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Fontoura PS, Macedo EG, Calil PR, Corder RM, Rodrigues PT, Tonini J, Esquivel FD, Ladeia WA, Fernandes ARJ, Johansen IC, Silva MF, Fernandes AOS, Ladeia-Andrade S, Castro MC, Ferreira MU. Changing Clinical Epidemiology of Plasmodium vivax Malaria as Transmission Decreases: Population-Based Prospective Panel Survey in the Brazilian Amazon. J Infect Dis 2024; 229:947-958. [PMID: 38324758 PMCID: PMC11011196 DOI: 10.1093/infdis/jiad456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 10/16/2023] [Indexed: 02/09/2024] Open
Abstract
BACKGROUND Malarial infections are often missed by microscopy, and most parasite carriers are asymptomatic in low-endemicity settings. Whether parasite detectability and its ability to elicit symptoms change as transmission declines remains unclear. METHODS We performed a prospective panel survey with repeated measurements on the same participants over 12 months to investigate whether Plasmodium vivax detectability by microscopy and risk of symptoms upon infection varied during a community-wide larviciding intervention in the Amazon basin of Brazil that markedly reduced vector density. We screened 1096 to 1400 residents in the intervention site for malaria by microscopy and quantitative TaqMan assays at baseline and twice during intervention. RESULTS We found that more P vivax infections than expected from their parasite densities measured by TaqMan assays were missed by microscopy as transmission decreased. At lower transmission, study participants appeared to tolerate higher P vivax loads without developing symptoms. We hypothesize that changes in the ratio between circulating parasites and those that accumulate in the bone marrow and spleen, by avoiding peripheral blood microscopy detection, account for decreased parasite detectability and lower risk of symptoms under low transmission. CONCLUSIONS P vivax infections are more likely to be subpatent and remain asymptomatic as malaria transmission decreases.
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Affiliation(s)
- Pablo S Fontoura
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
- Secretary of Health Surveillance, Ministry of Health, Brasília, Brazil
| | - Evelyn G Macedo
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Priscila R Calil
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Rodrigo M Corder
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
- Divisions of Epidemiology and Biostatistics, Berkeley School of Public Health, University of California
| | - Priscila T Rodrigues
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Juliana Tonini
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Fabiana D Esquivel
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Winni A Ladeia
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | | | - Igor C Johansen
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Marcos F Silva
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | - Amanda O S Fernandes
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
| | | | - Marcia C Castro
- Department of Global Health and Population, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Nova University of Lisbon, Portugal
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Kepple D, Ford CT, Williams J, Abagero B, Li S, Popovici J, Yewhalaw D, Lo E. Comparative transcriptomics reveal differential gene expression among Plasmodium vivax geographical isolates and implications on erythrocyte invasion mechanisms. PLoS Negl Trop Dis 2024; 18:e0011926. [PMID: 38285730 PMCID: PMC10901308 DOI: 10.1371/journal.pntd.0011926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 02/28/2024] [Accepted: 01/19/2024] [Indexed: 01/31/2024] Open
Abstract
The documentation of Plasmodium vivax malaria across Africa especially in regions where Duffy negatives are dominant suggests possibly alternative erythrocyte invasion mechanisms. While the transcriptomes of the Southeast Asian and South American P. vivax are well documented, the gene expression profile of P. vivax in Africa is unclear. In this study, we examined the expression of 4,404 gene transcripts belong to 12 functional groups and 43 erythrocyte binding gene candidates in Ethiopian isolates and compared them with the Cambodian and Brazilian P. vivax transcriptomes. Overall, there were 10-26% differences in the gene expression profile amongst geographical isolates, with the Ethiopian and Cambodian P. vivax being most similar. Majority of the gene transcripts involved in protein transportation, housekeeping, and host interaction were highly transcribed in the Ethiopian isolates. Members of the reticulocyte binding protein PvRBP2a and PvRBP3 expressed six-fold higher than Duffy binding protein PvDBP1 and 60-fold higher than PvEBP/DBP2 in the Ethiopian isolates. Other genes including PvMSP3.8, PvMSP3.9, PvTRAG2, PvTRAG14, and PvTRAG22 also showed relatively high expression. Differential expression patterns were observed among geographical isolates, e.g., PvDBP1 and PvEBP/DBP2 were highly expressed in the Cambodian but not the Brazilian and Ethiopian isolates, whereas PvRBP2a and PvRBP2b showed higher expression in the Ethiopian and Cambodian than the Brazilian isolates. Compared to Pvs25, gametocyte genes including PvAP2-G, PvGAP (female gametocytes), and Pvs47 (male gametocytes) were highly expressed across geographical samples.
