gene function across the transmission cycle, the atlas opens the door for identification of drug and vaccine targets to stop malaria transmission and thereby prevent disease. Here the authors use single-cell RNA-seq to profile the transmission stages of the human malaria parasite Plasmodium falciparum as it progresses through the Anopheles mosquito. They highlight unique patterns of gene usage throughout this development and identify potential pleiotropic genes that function at multiple life cycle stages.
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111
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Moita D, Nunes-Cabaço H, Mendes AM, Prudêncio M. A guide to investigating immune responses elicited by whole-sporozoite pre-erythrocytic vaccines against malaria. FEBS J 2021; 289:3335-3359. [PMID: 33993649 DOI: 10.1111/febs.16016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/19/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022]
Abstract
In the last few decades, considerable efforts have been made toward the development of efficient vaccines against malaria. Whole-sporozoite (Wsp) vaccines, which induce efficient immune responses against the pre-erythrocytic (PE) stages (sporozoites and liver forms) of Plasmodium parasites, the causative agents of malaria, are among the most promising immunization strategies tested until present. Several Wsp PE vaccination approaches are currently under evaluation in the clinic, including radiation- or genetically-attenuated Plasmodium sporozoites, live parasites combined with chemoprophylaxis, or genetically modified rodent Plasmodium parasites. In addition to the assessment of their protective efficacy, clinical trials of Wsp PE vaccine candidates inevitably involve the thorough investigation of the immune responses elicited by vaccination, as well as the identification of correlates of protection. Here, we review the main methodologies employed to dissect the humoral and cellular immune responses observed in the context of Wsp PE vaccine clinical trials and discuss future strategies to further deepen the knowledge generated by these studies, providing a toolbox for the in-depth analysis of vaccine-induced immunogenicity.
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Affiliation(s)
- Diana Moita
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Helena Nunes-Cabaço
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - António M Mendes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
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112
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Viswanath VK, Gore ST, Valiyaparambil A, Mukherjee S, Lakshminarasimhan A. Plasmodium chitinases: revisiting a target of transmission-blockade against malaria. Protein Sci 2021; 30:1493-1501. [PMID: 33934433 DOI: 10.1002/pro.4095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 01/21/2023]
Abstract
Malaria is a life-threatening disease caused by one of the five species of Plasmodium, among which Plasmodium falciparum cause the deadliest form of the disease. Plasmodium species are dependent on a vertebrate host and a blood-sucking insect vector to complete their life cycle. Plasmodium chitinases belonging to the GH18 family are secreted inside the mosquito midgut, during the ookinete stage of the parasite. Chitinases mediate the penetration of parasite through the peritrophic membrane, facilitating access to the gut epithelial layer. In this review, we describe Plasmodium chitinases with special emphasis on chitinases from P. falciparum and P. vivax, the representative examples of the short and long forms of this protein. In addition to the chitinase domain, chitinases belonging to the long form contain a pro-domain and chitin-binding domain. Amino acid sequence alignment of long and short form chitinase domains reveals multiple positions containing variant residues. A subset of these positions was found to be conserved or invariant within long or short forms, indicating the role of these positions in attributing form-specific activity. The reported differences in affinities to allosamidin for P. vivax and P. falciparum were predicted to be due to different residues at two amino acid positions, resulting in altered interactions with the inhibitor. Understanding the role of these amino acids in Plasmodium chitinases will help us elucidate the mechanism of catalysis and the mode of inhibition, which will be the key for identification of potent inhibitors or antibodies demonstrating transmission-blocking activity.
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Affiliation(s)
- Vysakh K Viswanath
- Tata Institute for Genetics and Society, Center at inStem, Bengaluru, India
| | - Suraj T Gore
- Aurigene Discovery Technologies Ltd, Bengaluru, India
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113
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Tucker KD, Schanen BC, Phares TW, Sassano E, Terry FE, Hindocha P, Moise L, Kotraiah V, Martin WD, De Groot AS, Drake DR, Gutierrez GM, Noe AR. Identification, Selection and Immune Assessment of Liver Stage CD8 T Cell Epitopes From Plasmodium falciparum. Front Immunol 2021; 12:684116. [PMID: 34025684 PMCID: PMC8138313 DOI: 10.3389/fimmu.2021.684116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/13/2021] [Indexed: 11/13/2022] Open
Abstract
Immunization with radiation-attenuated sporozoites (RAS) has been shown to protect against malaria infection, primarily through CD8 T cell responses, but protection is limited based on parasite strain. Therefore, while CD8 T cells are an ideal effector population target for liver stage malaria vaccine development strategies, such strategies must incorporate conserved epitopes that cover a large range of class I human leukocyte antigen (HLA) supertypes to elicit cross-strain immunity across the target population. This approach requires identifying and characterizing a wide range of CD8 T cell epitopes for incorporation into a vaccine such that coverage across a large range of class I HLA alleles is attained. Accordingly, we devised an experimental framework to identify CD8 T cell epitopes from novel and minimally characterized antigens found at the pre-erythrocytic stage of parasite development. Through in silico analysis we selected conserved P. falciparum proteins, using P. vivax orthologues to establish stringent conservation parameters, predicted to have a high number of T cell epitopes across a set of six class I HLA alleles representative of major supertypes. Using the decision framework, five proteins were selected based on the density and number of predicted epitopes. Selected epitopes were synthesized as peptides and evaluated for binding to the class I HLA alleles in vitro to verify in silico binding predictions, and subsequently for stimulation of human T cells using the Modular IMmune In-vitro Construct (MIMIC®) technology to verify immunogenicity. By combining the in silico tools with the ex vivo high throughput MIMIC platform, we identified 15 novel CD8 T cell epitopes capable of stimulating an immune response in alleles across the class I HLA panel. We recommend these epitopes should be evaluated in appropriate in vivo humanized immune system models to determine their protective efficacy for potential inclusion in future vaccines.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Anne S. De Groot
