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Dick JK, Hart GT. Natural Killer Cell Antibody-Dependent Cellular Cytotoxicity (ADCC) Activity Against Plasmodium falciparum-Infected Red Blood Cells. Methods Mol Biol 2022; 2470:641-657. [PMID: 35881380 DOI: 10.1007/978-1-0716-2189-9_48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Antibody-dependent cellular cytotoxicity (ADCC) is a mechanism of cell defense that bridges the innate and adaptive immune systems. ADCC has been found to be a major route of immune protection against both viral infections and cancer. Recently, natural killer (NK) cell-mediated ADCC has been shown as a mechanism of parasite clearance and protection against malaria (Hart et al. J Exp Med 216(6):1280-1290, 2019). NK cells bind to antibodies on the surface of Plasmodium falciparum infected red blood cells (iRBCs) via their Fc receptor, FcγRIIIa (CD16). This interaction induces the release of lytic granules (degranulation) by NK cells, which contain perforin, granzyme B, and granulysin, as well as the secretion of IFNγ. ADCC subsequently limits the growth of Plasmodium falciparum in vitro (Arora et al. Elife:7, e36806, 2018). Because NK cell-mediated ADCC has been shown to be important in malaria parasite clearance and protection, further studies understanding ADCC in malaria are warranted (Hart et al. J Exp Med 216(6):1280-1290, 2019). Therefore, this protocol describes methods to perform an in vitro ADCC functional assay with iRBCs. Specifically, it includes protocols on how to grow and culture iRBCs, how to culture peripheral blood mononuclear cells (PMBCs), and how to do in vitro PBMC assays to measure NK degranulation and IFNγ production as measures of NK ADCC function.
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Affiliation(s)
- Jenna Kelly Dick
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA
- Department of Medicine, Division of Infectious Disease and International Medicine, University of Minnesota, Microbiology Research Facility, Minneapolis, MN, USA
- Medical Scientist Training Program, University of Minnesota, Minneapolis, MN, USA
| | - Geoffrey Thomas Hart
- Center for Immunology, University of Minnesota, Minneapolis, MN, USA.
- Department of Medicine, Division of Infectious Disease and International Medicine, University of Minnesota, Microbiology Research Facility, Minneapolis, MN, USA.
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3
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Pereira DMS, Carvalho Júnior AR, Lacerda EMDCB, da Silva LCN, Marinho CRF, André E, Fernandes ES. Oxidative and nitrosative stresses in cerebral malaria: can we target them to avoid a bad prognosis? J Antimicrob Chemother 2020; 75:1363-1373. [PMID: 32105324 DOI: 10.1093/jac/dkaa032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is currently a global effort to reduce malaria morbidity and mortality. However, malaria still results in the deaths of thousands of people every year. Malaria is caused by Plasmodium spp., parasites transmitted through the bite of an infected female Anopheles mosquito. Treatment timing plays a decisive role in reducing mortality and sequelae associated with the severe forms of the disease such as cerebral malaria (CM). The available antimalarial therapy is considered effective but parasite resistance to these drugs has been observed in some countries. Antimalarial drugs act by increasing parasite lysis, especially through targeting oxidative stress pathways. Here we discuss the roles of reactive oxygen species and reactive nitrogen intermediates in CM as a result of host-parasite interactions. We also present evidence of the potential contribution of oxidative and nitrosative stress-based antimalarial drugs to disease treatment and control.
