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Lyimo BM, Bakari C, Popkin-Hall ZR, Giesbrecht DJ, Seth MD, Pereus D, Shabani ZI, Moshi R, Boniface R, Mandara CI, Madebe R, Juliano JJ, Bailey JA, Ishengoma DS. Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity. Malar J 2024; 23:139. [PMID: 38720288 PMCID: PMC11080125 DOI: 10.1186/s12936-024-04974-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (PfCSP), but polymorphisms in the gene raise concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission intensities in Mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country. METHODS The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of Mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (Fws), Wright's fixation index (FST), principal component analysis, nucleotide diversity, and Tajima's D were used to assess within-host parasite diversity, population structure and natural selection. RESULTS Based on Fws (< 0.95), there was high polyclonality (ranging from 69.23% in Nachingwea to 56.9% in Muheza). No population structure was detected in the Pfcsp gene in the five regions (mean FST = 0.0068). The average nucleotide diversity (π), nucleotide differentiation (K) and haplotype diversity (Hd) in the five regions were 4.19, 0.973 and 0.0035, respectively. The C-terminal region of Pfcsp showed high nucleotide diversity at Th2R and Th3R regions. Positive values for the Tajima's D were observed in the Th2R and Th3R regions consistent with balancing selection. The Pfcsp C-terminal sequences revealed 50 different haplotypes (H_1 to H_50), with only 2% of sequences matching the 3D7 strain haplotype (H_50). Conversely, with the NF54 strain, the Pfcsp C-terminal sequences revealed 49 different haplotypes (H_1 to H_49), with only 0.4% of the sequences matching the NF54 strain (Hap_49). CONCLUSIONS The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values, consistent with balancing selection for variants within Th2R and Th3R regions. The study observed differences between the intended haplotypes incorporated into the design of RTS,S and R21 vaccines and those present in natural parasite populations. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
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Affiliation(s)
- Beatus M Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania.
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Misago D Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Zulfa I Shabani
- Dar Es Salaam University College of Education, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Ramadhan Moshi
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Ruth Boniface
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Celine I Mandara
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Rashid Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Harvard T.H Chan School of Public Health, Boston, MA, USA
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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Hawadak J, Kojom Foko LP, Dongang Nana RR, Yadav K, Pande V, Das A, Singh V. Genetic diversity and natural selection of apical membrane antigen-1 (ama-1) in Cameroonian Plasmodium falciparum isolates. Gene 2024; 894:147956. [PMID: 37925116 DOI: 10.1016/j.gene.2023.147956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/16/2023] [Accepted: 10/31/2023] [Indexed: 11/06/2023]
Abstract
Antigenic variation associated with genetic diversity in global Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a major impediment to designing an effective malaria vaccine. Here, we report the first study on genetic diversity and natural selection of the Pfama-1 gene in P. falciparum isolates from Cameroon. A total of 328 P. falciparum positive samples collected during 2016 and 2019 from five localities of Cameroon were analysed. The ectodomain coding fragment of Pfama-1 gene was amplified for polymorphism profiling and natural selection analysis. A total of 108 distinct haplotypes were found in 203 P. falciparum isolates with considerable nucleotide diversity (π = 0.016) and haplotype diversity (Hd = 0.976). Most amino acid substitutions detected were scattered in ectodomain-I and few specific mutations viz P145L, K148Q, K462I, L463F, N471K, S482L, E537G, K546R and I547F were seen only in Cameroonian isolates. A tendency of natural selection towards positive diversifying selection was observed (Taj-D = 2.058). Five positively selected codon sites (P145L, S283L, Q308E/K, P330S and I547F) were identified, which overlapped with predicted B-cell epitopes and red blood cell (RBC) binding sites, suggesting their potential implication in host immune pressure and parasite-RBC binding complex modulation. The Cameroonian P. falciparum populations indicated a moderate level of genetic differentiation when compared with global sequences, with few exceptions from Vietnam and Venezuela. Our findings provide baseline data on existing Pfama-1 gene polymorphisms in Cameroonian field isolates, which will be useful information for malaria vaccine design.
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Affiliation(s)
- Joseph Hawadak
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Loick Pradel Kojom Foko
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Rodrigue Roman Dongang Nana
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Institut de Recherches Médicales et D'Etudes des Plantes Médicinales (IMPM), Yaoundé, Cameroon
| | - Karmveer Yadav
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Aparup Das
- ICMR-National Institute for Research in Tribal Health (NIRTH), Jabalpur, India.
| | - Vineeta Singh
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India.