- EpiVax Inc., Providence, RI, United States
- University of Georgia Center for Vaccines and Immunology, Athens, GA, United States
| | | | | | - Amy R. Noe
- Leidos Life Sciences, Leidos Inc., Frederick, MD, United States
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114
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Systems analysis and controlled malaria infection in Europeans and Africans elucidate naturally acquired immunity. Nat Immunol 2021; 22:654-665. [PMID: 33888898 DOI: 10.1038/s41590-021-00911-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/02/2021] [Indexed: 01/31/2023]
Abstract
Controlled human infections provide opportunities to study the interaction between the immune system and malaria parasites, which is essential for vaccine development. Here, we compared immune signatures of malaria-naive Europeans and of Africans with lifelong malaria exposure using mass cytometry, RNA sequencing and data integration, before and 5 and 11 days after venous inoculation with Plasmodium falciparum sporozoites. We observed differences in immune cell populations, antigen-specific responses and gene expression profiles between Europeans and Africans and among Africans with differing degrees of immunity. Before inoculation, an activated/differentiated state of both innate and adaptive cells, including elevated CD161+CD4+ T cells and interferon-γ production, predicted Africans capable of controlling parasitemia. After inoculation, the rapidity of the transcriptional response and clusters of CD4+ T cells, plasmacytoid dendritic cells and innate T cells were among the features distinguishing Africans capable of controlling parasitemia from susceptible individuals. These findings can guide the development of a vaccine effective in malaria-endemic regions.
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115
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Loubens M, Vincensini L, Fernandes P, Briquet S, Marinach C, Silvie O. Plasmodium sporozoites on the move: Switching from cell traversal to productive invasion of hepatocytes. Mol Microbiol 2021; 115:870-881. [PMID: 33191548 PMCID: PMC8247013 DOI: 10.1111/mmi.14645] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/18/2022]
Abstract
Parasites of the genus Plasmodium, the etiological agent of malaria, are transmitted through the bite of anopheline mosquitoes, which deposit sporozoites into the host skin. Sporozoites migrate through the dermis, enter the bloodstream, and rapidly traffic to the liver. They cross the liver sinusoidal barrier and traverse several hepatocytes before switching to productive invasion of a final one for replication inside a parasitophorous vacuole. Cell traversal and productive invasion are functionally independent processes that require proteins secreted from specialized secretory organelles known as micronemes. In this review, we summarize the current understanding of how sporozoites traverse through cells and productively invade hepatocytes, and discuss the role of environmental sensing in switching from a migratory to an invasive state. We propose that timely controlled secretion of distinct microneme subsets could play a key role in successful migration and infection of hepatocytes. A better understanding of these essential biological features of the Plasmodium sporozoite may contribute to the development of new strategies to fight against the very first and asymptomatic stage of malaria.
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Affiliation(s)
- Manon Loubens
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Laetitia Vincensini
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Priyanka Fernandes
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Sylvie Briquet
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Carine Marinach
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Olivier Silvie
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
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116
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Arez F, Rodrigues AF, Brito C, Alves PM. Bioengineered Liver Cell Models of Hepatotropic Infections. Viruses 2021; 13:773. [PMID: 33925701 PMCID: PMC8146083 DOI: 10.3390/v13050773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 02/07/2023] Open
Abstract
Hepatitis viruses and liver-stage malaria are within the liver infections causing higher morbidity and mortality rates worldwide. The highly restricted tropism of the major human hepatotropic pathogens-namely, the human hepatitis B and C viruses and the Plasmodium falciparum and Plasmodium vivax parasites-has hampered the development of disease models. These models are crucial for uncovering the molecular mechanisms underlying the biology of infection and governing host-pathogen interaction, as well as for fostering drug development. Bioengineered cell models better recapitulate the human liver microenvironment and extend hepatocyte viability and phenotype in vitro, when compared with conventional two-dimensional cell models. In this article, we review the bioengineering tools employed in the development of hepatic cell models for studying infection, with an emphasis on 3D cell culture strategies, and discuss how those tools contributed to the level of recapitulation attained in the different model layouts. Examples of host-pathogen interactions uncovered by engineered liver models and their usefulness in drug development are also presented. Finally, we address the current bottlenecks, trends, and prospect toward cell models' reliability, robustness, and reproducibility.
