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Nema S, Nitika N. Monoclonal antibody: future of malaria control and prevention. Trans R Soc Trop Med Hyg 2023; 117:673-674. [PMID: 37093779 DOI: 10.1093/trstmh/trad027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/24/2023] [Accepted: 04/12/2023] [Indexed: 04/25/2023] Open
Abstract
Monoclonal antibodies (mAbs) are extremely specialized proteins that are cloned from B cells and bind to pathogen epitopes. There are currently no known prophylactic immune-based strategies or efficient, widespread treatments to stop the spread of malaria. In order to lower the prevalence of malaria and its associated mortality, we need mAbs that are capable of offering immediate passive protection against the disease. mAbs have become more crucial in the treatment or prevention of several other infectious diseases. Recently, mAb development for malaria prevention and control has greatly evolved and widespread use in public health settings is now a possibility.
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Affiliation(s)
- Shrikant Nema
- Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, Sector 8, Dwarka 110077, New Delhi, India
| | - Nitika Nitika
- Parasite-Host Biology Group, ICMR-National Institute of Malaria Research, Sector 8, Dwarka 110077, New Delhi, India
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2
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Kumar P, Kumar P, Mandal D, Velayutham R. The emerging role of Deubiquitinases (DUBs) in parasites: A foresight review. Front Cell Infect Microbiol 2022; 12:985178. [PMID: 36237424 PMCID: PMC9552668 DOI: 10.3389/fcimb.2022.985178] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022] Open
Abstract
Before the discovery of the proteasome complex, the lysosomes with acidic proteases and caspases in apoptotic pathways were thought to be the only pathways for the degradation of damaged, unfolded, and aged proteins. However, the discovery of 26S and 20S proteasome complexes in eukaryotes and microbes, respectively, established that the degradation of most proteins is a highly regulated ATP-dependent pathway that is significantly conserved across each domain of life. The proteasome is part of the ubiquitin-proteasome system (UPS), where the covalent tagging of a small molecule called ubiquitin (Ub) on the proteins marks its proteasomal degradation. The type and chain length of ubiquitination further determine whether a protein is designated for further roles in multi-cellular processes like DNA repair, trafficking, signal transduction, etc., or whether it will be degraded by the proteasome to recycle the peptides and amino acids. Deubiquitination, on the contrary, is the removal of ubiquitin from its substrate molecule or the conversion of polyubiquitin chains into monoubiquitin as a precursor to ubiquitin. Therefore, deubiquitylating enzymes (DUBs) can maintain the dynamic state of cellular ubiquitination by releasing conjugated ubiquitin from proteins and controlling many cellular pathways that are essential for their survival. Many DUBs are well characterized in the human system with potential drug targets in different cancers. Although, proteasome complex and UPS of parasites, like plasmodium and leishmania, were recently coined as multi-stage drug targets the role of DUBs is completely unexplored even though structural domains and functions of many of these parasite DUBs are conserved having high similarity even with its eukaryotic counterpart. This review summarizes the identification & characterization of different parasite DUBs based on in silico and a few functional studies among different phylogenetic classes of parasites including Metazoan (Schistosoma, Trichinella), Apicomplexan protozoans (Plasmodium, Toxoplasma, Eimeria, Cryptosporidium), Kinetoplastidie (Leishmania, Trypanosoma) and Microsporidia (Nosema). The identification of different homologs of parasite DUBs with structurally similar domains with eukaryotes, and the role of these DUBs alone or in combination with the 20S proteosome complex in regulating the parasite survival/death is further elaborated. We propose that small molecules/inhibitors of human DUBs can be potential antiparasitic agents due to their significant structural conservation.