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Affiliation(s)
- Daniel Kepple
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Colby T. Ford
- Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina, United States of America
- School of Data Science, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Jonathan Williams
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Beka Abagero
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Shaoyu Li
- Mathematics and Statistics, University of North Carolina, Charlotte, North Carolina, United States of America
| | - Jean Popovici
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Eugenia Lo
- Biological Sciences, University of North Carolina, Charlotte, North Carolina, United States of America
- Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, Pennsylvania, United States of America
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3
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Dash R, Skillman KM, Pereira L, Mascarenhas A, Dass S, Walke J, Almeida A, Fernandes M, Gomes E, White J, Chery-Karschney L, Khandeparkar A, Rathod PK, Duraisingh MT, Kanjee U. Development of a Plasmodium vivax biobank for functional ex vivo assays. Malar J 2023; 22:250. [PMID: 37653486 PMCID: PMC10470152 DOI: 10.1186/s12936-023-04668-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023] Open
Abstract
BACKGROUND Plasmodium vivax is the second most prevalent cause of malaria yet remains challenging to study due to the lack of a continuous in vitro culture system, highlighting the need to establish a biobank of clinical isolates with multiple freezes per sample for use in functional assays. Different methods for cryopreserving parasite isolates were compared and subsequently the most promising one was validated. Enrichment of early- and late-stage parasites and parasite maturation were quantified to facilitate assay planning. METHODS In order to compare cryopreservation protocols, nine clinical P. vivax isolates were frozen with four glycerolyte-based mixtures. Parasite recovery post thaw, post KCl-Percoll enrichment and in short-term in vitro culture was measured via slide microscopy. Enrichment of late-stage parasites by magnetic activated cell sorting (MACS) was measured. Short and long-term storage of parasites at either - 80 °C or liquid nitrogen were also compared. RESULTS Of the four cryopreservation mixtures, one mixture (glycerolyte:serum:RBC at a 2.5:1.5:1 ratio) resulted in improved parasite recovery and statistically significant (P < 0.05) enhancement in parasite survival in short-term in vitro culture. A parasite biobank was subsequently generated using this protocol resulting in a collection of 106 clinical isolates, each with 8 vials. The quality of the biobank was validated by measuring several factors from 47 thaws: the average reduction in parasitaemia post-thaw (25.3%); the average fold enrichment post KCl-Percoll (6.65-fold); and the average percent recovery of parasites (22.0%, measured from 30 isolates). During short-term in vitro culture, robust maturation of ring stage parasites to later stages (> 20% trophozoites, schizonts and gametocytes) was observed in 60.0% of isolates by 48 h. Enrichment of mature parasite stages via MACS showed good reproducibility, with an average of 30.0% post-MACS parasitaemia and an average of 5.30 × 105 parasites/vial. Finally, the effect of storage temperature was tested, and no large impacts from short-term (7 days) or long-term (7-10 years) storage at - 80 °C on parasite recovery, enrichment or viability was observed. CONCLUSIONS Here, an optimized freezing method for P. vivax clinical isolates is demonstrated as a template for the generation and validation of a parasite biobank for use in functional assays.
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Affiliation(s)
- Rashmi Dash
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Kristen M Skillman
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Ligia Pereira
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Anjali Mascarenhas
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Sheena Dass
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Jayashri Walke
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Anvily Almeida
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Mezia Fernandes
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Edwin Gomes
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
| | - John White
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Laura Chery-Karschney
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | | | - Pradipsinh K Rathod
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Usheer Kanjee
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA.
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Kumari S, Sinha A. Culture and transfection: Two major bottlenecks in understanding Plasmodium vivax biology. Front Microbiol 2023; 14:1144453. [PMID: 37082177 PMCID: PMC10110902 DOI: 10.3389/fmicb.2023.1144453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 02/28/2023] [Indexed: 04/07/2023] Open
Abstract
The long term in vitro culture of Plasmodium falciparum was successfully established by Trager and Jensen in 1976; however it largely remains unachieved for P. vivax. The major obstacle associated with Plasmodium vivax in vitro culture is its predilection for invading younger reticulocytes and the complex remodelling of invaded reticulocytes. There are many factors under exploration for this predilection and host–parasite interactions between merozoites and invaded reticulocytes. These include various factors related to parasite, host and environment such as compromised reticulocyte osmotic stability after invasion, abundance of iron in the reticulocytes which makes them favourable for P. vivax growth and propagation and role of a hypoxic environment in P. vivax in vitro growth. P. vivax blood stage transfection represents another major hurdle towards understanding this parasite’s complex biology. Efforts in making this parasite amenable for molecular investigation by genetic modification are limited. Newer approaches in sustaining a longer in vitro culture and thereby help advancing transfection technologies in P. vivax are urgently needed that can be explored to understand the unique biology of this parasite.