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MESH Headings
- Animals
- Bioengineering/methods
- Cell Culture Techniques
- Disease Models, Animal
- Disease Susceptibility
- Drug Discovery
- Hepatitis/drug therapy
- Hepatitis/etiology
- Hepatitis/metabolism
- Hepatitis/pathology
- Hepatitis, Viral, Human/etiology
- Hepatitis, Viral, Human/metabolism
- Hepatitis, Viral, Human/pathology
- Hepatocytes/metabolism
- Hepatocytes/parasitology
- Hepatocytes/virology
- Host-Pathogen Interactions
- Humans
- Liver/metabolism
- Liver/parasitology
- Liver/virology
- Liver Diseases, Parasitic/etiology
- Liver Diseases, Parasitic/metabolism
- Liver Diseases, Parasitic/pathology
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Affiliation(s)
- Francisca Arez
- iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; (F.A.); (A.F.R.); (C.B.)
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ana F. Rodrigues
- iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; (F.A.); (A.F.R.); (C.B.)
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Catarina Brito
- iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; (F.A.); (A.F.R.); (C.B.)
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- The Discoveries Centre for Regenerative and Precision Medicine, Lisbon Campus, Av. da República, 2780-157 Oeiras, Portugal
| | - Paula M. Alves
- iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; (F.A.); (A.F.R.); (C.B.)
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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117
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McCoy KD, Weldon CT, Ansumana R, Lamin JM, Stenger DA, Ryan SJ, Bardosh K, Jacobsen KH, Dinglasan RR. Are malaria transmission-blocking vaccines acceptable to high burden communities? Results from a mixed methods study in Bo, Sierra Leone. Malar J 2021; 20:183. [PMID: 33849572 PMCID: PMC8045381 DOI: 10.1186/s12936-021-03723-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 04/04/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Malaria transmission-blocking vaccines (TBVs) could help break the cycle of malaria transmission by conferring community rather than individual protection. When introducing new intervention strategies, uptake is dependent on acceptability, not just efficacy. In this exploratory study on acceptability of TBVs in Sierra Leone, it was hypothesized that TBVs would be largely acceptable to adults and health workers in areas with relatively few ongoing malaria interventions, and that (i) knowledge of malaria and vaccines, (ii) health behaviours associated with malaria and vaccines, and (iii) attitudes towards different vaccines types could lead to greater TBV acceptability. METHODS This study used a mixed methods approach in Bo, Sierra Leone, to understand community knowledge, attitudes, and practices related to malaria and vaccination in general. This included: (i) a population-based cross-sectional survey (n=615 adults), (ii) 6 focus group discussions with parents, and (iii) 20 key informant interviews. The concept of a TBV was explained to participants before they were asked about their willingness to accept this vaccine modality as part of an integrated malaria elimination programme. RESULTS This study found that most adults would be willing to receive a TBV vaccine. Respondents noted mostly positive past experiences with adult and childhood vaccinations for other infectious diseases and high levels of engagement in other malaria prevention behaviors such as bed nets. Perceived barriers to TBV acceptance were largely focused on general community-level distribution of a vaccine, including personal fears of vaccination and possible costs. After an explanation of the TBV mechanism, nearly all focus group and interview participants believed that community members would accept the vaccine as part of an integrated malaria control approach. Both parents and health workers offered insight on how to successfully roll-out a future TBV vaccination programme. CONCLUSIONS The willingness of community members in Bo, Sierra Leone to accept a TBV as part of an integrated anti-malarial strategy suggests that the atypical mechanism of TBV action might not be an obstacle to future clinical trials. This study's findings suggests that perceived general barriers to vaccination implementation, such as perceived personal fears and vaccine cost, must be addressed in future clinical and implementation research studies.
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Affiliation(s)
- Kaci D McCoy
- CDC Southeastern Center of Excellence in Vector Borne Diseases, Gainesville, FL, USA
- Emerging Pathogens Institute, Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Caroline T Weldon
- CDC Southeastern Center of Excellence in Vector Borne Diseases, Gainesville, FL, USA
| | - Rashid Ansumana
- Mercy Hospital Research Laboratory, Bo, Sierra Leone
- School of Community Health Sciences, Njala University, Bo, Sierra Leone
| | | | - David A Stenger
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC, USA
| | - Sadie J Ryan
- CDC Southeastern Center of Excellence in Vector Borne Diseases, Gainesville, FL, USA
- Emerging Pathogens Institute, Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
- Department of Geography, College of Liberal Arts & Sciences, University of Florida, Gainesville, FL, USA
| | - Kevin Bardosh
- Center for One Health Research, School of Public Health, University of Washington, Seattle, WA, USA
| | - Kathryn H Jacobsen
- Department of Global and Community Health, College of Health and Human Services, George Mason University, Fairfax, VA, USA
| | - Rhoel R Dinglasan
- CDC Southeastern Center of Excellence in Vector Borne Diseases, Gainesville, FL, USA.