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Affiliation(s)
- Prakash Kumar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, India
| | - Pawan Kumar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, India
| | - Debabrata Mandal
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, India
- *Correspondence: Ravichandiran Velayutham, ; Debabrata Mandal,
| | - Ravichandiran Velayutham
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Hajipur, India
- National Institute of Pharmaceutical Education and Research, Kolkata, India
- *Correspondence: Ravichandiran Velayutham, ; Debabrata Mandal,
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3
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Stochastic expression of invasion genes in Plasmodium falciparum schizonts. Nat Commun 2022; 13:3004. [PMID: 35637187 PMCID: PMC9151791 DOI: 10.1038/s41467-022-30605-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/22/2022] [Indexed: 12/15/2022] Open
Abstract
Genetically identical cells are known to exhibit differential phenotypes in the same environmental conditions. These phenotypic variants are linked to transcriptional stochasticity and have been shown to contribute towards adaptive flexibility of a wide range of unicellular organisms. Here, we investigate transcriptional heterogeneity and stochastic gene expression in Plasmodium falciparum by performing the quasilinear multiple annealing and looping based amplification cycles (MALBAC) based amplification and single cell RNA sequencing of blood stage schizonts. Our data reveals significant transcriptional variations in the schizont stage with a distinct group of highly variable invasion gene transcripts being identified. Moreover, the data reflects several diversification processes including putative developmental “checkpoint”; transcriptomically distinct parasite sub-populations and transcriptional switches in variable gene families (var, rifin, phist). Most of these features of transcriptional variability are preserved in isogenic parasite cell populations (albeit with a lesser amplitude) suggesting a role of epigenetic factors in cell-to-cell transcriptional variations in human malaria parasites. Lastly, we apply quantitative RT-PCR and RNA-FISH approach and confirm stochastic expression of key invasion genes, such as, msp1, msp3, msp7, eba181 and ama1 which represent prime candidates for invasion-blocking vaccines. Genetically identical cells can be phenotypically diverse to allow adaptive flexibility in a given environment. This phenotypic diversity is driven by epigenetic and transcriptional variability. Here, Tripathi et al. perform scRNA-seq of isogenic and non-isogenic Plasmodium falciparum schizont populations to explore transcriptional heterogeneity and stochastic gene expression during the course of development.
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4
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Zaric M, Marini A, Nielsen CM, Gupta G, Mekhaiel D, Pham TP, Elias SC, Taylor IJ, de Graaf H, Payne RO, Li Y, Silk SE, Williams C, Hill AVS, Long CA, Miura K, Biswas S. Poor CD4 + T Cell Immunogenicity Limits Humoral Immunity to P. falciparum Transmission-Blocking Candidate Pfs25 in Humans. Front Immunol 2021; 12:732667. [PMID: 34659219 PMCID: PMC8515144 DOI: 10.3389/fimmu.2021.732667] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum transmission-blocking vaccines (TBVs) targeting the Pfs25 antigen have shown promise in mice but the same efficacy has never been achieved in humans. We have previously published pre-clinical data related to a TBV candidate Pfs25-IMX313 encoded in viral vectors which was very promising and hence progressed to human clinical trials. The results from the clinical trial of this vaccine were very modest. Here we unravel why, contrary to mice, this vaccine has failed to induce robust antibody (Ab) titres in humans to elicit transmission-blocking activity. We examined Pfs25-specific B cell and T follicular helper (Tfh) cell responses in mice and humans after vaccination with Pfs25-IMX313 encoded by replication-deficient chimpanzee adenovirus serotype 63 (ChAd63) and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA) delivered in the heterologous prime-boost regimen via intramuscular route. We found that after vaccination, the Pfs25-IMX313 was immunologically suboptimal in humans compared to mice in terms of serum Ab production and antigen-specific B, CD4+ and Tfh cell responses. We identified that the key determinant for the poor anti-Pfs25 Ab formation in humans was the lack of CD4+ T cell recognition of Pfs25-IMX313 derived peptide epitopes. This is supported by correlations established between the ratio of proliferated antigen-specific CD4+/Tfh-like T cells, CXCL13 sera levels, and the corresponding numbers of circulating Pfs25-specific memory B cells, that consequently reflected on antigen-specific IgG sera levels. These correlations can inform the design of next-generation Pfs25-based vaccines for robust and durable blocking of malaria transmission.
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Affiliation(s)
- Marija Zaric
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Arianna Marini
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Carolyn M Nielsen
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Gaurav Gupta
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - David Mekhaiel
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Thao P Pham
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, United States
| | - Sean C Elias
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Iona J Taylor
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Hans de Graaf
- NIHR Clinical Research Facility, University Hospital Southampton NHS Foundation Trust and Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Ruth O Payne
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Yuanyuan Li
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Sarah E Silk
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Chris Williams
- 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
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, United States
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, United States
| | - Sumi Biswas
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
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Arshad AR, Bashir I, Ijaz F, Loh N, Shukla S, Rehman UU, Aftab RK. Is COVID-19 Fatality Rate Associated with Malaria Endemicity? Discoveries (Craiova) 2020; 8:e120. [PMID: 33365386 PMCID: PMC7749783 DOI: 10.15190/d.2020.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
COVID-19 (coronavirus disease 2019) is a disease caused by the coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). COVID-19 has yielded many reported complications and unusual observations. In this article, we have reviewed one such observation: an association between malaria endemicity and reduced reported COVID-19 fatality. Malaria-endemic regions have a significantly lower reported COVID-19 fatality rate as compared to regions where malaria is non-endemic. Statistical analyses show that there is a strong negative correlation between the reported SARS-CoV-2 fatality and endemicity of malaria. In this review, we have discussed the potential role of CD-147, and potential malaria-induced immunity and polymorphisms in COVID-19 patients. Noteworthy, the results may also be due to underreported cases or due to the economic, political, and environmental differences between the malaria endemic and non-endemic countries. The study of this potential relationship might be of great help in COVID-19 therapy and prevention.