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Kepple D, Ford CT, Williams J, Abagero B, Li S, Popovici J, Yewhalaw D, Lo E. Comparative transcriptomics reveal differential gene expression in Plasmodium vivax geographical isolates and implications on erythrocyte invasion mechanisms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528793. [PMID: 36824754 PMCID: PMC9949051 DOI: 10.1101/2023.02.16.528793] [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: 02/18/2023]
Abstract
Plasmodium vivax uses Duffy binding protein (PvDBP1) to bind to the Duffy Antigen-Chemokine Receptor (DARC) to invade human erythrocytes. Individuals who lack DARC expression (Duffy-negative) are thought to be resistance to P. vivax. In recent years, P. vivax malaria is becoming more prevalent in Africa with a portion of these cases detected in Duffy-negatives. Apart from DBP1, members of the reticulocyte binding protein (RBP) and tryptophan-rich antigen (TRAg) families may also play a role in erythrocyte invasion. While the transcriptomes of the Southeast Asian and South American P. vivax are well documented, the gene expression profile of P. vivax in Africa and more specifically the expression level of several erythrocyte binding gene candidates as compared to DBP1 are largely unknown. This paper characterized the first P. vivax transcriptome in Africa and compared with those from the Southeast Asian and South American isolates. The expression of 4,404 gene transcripts belong to 12 functional groups including 43 specific erythrocyte binding gene candidates were examined. Overall, there were 10-26% differences in the gene expression profile amongst the geographical isolates, with the Ethiopian and Cambodian P. vivax being most similar. Majority of the gene transcripts involved in protein transportation, housekeeping, and host interaction were highly transcribed in the Ethiopian P. vivax. Erythrocyte binding genes including PvRBP2a and PvRBP3 expressed six-fold higher than PvDBP1and 60-fold higher than PvEBP/DBP2. Other genes including PvRBP1a, PvMSP3.8, PvMSP3.9, PvTRAG2, PvTRAG14, and PvTRAG22 also showed relatively high expression. Differential expression was observed among geographical isolates, e.g., PvDBP1 and PvEBP/DBP2 were highly expressed in the Cambodian but not the Brazilian and Ethiopian isolates, whereas PvRBP2a and PvRBP2b showed higher expression in the Ethiopian and Cambodian than the Brazilian isolates. Compared to Pvs25, the standard biomarker for detecting female gametocytes, PvAP2-G (PVP01_1440800), GAP (PVP01_1403000), and Pvs47 (PVP01_1208000) were highly expressed across geographical samples. These findings provide an important baseline for future comparisons of P. vivax transcriptomes from Duffy-negative infections and highlight potential biomarkers for improved gametocyte detection.
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Affiliation(s)
- Daniel Kepple
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Colby T. Ford
- Bioinformatics and Genomics, University of North Carolina, Charlotte, NC 28223, USA
- School of Data Science, University of North Carolina, Charlotte, NC 28223, USA
| | - Jonathan Williams
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Beka Abagero
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
| | - Shaoyu Li
- Mathematics and Statistics, University of North Carolina, Charlotte, NC 28223, USA
| | - Jean Popovici
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Eugenia Lo
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA
- School of Data Science, University of North Carolina, Charlotte, NC 28223, USA
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6
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Keroack CD, Duraisingh MT. Molecular mechanisms of cellular quiescence in apicomplexan parasites. Curr Opin Microbiol 2022; 70:102223. [PMID: 36274498 DOI: 10.1016/j.mib.2022.102223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 01/25/2023]
Abstract
Quiescence is a reversible nonproliferative cellular state that allows organisms to persist through unfavorable conditions. Quiescence can be stimulated by a wide range of external or intrinsic factors. Cells undergo a coordinated molecular program to enter and exit from the quiescent state, which is governed by signaling, transcriptional and translational changes, epigenetic mechanisms, metabolic switches, and changes in cellular architecture. These mechanisms have been extensively studied in model organisms, and a growing number of studies have identified conserved mechanisms in apicomplexan parasites. Quiescence in the context of a parasitic infection has significant clinical impact: quiescent forms may underlie treatment failures, relapsing infections, and stress tolerance. Here, we review the latest understanding of quiescence in apicomplexa, synthesizing these studies to highlight conserved mechanisms, and identifying technologies to assist in further characterization of quiescence. Understanding conserved mechanisms of quiescence in apicomplexans will provide avenues for transmission prevention and radical cure of infections.