- Emerging Pathogens Institute, Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.
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118
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Vaughan A. Motile mosquito stage malaria parasites: ready for their close-up. EMBO Mol Med 2021; 13:e13975. [PMID: 33787077 PMCID: PMC8033511 DOI: 10.15252/emmm.202113975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 02/01/2023] Open
Abstract
Many stages of the complex Plasmodium parasite life cycle, the eukaryotic pathogen that causes malaria, are extracellular and motile. This motility is essential for life cycle progression, and two studies in this issue of EMBO Molecular Medicine (Hopp et al, 2021; Ripp et al, 2021) examine the motility of two of these life cycle stages. These are the ookinete, which develops in the midgut of an infected mosquito vector, and the sporozoite, which is injected into the skin of an unsuspecting host by an infected mosquito, initiating the parasite life cycle in the human. Therapeutic targeting of the ookinete and sporozoite (Duffy & Patrick Gorres, 2020), which are profound bottlenecks in the life cycle, has recently received a great deal of attention in our battle to prevent the 400,000 deaths from malaria that occur every year (WHO, 2020).
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Affiliation(s)
- Ashley Vaughan
- Center for Global Infectious Disease ResearchSeattle Children's Research InstituteSeattleWAUSA
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119
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França ACB, Françoso KS, Marques RF, Trossini GHG, Gomes RA, Póvoa MM, Cunha MG, Silveira ELV, Soares IS. Antibodies Against the Plasmodium vivax Apical Membrane Antigen 1 From the Belem Strain Share Common Epitopes Among Other Worldwide Variants. Front Cell Infect Microbiol 2021; 11:616230. [PMID: 33796476 PMCID: PMC8009186 DOI: 10.3389/fcimb.2021.616230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 02/23/2021] [Indexed: 12/31/2022] Open
Abstract
Malaria is a human parasitic disease distributed in many tropical countries and caused by various Plasmodium species. Plasmodium vivax has the largest geographical distribution of the Plasmodium species and is predominant in the Americas, including Brazil. Only a small number of P. vivax vaccine formulations have successfully reached clinical trials relative to their P. falciparum counterparts. One of the candidate antigens for a blood-stage P. vivax vaccine is apical membrane antigen 1 (PvAMA-1). Due to the worldwide distribution of Plasmodium parasites, a high degree of variability has been detected in this antigen sequence, representing a considerable challenge to the development of a universal vaccine against malaria. In this study, we evaluated how PvAMA-1 polymorphisms influence vaccine-derived immune responses in P. vivax malaria. To this end, we expressed 9 recombinant protein representatives of different PvAMA-1 allelic variants in the yeast Pichia pastoris: Belem, Chesson I, Sal-1, Indonesia XIX, SK0814, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS. After protein expression and purification, we evaluated the breadth of the immune responses derived from malaria-exposed individuals from the Amazon region. From 611 serum samples of malaria-exposed individuals, 53.68% of them reacted against the PvAMA-1 Belem through ELISA. Positive samples were further tested against recombinant proteins representing the other PvAMA-1 allelic variants. Whereas Sal-1, Chesson I and SK0814 variants were highly recognized by tested serum samples, Indonesia XIX, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS were only slightly recognized. Moreover, polyclonal sera derived from C57BL/6 mice immunized with the PvAMA-1 Belem protein predominantly recognized Belem, Sal-1, Chesson I, SK0814, and Indonesia XIX through ELISA. Last, ELISA-based competition assays demonstrated that a previous interaction between anti-Belem polyclonal serum and Sal-1, Chesson I, SK0814, or Indonesia XIX proteins could further inhibit antibody binding to the Belem variant. Our human and mouse data suggest the presence of common epitopes or cross-reactivity between Belem, Sal-1, Chesson I, and SK0814 variants. Although the PvAMA-1 Belem variant induces strain-transcendent antibodies, PvAMA-1 variants from Thailand and Papua New Guinea may need to be included in a universal vaccine formulation to achieve protection against P. vivax malaria.