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Affiliation(s)
| | | | | | | | | | - Eunice André
- Departamento de Farmacologia, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Elizabeth Soares Fernandes
- Programa de Pós-graduação, Universidade CEUMA, São Luís, MA, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, PR, Brazil.,Faculdades Pequeno Príncipe, Curitiba, PR, Brazil
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Fitness Loss under Amino Acid Starvation in Artemisinin-Resistant Plasmodium falciparum Isolates from Cambodia. Sci Rep 2018; 8:12622. [PMID: 30135481 PMCID: PMC6105667 DOI: 10.1038/s41598-018-30593-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/31/2018] [Indexed: 11/09/2022] Open
Abstract
Artemisinin is the most rapidly effective drug for Plasmodium falciparum malaria treatment currently in clinical use. Emerging artemisinin-resistant parasites pose a great global health risk. At present, the level of artemisinin resistance is still relatively low with evidence pointing towards a trade-off between artemisinin resistance and fitness loss. Here we show that artemisinin-resistant P. falciparum isolates from Cambodia manifested fitness loss, showing fewer progenies during the intra-erythrocytic developmental cycle. The loss in fitness was exacerbated under the condition of low exogenous amino acid supply. The resistant parasites failed to undergo maturation, whereas their drug-sensitive counterparts were able to complete the erythrocytic cycle under conditions of amino acid deprivation. The artemisinin-resistant phenotype was not stable, and loss of the phenotype was associated with changes in the expression of a putative target, Exp1, a membrane glutathione transferase. Analysis of SNPs in haemoglobin processing genes revealed associations with parasite clearance times, suggesting changes in haemoglobin catabolism may contribute to artemisinin resistance. These findings on fitness and protein homeostasis could provide clues on how to contain emerging artemisinin-resistant parasites.
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Quintana MDP, Ch’ng JH, Zandian A, Imam M, Hultenby K, Theisen M, Nilsson P, Qundos U, Moll K, Chan S, Wahlgren M. SURGE complex of Plasmodium falciparum in the rhoptry-neck (SURFIN4.2-RON4-GLURP) contributes to merozoite invasion. PLoS One 2018; 13:e0201669. [PMID: 30092030 PMCID: PMC6084945 DOI: 10.1371/journal.pone.0201669] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/19/2018] [Indexed: 12/25/2022] Open
Abstract
Plasmodium falciparum invasion into red blood cells (RBCs) is a complex process engaging proteins on the merozoite surface and those contained and sequentially released from the apical organelles (micronemes and rhoptries). Fundamental to invasion is the formation of a moving junction (MJ), a region of close apposition of the merozoite and the RBC plasma membranes, through which the merozoite draws itself before settling into a newly formed parasitophorous vacuole (PV). SURFIN4.2 was identified at the surface of the parasitized RBCs (pRBCs) but was also found apically associated with the merozoite. Using antibodies against the N-terminus of the protein we show the presence of SURFIN4.2 in the neck of the rhoptries, its secretion into the PV and shedding into the culture supernatant upon schizont rupture. Using immunoprecipitation followed by mass spectrometry we describe here a novel protein complex we have named SURGE where SURFIN4.2 forms interacts with the rhoptry neck protein 4 (RON4) and the Glutamate Rich Protein (GLURP). The N-terminal cysteine-rich-domain (CRD) of SURFIN4.2 mediates binding to the RBC membrane and its interaction with RON4 suggests its involvement in the contact between the merozoite apex and the RBC at the MJ. Supporting this suggestion, we also found that polyclonal antibodies to the extracellular domain (including the CRD) of SURFIN4.2 partially inhibit merozoite invasion. We propose that the formation of the SURGE complex participates in the establishment of parasite infection within the PV and the RBCs.