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De Meulenaere K, Prajapati SK, Villasis E, Cuypers B, Kattenberg JH, Kasian B, Laman M, Robinson LJ, Gamboa D, Laukens K, Rosanas-Urgell A. Band 3–mediated Plasmodium vivax invasion is associated with transcriptional variation in PvTRAg genes. Front Cell Infect Microbiol 2022; 12:1011692. [PMID: 36250048 PMCID: PMC9563252 DOI: 10.3389/fcimb.2022.1011692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
The Plasmodium vivax reticulocyte invasion process is still poorly understood, with only a few receptor-ligand interactions identified to date. Individuals with the Southeast Asian ovalocytosis (SAO) phenotype have a deletion in the band 3 protein on the surface of erythrocytes, and are reported to have a lower incidence of clinical P. vivax malaria. Based on this observation, band 3 has been put forward as a receptor for P. vivax invasion, although direct proof is still lacking. In this study, we combined functional ex vivo invasion assays and transcriptome sequencing to uncover a band 3–mediated invasion pathway in P. vivax and potential band 3 ligands. Invasion by P. vivax field isolates was 67%-71% lower in SAO reticulocytes compared with non-SAO reticulocytes. Reticulocyte invasion was decreased by 40% and 27%-31% when blocking with an anti-band 3 polyclonal antibody and a PvTRAg38 peptide, respectively. To identify new band 3 receptor candidates, we mRNA-sequenced schizont-stage isolates used in the invasion assays, and observed high transcriptional variability in multigene and invasion-related families. Transcriptomes of isolates with low or high dependency on band 3 for invasion were compared by differential expression analysis, which produced a list of band 3 ligand candidates with high representation of PvTRAg genes. Our ex vivo invasion assays have demonstrated that band 3 is a P. vivax invasion receptor and confirm previous in vitro studies showing binding between PvTRAg38 and band 3, although the lower and variable inhibition levels observed suggest the involvement of other ligands. By coupling transcriptomes and invasion phenotypes from the same isolates, we identified a list of band 3 ligand candidates, of which the overrepresented PvTRAg genes are the most promising for future research.
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Affiliation(s)
- Katlijn De Meulenaere
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
- *Correspondence: Anna Rosanas-Urgell, ; Katlijn De Meulenaere,
| | - Surendra Kumar Prajapati
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Elizabeth Villasis
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Bart Cuypers
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | | | - Bernadine Kasian
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Moses Laman
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Leanne J. Robinson
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
- Health Security and Disease Elimination, Burnet Institute, Melbourne, VIC, Australia
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Kris Laukens
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- *Correspondence: Anna Rosanas-Urgell, ; Katlijn De Meulenaere,
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8
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Pessoa RC, Oliveira-Pessoa GF, Souza BKA, Sampaio VS, Pinto ALCB, Barboza LL, Mouta GS, Silva EL, Melo GC, Monteiro WM, Silva-Filho JH, Lacerda MVG, Baía-da-Silva DC. Impact of Plasmodium vivax malaria on executive and cognitive functions in elderlies in the Brazilian Amazon. Sci Rep 2022; 12:10361. [PMID: 35725784 PMCID: PMC9208538 DOI: 10.1038/s41598-022-14175-0] [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: 12/17/2021] [Accepted: 05/16/2022] [Indexed: 11/09/2022] Open
Abstract
The exact path leading to cognitive impairment that goes beyond malaria is unclear, but it appears to be the result of interactive factors. Time of exposure to disease and recurrences are potentially major determinant variables. Cognitive impairment is described mainly in children, rarely in adults. The disease in high endemic areas usually does not affect elderlies, because of acquired immunity over time. However, this population is relatively more frequently sick in lower endemic areas, such as in the Amazon. This study assessed the effect of Plasmodium vivax malaria on the executive and cognitive functions of elderlies, in the Brazilian Amazon. A cohort study was conducted to evaluate executive and cognitive functions one week (T0), two months (T2) and eight months (T8) after the malaria episode. Mini-Mental State Examination (MMSE), Beck Depression Inventory II (BDI-II), Clock Drawing Test (CDT), Wechsler adult intelligence scale (WAIS-III), and Wisconsin Card Sorting Test (WCST) were used to assess executive and cognitive functions. One hundred-forty elderlies were enrolled (70 with P. vivax malaria and 70 without malaria). P. vivax malaria was associated with impairment of the executive and cognitive functions in elderlies for up to 8 months after acute P. vivax malaria. Prior history of malaria, recurrences and higher parasitemia were independently associated with various surrogates of executive and cognitive impairment. With the increase in life expectancy, elderlies living in malaria endemic areas will deserve more attention from health authorities, to guarantee improvement of their quality of life in the tropics.