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Affiliation(s)
- Ana Caroline Barbosa França
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Kátia Sanches Françoso
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rodolfo Ferreira Marques
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Gustavo H. G. Trossini
- Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Renan A. Gomes
- Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | | | - Maristela G. Cunha
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Eduardo L. V. Silveira
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Irene S. Soares
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
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120
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Arora N, C Anbalagan L, Pannu AK. Towards Eradication of Malaria: Is the WHO's RTS,S/AS01 Vaccination Effective Enough? Risk Manag Healthc Policy 2021; 14:1033-1039. [PMID: 33737844 PMCID: PMC7966294 DOI: 10.2147/rmhp.s219294] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/26/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Recent advances in mosquito eradication and antimalarial treatments have reduced the malaria burden only modestly. An effective malaria vaccine remains a high priority, but its development has several challenges. Among many potential candidates, the RTS,S/AS01 vaccine (MosquirixTM) remains the leading candidate. OBJECTIVE AND METHOD This review aims to understand the advances in the RTS,S/AS01 vaccine, and future comments regarding the vaccine's effectiveness in malaria eradication. Literature review for the past five decades was performed searching PubMed, EMBASE Ovid, and Cochrane Library, with using the following search items: ("malaria" OR "WHO's malaria" OR "Plasmodium falciparum" OR "RTS,S" OR "RTS,S/AS01" OR "RTS,S/AS02" OR "pre-erythrocytic malaria" OR "circumsporozoite" OR "Mosquirix") AND ("vaccine" OR "vaccination"). RESULTS RTS,S/AS01, a recombinant pre-erythrocytic vaccine containing Plasmodium falciparum surface-protein (circumsporozoite) antigen, is safe, well-tolerated, and immunogenic in children. Three doses, along with a booster, have a modest efficacy of about 36% in children (age 5-17 months) and about 26% in infants (age 6-12 weeks) against clinical malaria during a 48-month follow-up. However, the efficacy varies among population subgroups and with the parasite strain, it reduces without a booster and offers protection for a limited duration. Because of its potential cost-effectiveness and positive public health effect, the vaccine is being investigated in a pilot program for mortality benefits and broader deployment. CONCLUSION The RTS,S/AS01 vaccine prevents malaria; however, it should be considered another addition to the malaria-control program and not as an eradication tool because of its relatively low to modest efficacy.
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Affiliation(s)
- Navneet Arora
- Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | | | - Ashok K Pannu
- Postgraduate Institute of Medical Education and Research, Chandigarh, India
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121
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Abstract
Introduction: An effective vaccine against malaria forms a global health priority. Both naturally acquired immunity and sterile protection induced by irradiated sporozoite immunization were described decades ago. Still no vaccine exists that sufficiently protects children in endemic areas. Identifying immunological correlates of vaccine efficacy can inform rational vaccine design and potentially accelerate clinical development.Areas covered: We discuss recent research on immunological correlates of malaria vaccine efficacy, including: insights from state-of-the-art omics platforms and systems vaccinology analyses; functional anti-parasitic assays; pre-immunization predictors of vaccine efficacy; and comparison of correlates of vaccine efficacy against controlled human malaria infections (CHMI) and against naturally acquired infections.Expert Opinion: Effective vaccination may be achievable without necessarily understanding immunological correlates, but the relatively disappointing efficacy of malaria vaccine candidates in target populations is concerning. Hypothesis-generating omics and systems vaccinology analyses, alongside assessment of pre-immunization correlates, have the potential to bring about paradigm-shifts in malaria vaccinology. Functional assays may represent in vivo effector mechanisms, but have scarcely been formally assessed as correlates. Crucially, evidence is still meager that correlates of vaccine efficacy against CHMI correspond with those against naturally acquired infections in target populations. Finally, the diversity of immunological assays and efficacy endpoints across malaria vaccine trials remains a major confounder.
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Affiliation(s)
| | - Matthew B B McCall
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands.,Institut für Tropenmedizin, Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
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122
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Hamada S, Pionneau C, Parizot C, Silvie O, Chardonnet S, Marinach C. In-depth proteomic analysis of Plasmodium berghei sporozoites using trapped ion mobility spectrometry with parallel accumulation-serial fragmentation. Proteomics 2021; 21:e2000305. [PMID: 33452840 DOI: 10.1002/pmic.202000305] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 11/11/2022]
Abstract
Sporozoites of the malaria parasite Plasmodium are transmitted by mosquitoes and infect the liver for an initial and obligatory round of replication, before exponential multiplication in the blood and onset of the disease. Sporozoites and liver stages provide attractive targets for malaria vaccines and prophylactic drugs. In this context, defining the parasite proteome is important to explore the parasite biology and to identify potential targets for antimalarial strategies. Previous studies have determined the total proteome of sporozoites from the two main human malaria parasites, P. falciparum and P. vivax, as well as P. yoelii, which infects rodents. Another murine malaria parasite, P. berghei, is widely used to investigate the parasite biology. However, a deep view of the proteome of P. berghei sporozoites is still missing. To fill this gap, we took advantage of the highly sensitive timsTOF PRO mass spectrometer, combined with three alternative methods for sporozoite purification, to identify the proteome of P. berghei sporozoites using low numbers of parasites. This study provides a reference proteome for P. berghei sporozoites, identifying a core set of proteins expressed across species, and illustrates how the unprecedented sensitivity of the timsTOF PRO system enables deep proteomic analysis from limited sample amounts.