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Affiliation(s)
- Abdul Rehman Arshad
- CMH Lahore Medical College and Institute of Dentistry (NUMS), Lahore, Pakistan
| | - Imtiaz Bashir
- CMH Lahore Medical College and Institute of Dentistry (NUMS), Lahore, Pakistan
| | - Farhat Ijaz
- CMH Lahore Medical College and Institute of Dentistry (NUMS), Lahore, Pakistan
| | - Nicholas Loh
- Flinders University, College of Medicine and Public Health. Adelaide, SA, Australia
| | - Suraj Shukla
- Flinders University, College of Medicine and Public Health. Adelaide, SA, Australia
| | - Ubaid Ur Rehman
- Flinders University, College of Medicine and Public Health. Adelaide, SA, Australia
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6
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Tam DNH, Tawfik GM, El-Qushayri AE, Mehyar GM, Istanbuly S, Karimzadeh S, Tu VL, Tiwari R, Van Dat T, Nguyen PTV, Hirayama K, Huy NT. Correlation between anti-malarial and anti-haemozoin activities of anti-malarial compounds. Malar J 2020; 19:298. [PMID: 32825818 PMCID: PMC7441662 DOI: 10.1186/s12936-020-03370-x] [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: 04/27/2020] [Accepted: 08/10/2020] [Indexed: 11/10/2022] Open
Abstract
Background Despite noticeable improvement in anti-malarial treatment, rapid growth of resistant malaria strains points out the need for continuous development of novel anti-malarials to fight the disastrous infection. Haemozoin is considered as a novel inhibitory pathway for new anti-malarial drugs, therefore, this study aimed to systematically review all articles investigating the correlation between anti-malarial and anti-haemozoin activities of anti-malarial compounds. Methods A literature search was conducted on 22 October 2017 in eight databases for relevant in vitro articles reporting the correlation between anti-malarial and anti-haemozoin of anti-malarial compounds, based on the constructed search terms and inclusion criteria. ToxRtool was used to assess quality of each study. Results A total of ten articles were included in the review. In vitro anti-malarial and anti-haemozoin activity had a good correlation for quinolines for sensitive strains (R2 ranging from 0.66 to 0.95) and xanthones (Spearman ρ = 0.886). However, these correlations were reached after removing some compounds which had non-detectable anti-malarial or anti-haemozoin effects. Other structures (acridines, pyrolidines) showed negligible correlation with Spearman ρ ranging from 0.095 to 0.381 for acridines, and r varying from 0.54 to 0.62 for pyrolidines. Some good correlations were only shown in a logarithmic manner or when the anti-malarial activity was normalized. Conclusion The results raised a relative relationship between anti-haemozoin and in vitro anti-malarial activities. Some studies reported compounds that were effective in the inhibition of haemozoin formation, but failed to inhibit the parasite survival and vice versa. The correlation results in these studies were calculated after these compounds were removed from their analysis. The ability of anti-malarial compounds to accumulate inside the reaction site might strengthen their anti-malarial activity.
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Affiliation(s)
- Dao Ngoc Hien Tam
- Asia Shine Trading & Service CO. LTD., Ho Chi Minh City, Vietnam.,Online Research Club, Nagasaki, Japan
| | - Gehad Mohamed Tawfik
- Online Research Club, Nagasaki, Japan.,Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Amr Ehab El-Qushayri
- Online Research Club, Nagasaki, Japan.,Faculty of Medicine, Minia University, Minia, 61519, Egypt
| | - Ghaleb Muhammad Mehyar
- Online Research Club, Nagasaki, Japan.,Southwest Physicians Associates S.C., 2955 W 95th St, Evergreen Park, IL, 60805, USA
| | - Sedralmontaha Istanbuly
- Online Research Club, Nagasaki, Japan.,Faculty of Medicine, University of Aleppo, Aleppo, Syrian Arab Republic
| | - Sedighe Karimzadeh
- Online Research Club, Nagasaki, Japan.,School of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Vo Linh Tu
- Online Research Club, Nagasaki, Japan.,University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Ranjit Tiwari
- Online Research Club, Nagasaki, Japan.,Faculty of Medicine, Institute of Medicine, Tribhuvan University, Kathmandu, 44600, Nepal
| | - Truong Van Dat
- Online Research Club, Nagasaki, Japan.,University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | | | - Kenji Hirayama
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Leading Graduate School Program, and Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan
| | - Nguyen Tien Huy
- School of Tropical Medicine and Global Health, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan. .,Institute of Research and Development, Duy Tan University, Da Nang, 550000, Vietnam.