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Affiliation(s)
- Rockson C Pessoa
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | | | - Brenda K A Souza
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Vanderson S Sampaio
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz, Manaus, Brazil
- Fundação de Vigilância em Saúde do Amazonas, Manaus, Brazil
| | - André Luiz C B Pinto
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil
| | - Larissa L Barboza
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Gabriel S Mouta
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Emanuelle Lira Silva
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil
| | - Gisely C Melo
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil
| | - Wuelton M Monteiro
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil
| | | | - Marcus V G Lacerda
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil.
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil.
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz, Manaus, Brazil.
| | - Djane Clarys Baía-da-Silva
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil
- Instituto de Pesquisa Clínica Carlos Borborema, Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Av Pedro Teixeira, 25, Manaus, Amazonas, 69040-000, Brazil
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz, Manaus, Brazil
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9
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Bantuchai S, Imad H, Nguitragool W. Plasmodium vivax gametocytes and transmission. Parasitol Int 2021; 87:102497. [PMID: 34748969 DOI: 10.1016/j.parint.2021.102497] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/14/2021] [Accepted: 10/30/2021] [Indexed: 10/19/2022]
Abstract
Malaria elimination means cessation of parasite transmission. At present, the declining malaria incidence in many countries has made elimination a feasible goal. Transmission control has thus been placed at the center of the national malaria control programs. The efficient transmission of Plasmodium vivax from humans to mosquitoes is a key factor that helps perpetuate malaria in endemic areas. A better understanding of transmission is crucial to the success of elimination efforts. Biological delineation of the parasite transmission process is important for identifying and prioritizing new targets of intervention. Identification of the infectious parasite reservoir in the community is key to devising an effective elimination strategy. Here we describe the fundamental characteristics of P. vivax gametocytes - the dynamics of their production, longevity, and the relationship with the total parasitemia - as well as recent advances in the molecular understanding of parasite sexual development. In relation to malaria elimination, factors influencing the human infectivity and the current evidence for a role of asymptomatic carriers in transmission are presented.
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Affiliation(s)
- Sirasate Bantuchai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| | - Hisham Imad
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| | - Wang Nguitragool
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand; Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
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10
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Sutrave S, Richter MH. The Truman Show for protozoan parasites: A review of in vitro cultivation platforms. PLoS Negl Trop Dis 2021; 15:e0009668. [PMID: 34437538 PMCID: PMC8389406 DOI: 10.1371/journal.pntd.0009668] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Protozoan parasites are responsible for severe disease and suffering in humans worldwide. Apart from disease transmission via insect vectors and contaminated soil, food, or water, transmission may occur congenitally or by way of blood transfusion and organ transplantation. Several recent outbreaks associated with fresh produce and potable water emphasize the need for vigilance and monitoring of protozoan parasites that cause severe disease in humans globally. Apart from the tropical parasite Plasmodium spp., other protozoa causing debilitating and fatal diseases such as Trypanosoma spp. and Naegleria fowleri need to be studied in more detail. Climate change and socioeconomic issues such as migration continue to be major drivers for the spread of these neglected tropical diseases beyond endemic zones. Due to the complex life cycles of protozoa involving multiple hosts, vectors, and stringent growth conditions, studying these parasites has been challenging. While in vivo models may provide insights into host–parasite interaction, the ethical aspects of laboratory animal use and the challenge of ready availability of parasite life stages underline the need for in vitro models as valid alternatives for culturing and maintaining protozoan parasites. To our knowledge, this review is the first of its kind to highlight available in vitro models for protozoa causing highly infectious diseases. In recent years, several research efforts using new technologies such as 3D organoid and spheroid systems for protozoan parasites have been introduced that provide valuable tools to advance complex culturing models and offer new opportunities toward the advancement of parasite in vitro studies. In vitro models aid scientists and healthcare providers in gaining insights into parasite infection biology, ultimately enabling the use of novel strategies for preventing and treating these diseases. In light of the far-reaching social and economic repercussions of communicable, zoonotic parasitic diseases on human health, it is imperative to continue to strive toward developing in vitro models for in-depth scrutiny and understanding of pathogenicity, as well as for innovations toward combating these infections. This review, to our knowledge, is the first to offer a qualitative summary of the existing models for culturing protozoan parasites with major relevance to human health in vitro. The present work aims to provide a reference guide on the current state of in vitro culture of these protozoan parasites and offers a foundation to facilitate exchange of expertise among researchers, clinicians, and healthcare workers. This comprehensive review would aid in enabling discussions on new intervention approaches to fill in the knowledge gaps in the field of parasitic diseases affecting the global population.