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Affiliation(s)
- Soumia Hamada
- Sorbonne Université, INSERM, UMS PASS, Plateforme Post-génomique de la Pitié Salpêtrière (P3S), Paris, France.,Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Cédric Pionneau
- Sorbonne Université, INSERM, UMS PASS, Plateforme Post-génomique de la Pitié Salpêtrière (P3S), Paris, France
| | - Christophe Parizot
- Sorbonne Université, INSERM, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Assistance Publique Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Paris, France
| | - Olivier Silvie
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Solenne Chardonnet
- Sorbonne Université, INSERM, UMS PASS, Plateforme Post-génomique de la Pitié Salpêtrière (P3S), Paris, France
| | - Carine Marinach
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
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123
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Sena-dos-Santos C, Braga-da-Silva C, Marques D, Azevedo dos Santos Pinheiro J, Ribeiro-dos-Santos Â, Cavalcante GC. Unraveling Cell Death Pathways during Malaria Infection: What Do We Know So Far? Cells 2021; 10:479. [PMID: 33672278 PMCID: PMC7926694 DOI: 10.3390/cells10020479] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/07/2020] [Accepted: 12/11/2020] [Indexed: 12/15/2022] Open
Abstract
Malaria is a parasitic disease (caused by different Plasmodium species) that affects millions of people worldwide. The lack of effective malaria drugs and a vaccine contributes to this disease, continuing to cause major public health and socioeconomic problems, especially in low-income countries. Cell death is implicated in malaria immune responses by eliminating infected cells, but it can also provoke an intense inflammatory response and lead to severe malaria outcomes. The study of the pathophysiological role of cell death in malaria in mammalians is key to understanding the parasite-host interactions and design prophylactic and therapeutic strategies for malaria. In this work, we review malaria-triggered cell death pathways (apoptosis, autophagy, necrosis, pyroptosis, NETosis, and ferroptosis) and we discuss their potential role in the development of new approaches for human malaria therapies.
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Affiliation(s)
- Camille Sena-dos-Santos
- Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém 66.075-110, Brazil; (C.S.-d.-S.); (C.B.-d.-S.); (D.M.); (J.A.d.S.P.); (Â.R.-d.-S.)
| | - Cíntia Braga-da-Silva
- Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém 66.075-110, Brazil; (C.S.-d.-S.); (C.B.-d.-S.); (D.M.); (J.A.d.S.P.); (Â.R.-d.-S.)
| | - Diego Marques
- Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém 66.075-110, Brazil; (C.S.-d.-S.); (C.B.-d.-S.); (D.M.); (J.A.d.S.P.); (Â.R.-d.-S.)
| | - Jhully Azevedo dos Santos Pinheiro
- Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém 66.075-110, Brazil; (C.S.-d.-S.); (C.B.-d.-S.); (D.M.); (J.A.d.S.P.); (Â.R.-d.-S.)
| | - Ândrea Ribeiro-dos-Santos
- Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém 66.075-110, Brazil; (C.S.-d.-S.); (C.B.-d.-S.); (D.M.); (J.A.d.S.P.); (Â.R.-d.-S.)
- Programa de Pós-Graduação em Oncologia e Ciências Médicas, Núcleo de Pesquisas em Oncologia, Universidade Federal do Pará, Belém 66.075-110, Brazil
| | - Giovanna C. Cavalcante
- Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém 66.075-110, Brazil; (C.S.-d.-S.); (C.B.-d.-S.); (D.M.); (J.A.d.S.P.); (Â.R.-d.-S.)
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De SL, Ntumngia FB, Nicholas J, Adams JH. Progress towards the development of a P. vivax vaccine. Expert Rev Vaccines 2021; 20:97-112. [PMID: 33481638 PMCID: PMC7994195 DOI: 10.1080/14760584.2021.1880898] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Plasmodium vivax causes significant public health problems in endemic regions. A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the development of hypnozoites in the liver with potential for relapse. A minimally effective vaccine should prevent disease and transmission while an ideal vaccine provides sterile immunity. AREAS COVERED Despite decades of research, the complex life cycle, technical challenges and a lack of funding have hampered progress of P. vivax vaccine development. Here, we review the progress of potential P. vivax vaccine candidates from different stages of the parasite life cycle. We also highlight the challenges and important strategies for rational vaccine design. These factors can significantly increase immune effector mechanisms and improve the protective efficacy of these candidates in clinical trials to generate sustained protection over longer periods of time. EXPERT OPINION A vaccine that presents functionally-conserved epitopes from multiple antigens from various stages of the parasite life cycle is key to induce broadly neutralizing strain-transcending protective immunity to effectively disrupt parasite development and transmission.
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Affiliation(s)
- Sai Lata De
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Justin Nicholas
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
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125
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Duffy PE. Transmission-Blocking Vaccines: Harnessing Herd Immunity for Malaria Elimination. Expert Rev Vaccines 2021; 20:185-198. [PMID: 33478283 PMCID: PMC11127254 DOI: 10.1080/14760584.2021.1878028] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/14/2021] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Transmission-blocking vaccines (TBV) prevent community spread of malaria by targeting mosquito sexual stage parasites, a life-cycle bottleneck, and will be used in elimination programs. TBV rely on herd immunity to reduce mosquito infections and thereby new infections in both vaccine recipients and non-recipients, but do not provide protection once an individual receives an infectious mosquito bite which complicates clinical development. AREAS COVERED Here, we describe the concept and biology behind TBV, and we provide an update on clinical development of the leading vaccine candidate antigens. Search terms 'malaria vaccine,' 'sexual stages,' 'transmission blocking vaccine,' 'VIMT' and 'SSM-VIMT' were used for PubMed queries to identify relevant literature. EXPERT OPINION Candidates targeting P. falciparum zygote surface antigen Pfs25, and its P. vivax orthologue Pvs25, induced functional activity in humans that reduced mosquito infection in surrogate assays, but require increased durability to be useful in the field. Candidates targeting gamete surface antigens Pfs230 and Pfs48/45, respectively, are in or nearing clinical trials. Nanoparticle platforms and adjuvants are being explored to enhance immunogenicity. Efficacy trials require special considerations, such as cluster-randomized designs to measure herd immunity that reduces human and mosquito infection rates, while addressing human and mosquito movements as confounding factors.