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7
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Skwarczynski M, Chandrudu S, Rigau-Planella B, Islam MT, Cheong YS, Liu G, Wang X, Toth I, Hussein WM. Progress in the Development of Subunit Vaccines against Malaria. Vaccines (Basel) 2020; 8:vaccines8030373. [PMID: 32664421 PMCID: PMC7563759 DOI: 10.3390/vaccines8030373] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/02/2022] Open
Abstract
Malaria is a life-threatening disease and one of the main causes of morbidity and mortality in the human population. The disease also results in a major socio-economic burden. The rapid spread of malaria epidemics in developing countries is exacerbated by the rise in drug-resistant parasites and insecticide-resistant mosquitoes. At present, malaria research is focused mainly on the development of drugs with increased therapeutic effects against Plasmodium parasites. However, a vaccine against the disease is preferable over treatment to achieve long-term control. Trials to develop a safe and effective immunization protocol for the control of malaria have been occurring for decades, and continue on today; still, no effective vaccines are available on the market. Recently, peptide-based vaccines have become an attractive alternative approach. These vaccines utilize short protein fragments to induce immune responses against malaria parasites. Peptide-based vaccines are safer than traditional vaccines, relatively inexpensive to produce, and can be composed of multiple T- and B-cell epitopes integrated into one antigenic formulation. Various combinations, based on antigen choice, peptide epitope modification and delivery mechanism, have resulted in numerous potential malaria vaccines candidates; these are presently being studied in both preclinical and clinical trials. This review describes the current landscape of peptide-based vaccines, and addresses obstacles and opportunities in the production of malaria vaccines.
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Affiliation(s)
- Mariusz Skwarczynski
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Saranya Chandrudu
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Berta Rigau-Planella
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Md. Tanjir Islam
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Yee S. Cheong
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Genan Liu
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
| | - Xiumin Wang
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
- Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
- School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Woolloongabba, QLD 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
- Correspondence: (I.T.); (W.M.H.)
| | - Waleed M. Hussein
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia; (M.S.); (S.C.); (B.R.-P.); (M.T.I.); (Y.S.C.); (G.L.); (X.W.)
- Correspondence: (I.T.); (W.M.H.)
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8
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Abstract
In this review, we explore the state-of-the-art of sand fly relationships with microbiota, viruses and Leishmania, with particular emphasis on the vector immune responses. Insect-borne diseases are a major public health problem in the world. Phlebotomine sand flies are proven vectors of several aetiological agents including viruses, bacteria and the trypanosomatid Leishmania, which are responsible for diseases such as viral encephalitis, bartonellosis and leishmaniasis, respectively. All metazoans in nature coexist intimately with a community of commensal microorganisms known as microbiota. The microbiota has a fundamental role in the induction, maturation and function of the host immune system, which can modulate host protection from pathogens and infectious diseases. We briefly review viruses of public health importance present in sand flies and revisit studies done on bacterial and fungal gut contents of these vectors. We bring this information into the context of sand fly development and immune responses. We highlight the immunity mechanisms that the insect utilizes to survive the potential threats involved in these interactions and discuss the recently discovered complex interactions among microbiota, sand fly, Leishmania and virus. Additionally, some of the alternative control strategies that could benefit from the current knowledge are considered.
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9
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Kublin JG, Mikolajczak SA, Sack BK, Fishbaugher ME, Seilie A, Shelton L, VonGoedert T, Firat M, Magee S, Fritzen E, Betz W, Kain HS, Dankwa DA, Steel RWJ, Vaughan AM, Noah Sather D, Murphy SC, Kappe SHI. Complete attenuation of genetically engineered Plasmodium falciparum sporozoites in human subjects. Sci Transl Med 2018; 9:9/371/eaad9099. [PMID: 28053159 DOI: 10.1126/scitranslmed.aad9099] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 11/21/2016] [Indexed: 12/27/2022]
Abstract
Immunization of humans with whole sporozoites confers complete, sterilizing immunity against malaria infection. However, achieving consistent safety while maintaining immunogenicity of whole parasite vaccines remains a formidable challenge. We generated a genetically attenuated Plasmodium falciparum (Pf) malaria parasite by deleting three genes expressed in the pre-erythrocytic stage (Pf p52-/p36-/sap1-). We then tested the safety and immunogenicity of the genetically engineered (Pf GAP3KO) sporozoites in human volunteers. Pf GAP3KO sporozoites were delivered to 10 volunteers using infected mosquito bites with a single exposure consisting of 150 to 200 bites per subject. All subjects remained blood stage-negative and developed inhibitory antibodies to sporozoites. GAP3KO rodent malaria parasites engendered complete, protracted immunity against infectious sporozoite challenge in mice. The results warrant further clinical testing of Pf GAP3KO and its potential development into a vaccine strain.