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Affiliation(s)
- Smita Sutrave
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Berlin, Germany
| | - Martin Heinrich Richter
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Berlin, Germany
- * E-mail:
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11
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Buyon LE, Elsworth B, Duraisingh MT. The molecular basis of antimalarial drug resistance in Plasmodium vivax. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2021; 16:23-37. [PMID: 33957488 PMCID: PMC8113647 DOI: 10.1016/j.ijpddr.2021.04.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/31/2021] [Accepted: 04/08/2021] [Indexed: 01/07/2023]
Abstract
Plasmodium vivax is the most geographically widespread cause of human malaria and is responsible for the majority of cases outside of the African continent. While great progress has been made towards eliminating human malaria, drug resistant parasite strains pose a threat towards continued progress. Resistance has arisen to multiple antimalarials in P. vivax, including to chloroquine, which is currently the first line therapy for P. vivax in most regions. Despite its importance, an understanding of the molecular mechanisms of drug resistance in this species remains elusive, in large part due to the complex biology of P. vivax and the lack of in vitro culture. In this review, we will cover the extent and challenges of measuring clinical and in vitro drug resistance in P. vivax. We will consider the roles of candidate drug resistance genes. We will highlight the development of molecular approaches for studying P. vivax biology that provide the opportunity to validate the role of putative drug resistance mutations as well as identify novel mechanisms of drug resistance in this understudied parasite. Validated molecular determinants and markers of drug resistance are essential for the rapid and cost-effective monitoring of drug resistance in P. vivax, and will be useful for optimizing drug regimens and for informing drug policy in control and elimination settings. Drug resistance is emerging in Plasmodium vivax, an important cause of malaria. The complex biology of P. vivax and the limited range of research tools make it difficult to identify drug resistance. The molecular mechanisms of drug resistance in P. vivax remain elusive. This review highlights the extent of drug resistance, the putative mechanisms of resistance and new technologies for the study of P. vivax drug resistance.
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Affiliation(s)
- Lucas E Buyon
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02115, MA, USA
| | - Brendan Elsworth
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02115, MA, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02115, MA, USA.
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12
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Clark MA, Kanjee U, Rangel GW, Chery L, Mascarenhas A, Gomes E, Rathod PK, Brugnara C, Ferreira MU, Duraisingh MT. Plasmodium vivax infection compromises reticulocyte stability. Nat Commun 2021; 12:1629. [PMID: 33712609 PMCID: PMC7955053 DOI: 10.1038/s41467-021-21886-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 02/17/2021] [Indexed: 12/21/2022] Open
Abstract
The structural integrity of the host red blood cell (RBC) is crucial for propagation of Plasmodium spp. during the disease-causing blood stage of malaria infection. To assess the stability of Plasmodium vivax-infected reticulocytes, we developed a flow cytometry-based assay to measure osmotic stability within characteristically heterogeneous reticulocyte and P. vivax-infected samples. We find that erythroid osmotic stability decreases during erythropoiesis and reticulocyte maturation. Of enucleated RBCs, young reticulocytes which are preferentially infected by P. vivax, are the most osmotically stable. P. vivax infection however decreases reticulocyte stability to levels close to those of RBC disorders that cause hemolytic anemia, and to a significantly greater degree than P. falciparum destabilizes normocytes. Finally, we find that P. vivax new permeability pathways contribute to the decreased osmotic stability of infected-reticulocytes. These results reveal a vulnerability of P. vivax-infected reticulocytes that could be manipulated to allow in vitro culture and develop novel therapeutics. During Plasmodium intra-erythrocytic developmental, parasites compromise the structural integrity of host red-blood cells. Here, Clark et al. develop a flow cytometric osmotic stability assay to show that P. vivax infection destabilizes host reticulocytes, which are less stable than P. falciparum-infected normocytes.