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Lyimo BM, Bakari C, Popkin-Hall ZR, Giesbrecht DJ, Seth MD, Pereus D, Moshi R, Boniface R, Mandara CI, Madebe R, Juliano JJ, Bailey JA, Ishengoma DS. Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.23.24301587. [PMID: 38343796 PMCID: PMC10854334 DOI: 10.1101/2024.01.23.24301587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Background In 2021 and 2023, the World Health Organization approved RTS, S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (Pfcsp) but polymorphisms in this gene raises concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission in mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country. Methods The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (Fws), Wright's fixation index (FST), principal component analysis, nucleotide diversity, and Tajima's D were used to assess within-host parasite diversity, population structure and natural selection. Results Based on Fws (< 0.95), there was high polyclonality (ranged from 69.23% in Nachingwea to 56.9% in Muheza). No population structure was detected in the Pfcsp gene in the five regions (mean FST= 0.0068). The average nucleotide diversity (π), nucleotide differentiation (K) and haplotype diversity (Hd) in the five regions were 4.19, 0.973 and 0.0035, respectively. The C-terminal region of Pfcsp showed high nucleotide diversity at Th2R and Th3R regions. Positive values for the Tajima's D were observed in the Th2R and Th3R regions consistent with balancing selection. The Pfcsp C-terminal sequences had 50 different haplotypes (H_1 to H_50) and only 2% of sequences matched the 3D7 strain haplotype (H_50). Conclusions The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values for parasite populations, consistent with balancing selection for variants within Th2R and Th3R regions. This data is consistent with other studies conducted across Africa and worldwide, which demonstrate low 3D7 haplotypes and little population structure. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
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Affiliation(s)
- Beatus M. Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Misago D. Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Ramadhan Moshi
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Ruth Boniface
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | | | - Rashid Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Deus S. Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Harvard T.H Chan School of Public Health, Boston, MA, USA
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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Sivakumar R, Floyd K, Jessey E, Kim JK, Bayguinov PO, Fitzpatrick JA, Goldfrab D, Jovanovic M, Tripathi A, Djuranovic S, Pavlovic-Djuranovic S. Poly-basic peptides and polymers as new drug candidate against Plasmodium falciparum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.16.558069. [PMID: 37745508 PMCID: PMC10516022 DOI: 10.1101/2023.09.16.558069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Plasmodium falciparum, the malaria-causing parasite, is a leading cause of infection-induced deaths worldwide. The preferred treatment approach is artemisinin-combination therapy, which couples fast-acting artemisinin derivatives with longer-acting drugs like lumefantrine, mefloquine, and amodiaquine. However, the urgency for new treatments has risen due to the parasite's growing resistance to existing therapies. Our study shows that a common characteristic of the P. falciparum proteome - stretches of poly-lysine residues such as those found in proteins related to adhesion and pathogenicity - can serve as an effective peptide treatment for infected erythrocytes. A single dose of these poly-basic peptides can successfully diminish parasitemia in human erythrocytes in vitro with minimal toxicity. The effectiveness of the treatment correlates with the length of the poly-lysine peptide, with 30 lysine peptides supporting the eradication of erythrocytic parasites within 72 hours. PEG-ylation of the poly-lysine peptides or utilizing poly-lysine dendrimers and polymers further increases parasite clearance efficiency and bolsters the stability of these potential new therapeutics. Lastly, our affinity pull-downs and mass-spectrometry identify P. falciparum's outer membrane proteins as likely targets for polybasic peptide medications. Since poly-lysine dendrimers are already FDA-approved for drug delivery, their adaptation as antimalarial drugs presents a promising new therapeutic strategy.