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Affiliation(s)
- James G Kublin
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA. .,Department of Global Health, University of Washington, Seattle, WA 98195, USA.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Sebastian A Mikolajczak
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Brandon K Sack
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Matt E Fishbaugher
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Annette Seilie
- Department of Laboratory Medicine, University of Washington, 1959 Northeast Pacific Street, NW150, Seattle, WA 98195-7110, USA
| | - Lisa Shelton
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Tracie VonGoedert
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Melike Firat
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Sara Magee
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Emma Fritzen
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Will Betz
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Heather S Kain
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Dorender A Dankwa
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Ryan W J Steel
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Ashley M Vaughan
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - D Noah Sather
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Sean C Murphy
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA.,Department of Laboratory Medicine, University of Washington, 1959 Northeast Pacific Street, NW150, Seattle, WA 98195-7110, USA.,Center for Emerging and Re-emerging Infectious Diseases and Department of Microbiology, University of Washington, 750 Republican Street, E630, Seattle, WA 98109, USA
| | - Stefan H I Kappe
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA. .,Department of Global Health, University of Washington, Seattle, WA 98195, USA
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10
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Expression of truncated Babesia microti apical membrane protein 1 and rhoptry neck protein 2 and evaluation of their protective efficacy. Exp Parasitol 2016; 172:5-11. [PMID: 27876473 DOI: 10.1016/j.exppara.2016.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/04/2016] [Accepted: 11/18/2016] [Indexed: 11/20/2022]
Abstract
In this study, we evaluated the protective effect of recombinant Babesia microti apical membrane protein 1 (rBmAMA1) and rhoptry neck protein 2 (rBmRON2) against B. microti infection using a hamster model. The genes encoding the predicted domains I and II of BmAMA1 and the gene encoding the predicted transmembrane regions 2 and 3 of BmRON2 were expressed as His fusion recombinant proteins in Escherichia coli. Three groups with 5 hamsters in each group were immunized with rBmAMA1, rBmRON2 and rBmAMA1+rBmRON2, then challenged with B. microti. The result showed that only the group immunized with rBmAMA1+rBmRON2 exhibited limited protection against B. microti challenge infection, characterized by significant decreased of parasitemia and higher hematocrit values from day 6-10 post challenge infection. However, there was no significant difference in the groups immunized with rBmAMA1 or rBmRON2 alone. The absence of a significant difference in the total amount of antibodies against rBmAMA1 and rBmRON2 between the group immunized with single and combined proteins. This result suggests that the protection cannot be solely attributed to the quantity of antibodies produced, but also to their ability to target important epitopes from both antigens. These results suggest that combined immunization with rBmAMA1 and rBmRON2 is a promising strategy against B. microti.
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Dalai SK, Yadav N, Patidar M, Patel H, Singh AP. Liver-Stage Specific Response among Endemic Populations: Diet and Immunity. Front Immunol 2015; 6:125. [PMID: 25852693 PMCID: PMC4367437 DOI: 10.3389/fimmu.2015.00125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/06/2015] [Indexed: 11/22/2022] Open
Abstract
Developing effective anti-malarial vaccine has been a challenge for long. Various factors including complex life cycle of parasite and lack of knowledge of stage specific critical antigens are some of the reasons. Moreover, inadequate understanding of the immune responses vis-à-vis sterile protection induced naturally by Plasmodia infection has further compounded the problem. It has been shown that people living in endemic areas take years to develop protective immunity to blood stage infection. But hardly anyone believes that immunity to liver-stage infection could be developed. Various experimental model studies using attenuated parasite suggest that liver-stage immunity might exist among endemic populations. This could be induced because of the attenuation of parasite in liver by various compounds present in the diet of endemic populations.