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Affiliation(s)
- Martha A Clark
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Usheer Kanjee
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Gabriel W Rangel
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Laura Chery
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Anjali Mascarenhas
- Malaria Evolution in South Asia (MESA)-International Centers of Excellence in Malaria Research (ICEMR), Goa Medical College, Bambolim, Goa, India
| | - Edwin Gomes
- Malaria Evolution in South Asia (MESA)-International Centers of Excellence in Malaria Research (ICEMR), Goa Medical College, Bambolim, Goa, India
| | | | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
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13
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Bourgard C, Lopes SCP, Lacerda MVG, Albrecht L, Costa FTM. A suitable RNA preparation methodology for whole transcriptome shotgun sequencing harvested from Plasmodium vivax-infected patients. Sci Rep 2021; 11:5089. [PMID: 33658571 PMCID: PMC7930272 DOI: 10.1038/s41598-021-84607-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 01/06/2021] [Indexed: 12/03/2022] Open
Abstract
Plasmodium vivax is a world-threatening human malaria parasite, whose biology remains elusive. The unavailability of in vitro culture, and the difficulties in getting a high number of pure parasites makes RNA isolation in quantity and quality a challenge. Here, a methodological outline for RNA-seq from P. vivax isolates with low parasitemia is presented, combining parasite maturation and enrichment with efficient RNA extraction, yielding ~ 100 pg.µL−1 of RNA, suitable for SMART-Seq Ultra-Low Input RNA library and Illumina sequencing. Unbiased coding transcriptome of ~ 4 M reads was achieved for four patient isolates with ~ 51% of transcripts mapped to the P. vivax P01 reference genome, presenting heterogeneous profiles of expression among individual isolates. Amongst the most transcribed genes in all isolates, a parasite-staged mixed repertoire of conserved parasite metabolic, membrane and exported proteins was observed. Still, a quarter of transcribed genes remain functionally uncharacterized. In parallel, a P. falciparum Brazilian isolate was also analyzed and 57% of its transcripts mapped against IT genome. Comparison of transcriptomes of the two species revealed a common trophozoite-staged expression profile, with several homologous genes being expressed. Collectively, these results will positively impact vivax research improving knowledge of P. vivax biology.
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Affiliation(s)
- Catarina Bourgard
- Laboratory of Tropical Diseases, Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Stefanie C P Lopes
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz-Fiocruz, Manaus, AM, Brazil.,Fundação de Medicina Tropical Dr. Heitor Vieira Dourado-FMT-HVD, Gerência de Malária, Manaus, AM, Brazil
| | - Marcus V G Lacerda
- Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz-Fiocruz, Manaus, AM, Brazil.,Fundação de Medicina Tropical Dr. Heitor Vieira Dourado-FMT-HVD, Gerência de Malária, Manaus, AM, Brazil
| | - Letusa Albrecht
- Laboratory of Tropical Diseases, Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil. .,Instituto Carlos Chagas, Fundação Oswaldo Cruz-Fiocruz, Curitiba, PR, Brazil.
| | - Fabio T M Costa
- Laboratory of Tropical Diseases, Prof. Dr. Luiz Jacintho da Silva, Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas-UNICAMP, Campinas, SP, Brazil.