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Affiliation(s)
- Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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126
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Patel PN, Tolia N. Structural vaccinology of malaria transmission-blocking vaccines. Expert Rev Vaccines 2021; 20:199-214. [PMID: 33430656 PMCID: PMC11077433 DOI: 10.1080/14760584.2021.1873135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/16/2020] [Indexed: 02/06/2023]
Abstract
Introduction: The development of effective vaccines remains a major health priority to combat the global burden of malaria, a life-threatening disease caused by Plasmodium parasites. Transmission-blocking vaccines (TBVs) elicit antibodies that neutralize the sexual stages of the parasite in blood meals ingested by the Anopheles mosquito, interrupting parasite development in the vector host and preventing disease spread to other individuals.Areas covered: The P. falciparum gametocyte surface antigens Pfs230, Pfs48/45, and Pfs47, the parasite ookinete surface protein Pfs25, and the male gametocyte specific protein PfHAP2 are leading TBV candidates, some of which are in clinical development. The recent expansion of methodology to study monoclonal antibodies isolated directly from humans and animal models, coupled with effective measures for parasite neutralization, has provided unprecedented insight into TBV efficacy and development.Expert opinion: Available structural and functional data on antigen-monoclonal antibody (Ag-mAb) complexes, as well as epitope classification studies, have identified neutralizing epitopes that may aid vaccine development and improve protection. Here, we review the clinical prospects of TBV candidates, progress in the development of novel vaccine strategies for TBVs, and the impact of structural vaccinology in TBV design.
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Affiliation(s)
- Palak N Patel
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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127
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Patra KP, Kaur H, Kolli SK, Wozniak JM, Prieto JH, Yates JR, Gonzalez DJ, Janse CJ, Vinetz JM. A Hetero-Multimeric Chitinase-Containing Plasmodium falciparum and Plasmodium gallinaceum Ookinete-Secreted Protein Complex Involved in Mosquito Midgut Invasion. Front Cell Infect Microbiol 2021; 10:615343. [PMID: 33489941 PMCID: PMC7821095 DOI: 10.3389/fcimb.2020.615343] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022] Open
Abstract
Malaria parasites are transmitted by Anopheles mosquitoes. During its life cycle in the mosquito vector the Plasmodium ookinete escapes the proteolytic milieu of the post-blood meal midgut by traversing the midgut wall. This process requires penetration of the chitin-containing peritrophic matrix lining the midgut epithelium, which depends in part on ookinete-secreted chitinases. Plasmodium falciparum ookinetes have one chitinase (PfCHT1), whereas ookinetes of the avian-infecting parasite, P. gallinaceum, have two, a long and a short form, PgCHT1 and PgCHT2, respectively. Published data indicates that PgCHT2 forms a high molecular weight (HMW) reduction-sensitive complex; and one binding partner is the ookinete-produced von Willebrand A-domain-containing protein, WARP. Size exclusion chromatography data reported here show that P. gallinaceum PgCHT2 and its ortholog, P. falciparum PfCHT1 are covalently-linked components of a HMW chitinase-containing complex (> 1,300 kDa). Mass spectrometry of ookinete-secreted proteins isolated using a new chitin bead pull-down method identified chitinase-associated proteins in P. falciparum and P. gallinaceum ookinete-conditioned culture media. Mass spectrometry of this complex showed the presence of several micronemal proteins including von Willebrand factor A domain-related protein (WARP), ookinete surface enolase, and secreted ookinete adhesive protein (SOAP). To test the hypothesis that ookinete-produced PfCHT1 can form a high molecular homo-multimer or, alternatively, interacts with P. berghei ookinete-produced proteins to produce an HMW hetero-multimer, we created chimeric P. berghei parasites expressing PfCHT1 to replace PbCHT1, enabling the production of large numbers of PfCHT1-expressing ookinetes. We show that chimeric P. berghei ookinetes express monomeric PfCHT1, but a HMW complex containing PfCHT1 is not present. A better understanding of the chitinase-containing HMW complex may enhance development of next-generation vaccines or drugs that target malaria transmission stages.