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Affiliation(s)
| | - Naveen Yadav
- Institute of Science, Nirma University , Ahmedabad , India
| | - Manoj Patidar
- Institute of Science, Nirma University , Ahmedabad , India
| | - Hardik Patel
- Institute of Science, Nirma University , Ahmedabad , India
| | - Agam Prasad Singh
- Infectious Diseases Laboratory, National Institute of Immunology , New Delhi , India
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Peng X, Keitany GJ, Vignali M, Chen L, Gibson C, Choi K, Huang F, Wang R. Artesunate versus chloroquine infection-treatment-vaccination defines stage-specific immune responses associated with prolonged sterile protection against both pre-erythrocytic and erythrocytic Plasmodium yoelii infection. THE JOURNAL OF IMMUNOLOGY 2014; 193:1268-77. [PMID: 24958899 DOI: 10.4049/jimmunol.1400296] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sterile protection against malaria infection can be achieved through vaccination of mice and humans with whole Plasmodium spp. parasites. One such method, known as infection-treatment-vaccination (ITV), involves immunization with wild type sporozoites (spz) under drug coverage. In this work, we used the different effects of antimalarial drugs chloroquine (CQ) and artesunate (AS) on blood stage (BS) parasites to dissect the stage-specific immune responses in mice immunized with Plasmodium yoelii spz under either drug, as well as their ability to protect mice against challenge with spz or infected RBCs (iRBCs). Whereas CQ-ITV induced sterile protection against challenge with both spz and iRBCs, AS-ITV only induced sterile protection against spz challenge. Importantly, AS-ITV delayed the onset of BS infection, indicating that both regimens induced cross-stage immunity. Moreover, both CQ- and AS-ITV induced CD8(+) T cells in the liver that eliminated malaria-infected hepatocytes in vitro, as well as Abs that recognized pre-erythrocytic parasites. Sera from both groups of mice inhibited spz invasion of hepatocytes in vitro, but only CQ-ITV induced high levels of anti-BS Abs. Finally, passive transfer of sera from CQ-ITV-treated mice delayed the onset of erythrocytic infection in the majority of mice challenged with P. yoelii iRBCs. Besides constituting the first characterization, to our knowledge, of AS-ITV as a vaccination strategy, our data show that ITV strategies that lead to subtle differences in the persistence of parasites in the blood enable the characterization of the resulting immune responses, which will contribute to future research in vaccine design and malaria interventions.
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Affiliation(s)
- Xiaohong Peng
- Department of Pathogenic Biology, Third Military Medical University, Chongqing 400038, China; Seattle Biomedical Research Institute, Seattle, WA 98109; and
| | | | - Marissa Vignali
- Seattle Biomedical Research Institute, Seattle, WA 98109; and
| | - Lin Chen
- Department of Pathogenic Biology, Third Military Medical University, Chongqing 400038, China; Seattle Biomedical Research Institute, Seattle, WA 98109; and
| | - Claire Gibson
- Seattle Biomedical Research Institute, Seattle, WA 98109; and
| | - Kimberly Choi
- Seattle Biomedical Research Institute, Seattle, WA 98109; and
| | - Fusheng Huang
- Department of Pathogenic Biology, Third Military Medical University, Chongqing 400038, China
| | - Ruobing Wang
- Seattle Biomedical Research Institute, Seattle, WA 98109; and Department of Global Health, University of Washington, Seattle, WA 98125
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Abstract
Mosquito-borne diseases are causing a substantial burden of mortality, morbidity and economic loss in many parts of the world, despite current control efforts, and new complementary approaches to controlling these diseases are needed. One promising class of new interventions under development involves the heritable modification of the mosquito by insertion of novel genes into the nucleus or of Wolbachia endosymbionts into the cytoplasm. Once released into a target population, these modifications can act to reduce one or more components of the mosquito population's vectorial capacity (e.g. the number of female mosquitoes, their longevity or their ability to support development and transmission of the pathogen). Some of the modifications under development are designed to be self-limiting, in that they will tend to disappear over time in the absence of recurrent releases (and hence are similar to the sterile insect technique, SIT), whereas other modifications are designed to be self-sustaining, spreading through populations even after releases stop (and hence are similar to traditional biological control). Several successful field trials have now been performed with Aedes mosquitoes, and such trials are helping to define the appropriate developmental pathway for this new class of intervention.
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Affiliation(s)
- Austin Burt
- Department of Life Sciences, Imperial College London, , Silwood Park, Ascot, Berks SL5 7PY, UK
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14
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Model for in vivo assessment of humoral protection against malaria sporozoite challenge by passive transfer of monoclonal antibodies and immune serum. Infect Immun 2013; 82:808-17. [PMID: 24478094 DOI: 10.1128/iai.01249-13] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Evidence from clinical trials of malaria vaccine candidates suggests that both cell-mediated and humoral immunity to pre-erythrocytic parasite stages can provide protection against infection. Novel pre-erythrocytic antibody (Ab) targets could be key to improving vaccine formulations, which are currently based on targeting antigens such as the circumsporozoite protein (CSP). However, methods to assess the effects of sporozoite-specific Abs on pre-erythrocytic infection in vivo remain underdeveloped. Here, we combined passive transfer of monoclonal Abs (MAbs) or immune serum with a luciferase-expressing Plasmodium yoelii sporozoite challenge to assess Ab-mediated inhibition of liver infection in mice. Passive transfer of a P. yoelii CSP MAb showed inhibition of liver infection when mice were challenged with sporozoites either intravenously or by infectious mosquito bite. However, inhibition was most potent for the mosquito bite challenge, leading to a more significant reduction of liver-stage burden and even a lack of progression to blood-stage parasitemia. This suggests that Abs provide effective protection against a natural infection. Inhibition of liver infection was also achieved by passive transfer of immune serum from whole-parasite-immunized mice. Furthermore, we demonstrated that passive transfer of a MAb against P. falciparum CSP inhibited liver-stage infection in a humanized mouse/P. falciparum challenge model. Together, these models constitute unique and sensitive in vivo methods to assess serum-transferable protection against Plasmodium sporozoite challenge.