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14
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Siegel SV, Chappell L, Hostetler JB, Amaratunga C, Suon S, Böhme U, Berriman M, Fairhurst RM, Rayner JC. Analysis of Plasmodium vivax schizont transcriptomes from field isolates reveals heterogeneity of expression of genes involved in host-parasite interactions. Sci Rep 2020; 10:16667. [PMID: 33028892 PMCID: PMC7541449 DOI: 10.1038/s41598-020-73562-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/18/2020] [Indexed: 11/28/2022] Open
Abstract
Plasmodium vivax gene regulation remains difficult to study due to the lack of a robust in vitro culture method, low parasite densities in peripheral circulation and asynchronous parasite development. We adapted an RNA-seq protocol “DAFT-seq” to sequence the transcriptome of four P. vivax field isolates that were cultured for a short period ex vivo before using a density gradient for schizont enrichment. Transcription was detected from 78% of the PvP01 reference genome, despite being schizont-enriched samples. This extensive data was used to define thousands of 5′ and 3′ untranslated regions, some of which overlapped with neighbouring transcripts, and to improve the gene models of 352 genes, including identifying 20 novel gene transcripts. This dataset has also significantly increased the known amount of heterogeneity between P. vivax schizont transcriptomes from individual patients. The majority of genes found to be differentially expressed between the isolates lack Plasmodium falciparum homologs and are predicted to be involved in host-parasite interactions, with an enrichment in reticulocyte binding proteins, merozoite surface proteins and exported proteins with unknown function. An improved understanding of the diversity within P. vivax transcriptomes will be essential for the prioritisation of novel vaccine targets.
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Affiliation(s)
- Sasha V Siegel
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Lia Chappell
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Jessica B Hostetler
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.,Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.,National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Chanaki Amaratunga
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bankgok, Thailand.,Center for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Seila Suon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Ulrike Böhme
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Matthew Berriman
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.,AstraZeneca, Gaithersburg, MD, 20878, USA
| | - Julian C Rayner
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK. .,Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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Obaldía N, Nuñez M. On the survival of 48 h Plasmodium vivax Aotus monkey-derived ex vivo cultures: the role of leucocytes filtration and chemically defined lipid concentrate media supplementation. Malar J 2020; 19:278. [PMID: 32746814 PMCID: PMC7398384 DOI: 10.1186/s12936-020-03348-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/25/2020] [Indexed: 11/10/2022] Open
Abstract
Background Filtration of leukocytes (WBCs) is a standard practice of malaria ex vivo cultures. To date, few studies have considered the effect of filtration or the lack thereof on the survival of Plasmodium vivax ex vivo cultures through one cycle of maturation. This study investigates the effect of WBC filtration and culture media supplementation on the survival of 48–72 h ex vivo cultures. Methods Using parasitaemia density, the study compares the survival of Plasmodipur® filtered, filter-retained or washed ex vivo cultures, maintained with McCoy’s5A medium supplemented with 25% serum alone or 20% in combination with 5% chemically defined lipid concentrate (CDLC), and in washed ex vivo cultures plus GlutaMAX™, benchmarked against IMDM™ or AIM-V™ media; also, assessed the survival of ex vivo cultures co-cultivated with human red blood cells (hRBCs). Results After 48 h of incubation a statistically significant difference was detected in the survival proportions of filtered and the filter-retained ex vivo cultures supplemented with serum plus CDLC (p = 0.0255), but not with serum alone (p = 0.1646). To corroborate these finding, parasitaemias of washed ex vivo cultures maintained with McCoy’s5A complete medium were benchmarked against IMDM™ or AIM-V™ media; again, a statistically significant difference was detected in the cultures supplemented with CDLC and GlutaMAX™ (p = 0.03), but not when supplemented with either alone; revealing a pattern of McCoy’s5A medium supplementation for Aotus-derived P. vivax cultures as follows: serum < serum + GlutaMAX™ < serum + CDLC < serum + CDLC + GlutaMAX™; confirming a key role of CDLC in combination with GlutaMAX™ in the enhanced survival observed. Lastly, results showed that co-cultivation with malaria-naïve hRBCs improved the survival of ex vivo cultures. Conclusions This study demonstrates that WBC filtration is not essential for the survival of P. vivax ex vivo cultures. It also demonstrates that McCoy’s5A complete medium improves the survival of Aotus-derived P. vivax ex vivo cultures, with no significant difference in survival compared to IMDM and AIM-V media. Finally, the study demonstrates that co-cultivation with hRBCs enhances the survival of ex vivo cultures. These findings are expected to help optimize seeding material for long-term P. vivax in vitro culture.
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Affiliation(s)
- Nicanor Obaldía
- Center for the Evaluation of Antimalarial Drugs and Vaccines, Tropical Medicine Research/Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama city, Panama. .,Center for Global Health & Infectious Diseases Research, Department of Global Health, University of South Florida, Tampa, FL, USA. .,Department of Immunology and Infectious Diseases, Harvard, T.H. Chan School of Public Health, Boston, MA, USA.
| | - Marlon Nuñez
- Center for the Evaluation of Antimalarial Drugs and Vaccines, Tropical Medicine Research/Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama city, Panama
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