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Affiliation(s)
- Roshan Sivakumar
- Department of Cell Biology and Physiology, Washington University School of Medicine; Missouri, USA
| | - Katherine Floyd
- Department of Cell Biology and Physiology, Washington University School of Medicine; Missouri, USA
| | - Erath Jessey
- Department of Cell Biology and Physiology, Washington University School of Medicine; Missouri, USA
| | - Jenny Kim Kim
- Department of Biological Sciences, Columbia University; New York, New York, USA
| | - Peter O. Bayguinov
- Washington University Center for Cellular Imaging, Washington University School of Medicine; Missouri, USA
- Department of Neuroscience, Washington University School of Medicine; Missouri, USA
| | - James A.J. Fitzpatrick
- Department of Cell Biology and Physiology, Washington University School of Medicine; Missouri, USA
- Washington University Center for Cellular Imaging, Washington University School of Medicine; Missouri, USA
- Department of Neuroscience, Washington University School of Medicine; Missouri, USA
| | - Dennis Goldfrab
- Department of Cell Biology and Physiology, Washington University School of Medicine; Missouri, USA
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University; New York, New York, USA
| | - Abhai Tripathi
- Johns Hopkins Bloomberg School of Public Health; Baltimore, Maryland, USA
| | - Sergej Djuranovic
- Department of Cell Biology and Physiology, Washington University School of Medicine; Missouri, USA
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Chatterjee D, Al Rimon R, Chowdhury UF, Islam MR. A multi-epitope based vaccine against the surface proteins expressed in cyst and trophozoite stages of parasite Entamoeba histolytica. J Immunol Methods 2023; 517:113475. [PMID: 37088358 DOI: 10.1016/j.jim.2023.113475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/12/2023] [Accepted: 04/19/2023] [Indexed: 04/25/2023]
Abstract
Entamoeba histolytica, an anaerobic parasite, infects humans and other primates and causes fatal diseases, such as amebiasis, amebic liver abscesses, and many others. Thousands of people are infected and dying due to the need for a proper protective cure, especially in poor sanitizing regions, such as Latin America, Asia, and Africa. Around 10% of the world population is infected by E. histolytica every year. Consequently, novel preventive approaches are required to eliminate the threats of the parasite. A designed vaccine targeting the exposed proteins that are common between cyst and trophozoite stages of the parasite's life cycle would be an effective way to repress the impact of the parasite. Therefore, an in silico bioinformatics approach was performed to design an effective vaccine targeting surface proteins common between both stages of the parasite's life cycle using B-cell and T-cell epitopes. The epitopes derived from the conserved portions of the proteins and their corresponding isomers specific to the parasite suggested that the vaccine could benefit cross-protection. Furthermore, the three-dimensional structure of the designed vaccine was modelled, refined, and validated using multiple bioinformatics tools. The physiological properties and solubility were also predicted using different algorithmic tools and found to be highly soluble in nature. The vaccine was found interactcted with TLR immune receptors, and the stability was observed via dynamics simulation. Codon optimization and cloning were performed for expression analysis. Immune simulation prediction anticipated significant immune responses with a high IgG and IgM antibodies expression, Th and Tc cells population, B-cell population, memory cells, INF-γ, and IL-2 cytokines. Therefore, the constructed multi-epitope putative vaccine can effectively neutralize the parasite's harmful effects.
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Affiliation(s)
- Dipankor Chatterjee
- Department of Biochemistry and Molecular Biology, University of Dhaka, Bangladesh
| | - Razoan Al Rimon
- Department of Biochemistry and Molecular Biology, University of Dhaka, Bangladesh
| | - Umar Faruq Chowdhury
- Department of Biochemistry and Molecular Biology, University of Dhaka, Bangladesh
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Lyimo BM, Popkin-Hall ZR, Giesbrecht DJ, Mandara CI, Madebe RA, Bakari C, Pereus D, Seth MD, Ngamba RM, Mbwambo RB, MacInnis B, Mbwambo D, Garimo I, Chacky F, Aaron S, Lusasi A, Molteni F, Njau R, Cunningham JA, Lazaro S, Mohamed A, Juliano JJ, Bailey J, Ishengoma DS. Potential Opportunities and Challenges of Deploying Next Generation Sequencing and CRISPR-Cas Systems to Support Diagnostics and Surveillance Towards Malaria Control and Elimination in Africa. Front Cell Infect Microbiol 2022; 12:757844. [PMID: 35909968 PMCID: PMC9326448 DOI: 10.3389/fcimb.2022.757844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/17/2022] [Indexed: 12/02/2022] Open
Abstract