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First-in-human evaluation of genetically attenuated Plasmodium falciparum sporozoites administered by bite of Anopheles mosquitoes to adult volunteers. Vaccine 2013; 31:4975-83. [PMID: 24029408 DOI: 10.1016/j.vaccine.2013.08.007] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/30/2013] [Accepted: 08/02/2013] [Indexed: 12/31/2022]
Abstract
BACKGROUND Immunization with genetically engineered, attenuated malaria parasites (GAP) that arrest during liver infection confers sterile protection in mouse malaria models. A first generation Plasmodium falciparum GAP (Pf p52(-)/p36(-) GAP) was previously generated by deletion of two pre-erythrocytic stage-expressed genes (P52 and P36) in the NF54 strain. METHODS A first-in-human, proof-of-concept, safety and immunogenicity clinical trial in six human volunteers was conducted. Exposure consisted of delivery of Pf p52(-)/p36(-) GAP sporozoites via infected Anopheles mosquito bite with a five-bite/volunteer exposure followed by an approximately 200-bite exposure/volunteer one month later. RESULTS The exposures were well tolerated with mild to moderate local and systemic reactions. All volunteers remained blood stage negative after low dose exposure. Five volunteers remained blood stage negative after high dose exposure. One volunteer developed peripheral parasitemia twelve days after high dose exposure. Together the findings indicate that Pf p52(-)/p36(-) GAP was severely but not completely attenuated. All six volunteers developed antibodies to CSP. Furthermore, IFN-γ responses to whole sporozoites and multiple antigens were elicited in 5 of 6 volunteers, with both CD4 and CD8 cell cytokine production detected. CONCLUSION Severe attenuation and favorable immune responses following administration of a first generation Pf p52(-)/p36(-) GAP suggests that further development of live-attenuated strains using genetic engineering should be pursued.
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Sampath S, Carrico C, Janes J, Gurumoorthy S, Gibson C, Melcher M, Chitnis CE, Wang R, Schief WR, Smith JD. Glycan masking of Plasmodium vivax Duffy Binding Protein for probing protein binding function and vaccine development. PLoS Pathog 2013; 9:e1003420. [PMID: 23853575 PMCID: PMC3681752 DOI: 10.1371/journal.ppat.1003420] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/30/2013] [Indexed: 11/19/2022] Open
Abstract
Glycan masking is an emerging vaccine design strategy to focus antibody responses to specific epitopes, but it has mostly been evaluated on the already heavily glycosylated HIV gp120 envelope glycoprotein. Here this approach was used to investigate the binding interaction of Plasmodium vivax Duffy Binding Protein (PvDBP) and the Duffy Antigen Receptor for Chemokines (DARC) and to evaluate if glycan-masked PvDBPII immunogens would focus the antibody response on key interaction surfaces. Four variants of PVDBPII were generated and probed for function and immunogenicity. Whereas two PvDBPII glycosylation variants with increased glycan surface coverage distant from predicted interaction sites had equivalent binding activity to wild-type protein, one of them elicited slightly better DARC-binding-inhibitory activity than wild-type immunogen. Conversely, the addition of an N-glycosylation site adjacent to a predicted PvDBP interaction site both abolished its interaction with DARC and resulted in weaker inhibitory antibody responses. PvDBP is composed of three subdomains and is thought to function as a dimer; a meta-analysis of published PvDBP mutants and the new DBPII glycosylation variants indicates that critical DARC binding residues are concentrated at the dimer interface and along a relatively flat surface spanning portions of two subdomains. Our findings suggest that DARC-binding-inhibitory antibody epitope(s) lie close to the predicted DARC interaction site, and that addition of N-glycan sites distant from this site may augment inhibitory antibodies. Thus, glycan resurfacing is an attractive and feasible tool to investigate protein structure-function, and glycan-masked PvDBPII immunogens might contribute to P. vivax vaccine development. An important goal of many vaccine efforts is to inhibit pathogen invasion of host cells, but few approaches exist to target vaccine antibodies on invasion blocking epitopes. Glycan masking is a vaccine design strategy to hide protein surfaces with carbohydrates and focus antibodies on exposed surfaces. This approach has mostly been evaluated on the heavily glycosylated HIV envelope glycoprotein, but it has never been tested on eukaryotic pathogens, such as Plasmodium, which have limited N-glycosylation machinery and therefore may provide a better platform to explore this strategy. Here, we used glycan masking to investigate the binding interaction between Plasmodium vivax Duffy binding protein (PvDBP) and the Duffy Antigen Receptor for Chemokines (DARC). This study showed that addition of an N-glycan site in a predicted host interaction surface abolished binding and potentially covered up an inhibitory antibody epitope. In contrast, addition of multiple N-glycan sites distant from predicted interaction surfaces did not inhibit binding but did slightly enhance elicitation of inhibitory antibodies. This analysis shows that glycan resurfacing offers an integrated approach to characterize protein function and immunogenicity and that glycan resurfacing of PvDBPII immunogens may have utility in P. vivax-malaria vaccine development.