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Affiliation(s)
- Maria del Pilar Quintana
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Jun-Hong Ch’ng
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Arash Zandian
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH-Royal Institutet of Technology, Stockholm, Sweden
| | - Maryam Imam
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Kjell Hultenby
- Division of Clinical Research Centre, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Peter Nilsson
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH-Royal Institutet of Technology, Stockholm, Sweden
| | - Ulrika Qundos
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH-Royal Institutet of Technology, Stockholm, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Sherwin Chan
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
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Wahlgren M, Goel S, Akhouri RR. Variant surface antigens of Plasmodium falciparum and their roles in severe malaria. Nat Rev Microbiol 2017; 15:479-491. [DOI: 10.1038/nrmicro.2017.47] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Sake CS, Ngu L, Ambada G, Chedjou JP, Nji N, Tchadji JC, Lissom A, Tchouangueu TF, Djukouo L, Njambe G, Garcia R, Gutierrez A, Bopda Waffo A, Park CG, Mbacham W, Etoa FX, Nchinda GW. The Effect of Antiretroviral Naïve HIV-1 Infection on the Ability of Natural Killer Cells to Produce IFN-γ upon Exposure to Plasmodium falciparum-Infected Erythrocytes. Biomed Hub 2017; 2:1-13. [PMID: 31988903 PMCID: PMC6945957 DOI: 10.1159/000467386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Background In sub-Saharan Africa, intense perennial Plasmodium species transmission coincides with areas of high prevalence of the human immunodeficiency virus type 1 (HIV) infection. This implies that antiretroviral naïve HIV-infected people living within these regions are repeatedly exposed to Plasmodium species infection and consequently malaria. Natural killer (NK) cells are known to contribute to malaria immunity through the production of IFN-γ after exposure to Plasmodium falciparum-infected erythrocytes (infected red blood cells [iRBC]). However, in antiretroviral naïve HIV-1 infection, these functions could be impaired. In this study we assess the ability of NK cells from antiretroviral naïve HIV-1-infected people to respond to iRBC. Method Magnetically sorted NK cells from antiretroviral naïve HIV-1-infected people were tested for their ability to respond to iRBC following in vitro coculture. NK cell IFN-γ production after coculture was measured through multiparametric flow cytometry analysis. Results Our data show a significant reduction (p = 0.03) in IFN-γ production by NK cells from antiretroviral naïve HIV-1-infected people after coculture with iRBCs. This was in contrast to the NK cell response from healthy controls, which demonstrated elevated IFN-γ production. NK cell IFN-γ production from untreated HIV-1-infected participants correlated inversely with the viral load (r = −0.5, p = 0.02) and positively with total helper CD4+ T-cell count (r = 0.4, p = 0.04). Thus, antiretroviral naïve HIV-1 infection can dampen NK cell-mediated immunity to P. falciparum infection in malaria-intense regions. This could in effect escalate morbidity and mortality in people chronically infected with HIV-1.
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Affiliation(s)
- Carole Stéphanie Sake
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Microbiology, University of Yaoundé I, Yaoundé, Cameroon.,Department of Biochemistry, University of Yaoundé I, Yaoundé, Cameroon
| | - Loveline Ngu
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Biochemistry, University of Yaoundé I, Yaoundé, Cameroon
| | - Georgia Ambada
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Animal Biology and Physiology, University of Yaoundé I, Yaoundé, Cameroon
| | - Jean Paul Chedjou
- Department of Animal Biology and Physiology, University of Yaoundé I, Yaoundé, Cameroon.,The Biotechnology Center, University of Yaounde I, Yaoundé, Cameroon
| | - Nadesh Nji
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon
| | - Jules Colince Tchadji
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Animal Biology and Physiology, University of Yaoundé I, Yaoundé, Cameroon
| | - Abel Lissom
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Animal Biology and Physiology, University of Yaoundé I, Yaoundé, Cameroon
| | - Thibau Flaurant Tchouangueu
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Biochemistry, University of Dschang, Dschang, Cameroon
| | - Larissa Djukouo
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Biochemistry, University of Yaoundé I, Yaoundé, Cameroon
| | - Ghislain Njambe
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon.,Department of Animal Biology and Physiology, University of Yaoundé I, Yaoundé, Cameroon
| | - Rosario Garcia
- CSCB (Centre de santé catholique de Bikop), Bikop, Cameroon
| | - Anna Gutierrez