Recent developments in molecular biology and genomics have revolutionized biology and medicine mainly in the developed world. The application of next generation sequencing (NGS) and CRISPR-Cas tools is now poised to support endemic countries in the detection, monitoring and control of endemic diseases and future epidemics, as well as with emerging and re-emerging pathogens. Most low and middle income countries (LMICs) with the highest burden of infectious diseases still largely lack the capacity to generate and perform bioinformatic analysis of genomic data. These countries have also not deployed tools based on CRISPR-Cas technologies. For LMICs including Tanzania, it is critical to focus not only on the process of generation and analysis of data generated using such tools, but also on the utilization of the findings for policy and decision making. Here we discuss the promise and challenges of NGS and CRISPR-Cas in the context of malaria as Africa moves towards malaria elimination. These innovative tools are urgently needed to strengthen the current diagnostic and surveillance systems. We discuss ongoing efforts to deploy these tools for malaria detection and molecular surveillance highlighting potential opportunities presented by these innovative technologies as well as challenges in adopting them. Their deployment will also offer an opportunity to broadly build in-country capacity in pathogen genomics and bioinformatics, and to effectively engage with multiple stakeholders as well as policy makers, overcoming current workforce and infrastructure challenges. Overall, these ongoing initiatives will build the malaria molecular surveillance capacity of African researchers and their institutions, and allow them to generate genomics data and perform bioinformatics analysis in-country in order to provide critical information that will be used for real-time policy and decision-making to support malaria elimination on the continent.
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Affiliation(s)
- Beatus M. Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania
- School of Life Sciences and Bio-Engineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | | | - David J. Giesbrecht
- Pathology and Laboratory Medicine, Center for International Health Research, Brown University, Providence, RI, United States
| | | | - Rashid A. Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Misago D. Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | - Ruth B. Mbwambo
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Bronwyn MacInnis
- Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, United States
- Infectious Disease and Microbiome Program, Broad Institute, Boston, MA, United States
| | | | - Issa Garimo
- National Malaria Control Programme, Dodoma, Tanzania
| | - Frank Chacky
- National Malaria Control Programme, Dodoma, Tanzania
| | | | | | | | - Ritha Njau
- World Health Organization, Country Office, Dar es Salaam, Tanzania
| | - Jane A. Cunningham
- Global Malaria Programme, World Health Organization, Headquarters, Geneva, Switzerland
| | - Samwel Lazaro
- National Malaria Control Programme, Dodoma, Tanzania
| | - Ally Mohamed
- National Malaria Control Programme, Dodoma, Tanzania
| | - Jonathan J. Juliano
- School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Jeffrey A. Bailey
- Pathology and Laboratory Medicine, Center for International Health Research, Brown University, Providence, RI, United States
| | - Deus S. Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, United States
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
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An In Silico Analysis of Malaria Pre-Erythrocytic-Stage Antigens Interpreting Worldwide Genetic Data to Suggest Vaccine Candidate Variants and Epitopes. Microorganisms 2022; 10:microorganisms10061090. [PMID: 35744609 PMCID: PMC9231253 DOI: 10.3390/microorganisms10061090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 02/05/2023] Open
Abstract
Failure to account for genetic diversity of antigens during vaccine design may lead to vaccine escape. To evaluate the vaccine escape potential of antigens used in vaccines currently in development or clinical testing, we surveyed the genetic diversity, measured population differentiation, and performed in silico prediction and analysis of T-cell epitopes of ten such Plasmodium falciparum pre-erythrocytic-stage antigens using whole-genome sequence data from 1010 field isolates. Of these, 699 were collected in Africa (Burkina Faso, Cameroon, Guinea, Kenya, Malawi, Mali, and Tanzania), 69 in South America (Brazil, Colombia, French Guiana, and Peru), 59 in Oceania (Papua New Guinea), and 183 in Asia (Cambodia, Myanmar, and Thailand). Antigens surveyed include cell-traversal protein for ookinetes and sporozoites, circumsporozoite protein, liver-stage antigens 1 and 3, sporozoite surface proteins P36 and P52, sporozoite asparagine-rich protein-1, sporozoite microneme protein essential for cell traversal-2, and upregulated-in-infectious-sporozoite 3 and 4 proteins. The analyses showed that a limited number of these protein variants, when combined, would be representative of worldwide parasite populations. Moreover, predicted T-cell epitopes were identified that could be further explored for immunogenicity and protective efficacy. Findings can inform the rational design of a multivalent malaria vaccine.
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