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Affiliation(s)
- Kailash P Patra
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Hargobinder Kaur
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
| | - Surendra Kumar Kolli
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Jacob M Wozniak
- Department of Pharmacology and the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States
| | - Judith Helena Prieto
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States.,Department of Chemistry, Western Connecticut State University, Danbury, CT, United States
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - David J Gonzalez
- Department of Pharmacology and the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States
| | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Joseph M Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States
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Bell GJ, Agnandji ST, Asante KP, Ghansah A, Kamthunzi P, Emch M, Bailey JA. Impacts of Ecology, Parasite Antigenic Variation, and Human Genetics on RTS,S/AS01e Malaria Vaccine Efficacy. CURR EPIDEMIOL REP 2021; 8:79-88. [PMID: 34367877 PMCID: PMC8324449 DOI: 10.1007/s40471-021-00271-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Global malaria elimination has little chance of success without an effective vaccine. The first malaria vaccine, RTS,S/AS01e, demonstrated moderate efficacy against clinical malaria in phase III trials and is undergoing large-scale effectiveness trials in Africa. Importantly, the vaccine did not perform equally well between phase III study sites. Though reasons for the moderate efficacy and this variation are unclear, various mechanisms have been suggested. This review summarizes the recent literature on such mechanisms, with a focus on those involving landscape ecology, parasite antigenic variation, and human host genetic differences. RECENT FINDINGS Transmission intensity may have a role pre- and post-vaccination in modulating immune responses to the vaccine. Furthermore, malaria incidence may "rebound" in vaccinated populations living in high transmission intensity settings. There is growing evidence that both genetic variation in the parasite circumsporozoite protein and variation of human host genetic factors affect RTS,S vaccine efficacy. These genetic factors may be interacting in complex ways to produce variation in the natural and vaccine-induced immune responses that protect against malaria. SUMMARY Due to the modest efficacy of RTS,S/AS01e, the combinations of factors (ecological, parasite, human host) impacting its effectiveness must be clearly understood, as this information will be critical for implementation policy and future vaccine designs.
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Affiliation(s)
- Griffin J. Bell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599 USA
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon ,Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | | | - Anita Ghansah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599 USA ,Department of Geography, University of North Carolina, Chapel Hill 220 E Cameron Ave, Chapel Hill, NC 27599 USA
| | - Jeffrey A. Bailey
- Department of Pathology and Laboratory Medicine, Brown University, 55 Claverick St, Rm 314B, Providence, RI 02912 USA
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129
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Kaslow DC. Malaria vaccine research & innovation: the intersection of IA2030 and zero malaria. NPJ Vaccines 2020; 5:109. [PMID: 33298967 PMCID: PMC7677906 DOI: 10.1038/s41541-020-00259-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 10/30/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- David C Kaslow
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA.
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130
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Kanoi BN, Nagaoka H, Morita M, Tsuboi T, Takashima E. Leveraging the wheat germ cell-free protein synthesis system to accelerate malaria vaccine development. Parasitol Int 2020; 80:102224. [PMID: 33137499 DOI: 10.1016/j.parint.2020.102224] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/04/2020] [Accepted: 09/16/2020] [Indexed: 01/29/2023]
Abstract
Vaccines against infectious diseases have had great successes in the history of public health. Major breakthroughs have occurred in the development of vaccine-based interventions against viral and bacterial pathogens through the application of classical vaccine design strategies. In contrast the development of a malaria vaccine has been slow. Plasmodium falciparum malaria affects millions of people with nearly half of the world population at risk of infection. Decades of dedicated research has taught us that developing an effective vaccine will be time consuming, challenging, and expensive. Nevertheless, recent advancements such as the optimization of robust protein synthesis platforms, high-throughput immunoscreening approaches, reverse vaccinology, structural design of immunogens, lymphocyte repertoire sequencing, and the utilization of artificial intelligence, have renewed the prospects of an accelerated discovery of the key antigens in malaria. A deeper understanding of the major factors underlying the immunological and molecular mechanisms of malaria might provide a comprehensive approach to identifying novel and highly efficacious vaccines. In this review we discuss progress in novel antigen discoveries that leverage on the wheat germ cell-free protein synthesis system (WGCFS) to accelerate malaria vaccine development.
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Affiliation(s)
- Bernard N Kanoi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan.
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131
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Repurposing Drugs to Fight Hepatic Malaria Parasites. Molecules 2020; 25:molecules25153409. [PMID: 32731386 PMCID: PMC7435416 DOI: 10.3390/molecules25153409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/16/2022] Open
Abstract
Malaria remains one of the most prevalent infectious diseases worldwide, primarily affecting some of the most vulnerable populations around the globe. Despite achievements in the treatment of this devastating disease, there is still an urgent need for the discovery of new drugs that tackle infection by Plasmodium parasites. However, de novo drug development is a costly and time-consuming process. An alternative strategy is to evaluate the anti-plasmodial activity of compounds that are already approved for other purposes, an approach known as drug repurposing. Here, we will review efforts to assess the anti-plasmodial activity of existing drugs, with an emphasis on the obligatory and clinically silent liver stage of infection. We will also review the current knowledge on the classes of compounds that might be therapeutically relevant against Plasmodium in the context of other communicable diseases that are prevalent in regions where malaria is endemic. Repositioning existing compounds may constitute a faster solution to the current gap of prophylactic and therapeutic drugs that act on Plasmodium parasites, overall contributing to the global effort of malaria eradication.
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