- CSCB (Centre de santé catholique de Bikop), Bikop, Cameroon.,Department of Biological Sciences, Alabama State University, Montgomery, AL, USA
| | - Alain Bopda Waffo
- Department of Biological Sciences, Alabama State University, Montgomery, AL, USA
| | - Chae Gyu Park
- Laboratory of Immunology, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Wilfried Mbacham
- Department of Biochemistry, University of Yaoundé I, Yaoundé, Cameroon.,The Biotechnology Center, University of Yaounde I, Yaoundé, Cameroon.,The Department of Biochemistry and Physiology, Faculty of Medicine, University of Yaounde I, Yaoundé, Cameroon
| | - François-Xavier Etoa
- Department of Microbiology, University of Yaoundé I, Yaoundé, Cameroon.,University of Douala, Douala, Cameroon
| | - Godwin W Nchinda
- Laboratory of Vaccinology/Biobanking, CIRCB, Messa Yaounde, Cameroon
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Hou N, Zou Y, Piao X, Liu S, Wang L, Li S, Chen Q. T-Cell Immunoglobulin- and Mucin-Domain-Containing Molecule 3 Signaling Blockade Improves Cell-Mediated Immunity Against Malaria. J Infect Dis 2016; 214:1547-1556. [PMID: 27638944 DOI: 10.1093/infdis/jiw428] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/06/2016] [Indexed: 02/06/2023] Open
Abstract
Cell-mediated immune responses play important roles in immune protection against Plasmodium infection. However, impaired immunity, such as lymphocyte exhaustion, is a common phenomenon in malaria. T-cell immunoglobulin- and mucin-domain-containing molecule 3 (Tim-3) is an important regulatory molecule in cell-mediated immunity and has been implicated in malaria. In this study, it was found that Tim-3 expression on key populations of lymphocytes was significantly increased in both Plasmodium falciparum-infected patients and Plasmodium berghei ANKA (PbANKA)-infected C57BL/6 mice. Upregulation of Tim-3 led to lymphocyte exhaustion, while blocking Tim-3 signaling with an anti-Tim-3 antibody restored lymphocyte activity in Plasmodium infections. Further, anti-Tim-3 treatment accelerated the parasite clearance and relieved the symptoms of cerebral malaria in PbANKA-infected mice. In conclusion, Tim-3 on immune cells negatively regulates cell-mediated immunity against Plasmodium infection, and blocking Tim-3 signaling enhances sterile immunity and may play a protective role during malarial parasite infections.
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Affiliation(s)
- Nan Hou
- Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Yang Zou
- Beijing Tropical Medicine Research Institute, Beijing Key Laboratory for Research on Prevention and Treatment of Tropical Diseases, Beijing Friendship Hospital, Capital Medical University, Beijing
| | - Xianyu Piao
- Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Shuai Liu
- Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Lei Wang
- Beijing Tropical Medicine Research Institute, Beijing Key Laboratory for Research on Prevention and Treatment of Tropical Diseases, Beijing Friendship Hospital, Capital Medical University, Beijing
| | - Shanshan Li
- Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Qijun Chen
- Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College.,Key Laboratory of Zoonosis, Shenyang Agriculture University, Shenyang City, People's Republic of China
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Moreira CK, Naissant B, Coppi A, Bennett BL, Aime E, Franke-Fayard B, Janse CJ, Coppens I, Sinnis P, Templeton TJ. The Plasmodium PHIST and RESA-Like Protein Families of Human and Rodent Malaria Parasites. PLoS One 2016; 11:e0152510. [PMID: 27022937 PMCID: PMC4811531 DOI: 10.1371/journal.pone.0152510] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/15/2016] [Indexed: 11/19/2022] Open
Abstract
The phist gene family has members identified across the Plasmodium genus, defined by the presence of a domain of roughly 150 amino acids having conserved aromatic residues and an all alpha-helical structure. The family is highly amplified in P. falciparum, with 65 predicted genes in the genome of the 3D7 isolate. In contrast, in the rodent malaria parasite P. berghei 3 genes are identified, one of which is an apparent pseudogene. Transcripts of the P. berghei phist genes are predominant in schizonts, whereas in P. falciparum transcript profiles span different asexual blood stages and gametocytes. We pursued targeted disruption of P. berghei phist genes in order to characterize a simplistic model for the expanded phist gene repertoire in P. falciparum. Unsuccessful attempts to disrupt P. berghei PBANKA_114540 suggest that this phist gene is essential, while knockout of phist PBANKA_122900 shows an apparent normal progression and non-essential function throughout the life cycle. Epitope-tagging of P. falciparum and P. berghei phist genes confirmed protein export to the erythrocyte cytoplasm and localization with a punctate pattern. Three P. berghei PEXEL/HT-positive exported proteins exhibit at least partial co-localization, in support of a common vesicular compartment in the cytoplasm of erythrocytes infected with rodent malaria parasites.