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Affiliation(s)
- Sowmya Sampath
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Chris Carrico
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Joel Janes
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Sairam Gurumoorthy
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Claire Gibson
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Martin Melcher
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Chetan E. Chitnis
- International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Ruobing Wang
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - William R. Schief
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Department of Immunology and Microbial Science and IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, California, United States of America
- Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (WRS); (JDS)
| | - Joseph D. Smith
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
- Department of Pathobiology, University of Washington, Seattle, Washington, United States of America
- * E-mail: (WRS); (JDS)
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17
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Vaughan AM, Mikolajczak SA, Wilson EM, Grompe M, Kaushansky A, Camargo N, Bial J, Ploss A, Kappe SHI. Complete Plasmodium falciparum liver-stage development in liver-chimeric mice. J Clin Invest 2012; 122:3618-28. [PMID: 22996664 DOI: 10.1172/jci62684] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 07/12/2012] [Indexed: 11/17/2022] Open
Abstract
Plasmodium falciparum, which causes the most lethal form of human malaria, replicates in the host liver during the initial stage of infection. However, in vivo malaria liver-stage (LS) studies in humans are virtually impossible, and in vitro models of LS development do not reconstitute relevant parasite growth conditions. To overcome these obstacles, we have adopted a robust mouse model for the study of P. falciparum LS in vivo: the immunocompromised and fumarylacetoacetate hydrolase-deficient mouse (Fah-/-, Rag2-/-, Il2rg-/-, termed the FRG mouse) engrafted with human hepatocytes (FRG huHep). FRG huHep mice supported vigorous, quantifiable P. falciparum LS development that culminated in complete maturation of LS at approximately 7 days after infection, providing a relevant model for LS development in humans. The infections allowed observations of previously unknown expression of proteins in LS, including P. falciparum translocon of exported proteins 150 (PTEX150) and exported protein-2 (EXP-2), components of a known parasite protein export machinery. LS schizonts exhibited exoerythrocytic merozoite formation and merosome release. Furthermore, FRG mice backcrossed to the NOD background and repopulated with huHeps and human red blood cells supported reproducible transition from LS infection to blood-stage infection. Thus, these mice constitute reliable models to study human LS directly in vivo and demonstrate utility for studies of LS-to-blood-stage transition of a human malaria parasite.
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Affiliation(s)
- Ashley M Vaughan
- Seattle Biomedical Research Institute, Seattle, Washington 98109, USA
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Goyal M, Singh P, Alam A, Das SK, Iqbal MS, Dey S, Bindu S, Pal C, Das SK, Panda G, Bandyopadhyay U. Aryl aryl methyl thio arenes prevent multidrug-resistant malaria in mouse by promoting oxidative stress in parasites. Free Radic Biol Med 2012; 53:129-42. [PMID: 22588006 DOI: 10.1016/j.freeradbiomed.2012.04.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 04/18/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
Abstract
We have synthesized a new series of aryl aryl methyl thio arenes (AAMTAs) and evaluated antimalarial activity in vitro and in vivo against drug-resistant malaria. These compounds interact with free heme, inhibit hemozoin formation, and prevent Plasmodium falciparum growth in vitro in a concentration-dependent manner. These compounds concentration dependently promote oxidative stress in Plasmodium falciparum as evident from the generation of intraparasitic oxidants, protein carbonyls, and lipid peroxidation products. Furthermore, AAMTAs deplete intraparasite GSH levels, which is essential for antioxidant defense and survival during intraerythrocytic stages. These compounds displayed potent antimalarial activity not only in vitro but also in vivo against multidrug-resistant Plasmodium yoelii dose dependently in a mouse model. The mixtures of enantiomers of AAMTAs containing 3-pyridyl rings were found to be more efficient in providing antimalarial activity. Efforts have been made to synthesize achiral AAMTAs 17-23 and among them, compound 18 showed significant antimalarial activity in vivo.
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Affiliation(s)
- Manish Goyal
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
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Kappe SHI, Vaughan AM, Boddey JA, Cowman AF. That Was Then But This Is Now: Malaria Research in the Time of an Eradication Agenda. Science 2010; 328:862-6. [PMID: 20466924 DOI: 10.1126/science.1184785] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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