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Affiliation(s)
- Cristina K. Moreira
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021, United States of America
| | - Bernina Naissant
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021, United States of America
| | - Alida Coppi
- Department of Medical Parasitology, NYU School of Medicine, New York, NY, 10010, United States of America
| | - Brandy L. Bennett
- Department of Medical Parasitology, NYU School of Medicine, New York, NY, 10010, United States of America
| | - Elena Aime
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Blandine Franke-Fayard
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Chris J. Janse
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, United States of America
| | - Photini Sinnis
- Department of Medical Parasitology, NYU School of Medicine, New York, NY, 10010, United States of America
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, United States of America
| | - Thomas J. Templeton
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10021, United States of America
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki 852-8523, Japan
- * E-mail:
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Architecture of Human IgM in Complex with P. falciparum Erythrocyte Membrane Protein 1. Cell Rep 2016; 14:723-736. [PMID: 26776517 DOI: 10.1016/j.celrep.2015.12.067] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 09/30/2015] [Accepted: 12/11/2015] [Indexed: 11/23/2022] Open
Abstract
Plasmodium falciparum virulence is associated with sequestration of infected erythrocytes. Microvascular binding mediated by PfEMP1 in complex with non-immune immunoglobulin M (IgM) is common among parasites that cause both severe childhood malaria and pregnancy-associated malaria. Here, we present cryo-molecular electron tomography structures of human IgM, PfEMP1 and their complex. Three-dimensional reconstructions of IgM reveal that it has a dome-like core, randomly oriented Fab2s units, and the overall shape of a turtle. PfEMP1 is a C- shaped molecule with a flexible N terminus followed by an arc-shaped backbone and a bulky C terminus that interacts with IgM. Our data demonstrate that the PfEMP1 binding pockets on IgM overlap with those of C1q, and the bulkiness of PfEMP1 limits the capacity of IgM to interact with PfEMP1. We suggest that P. falciparum exploits IgM to cluster PfEMP1 into an organized matrix to augment its affinity to host cell receptors.
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Binding of subdomains 1/2 of PfEMP1-DBL1α to heparan sulfate or heparin mediates Plasmodium falciparum rosetting. PLoS One 2015; 10:e0118898. [PMID: 25742651 PMCID: PMC4351205 DOI: 10.1371/journal.pone.0118898] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 01/20/2015] [Indexed: 11/24/2022] Open
Abstract
The capacity of Plasmodium falciparum parasitized erythrocytes (pRBC) to adhere to the endothelial lining in the microvasculature and to red blood cells (RBC) is associated with the virulence of the parasite, the pathogenesis and development of severe malaria. Rosetting, the binding of uninfected RBC to pRBC, is frequently observed in individuals with severe malaria and is mediated by the N-terminal NTS-DBL1α domain of the adhesin Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) expressed at the surface of the pRBC. Heparan sulfate has been suggested to be an important receptor for the NTS-DBL1α variant IT4var60 expressed by the parasite FCR3S1.2. Here, we have determined the binding site of NTS-DBL1α (IT4var60) to the RBC and heparin using a set of recombinant, mutated proteins expressed in and purified from E. coli. All the variants were studied for their ability to bind to RBC, their capacities to disrupt FCR3S1.2 rosettes, their affinities for heparin and their binding to rosette-disruptive mAbs. Our results suggest that NTS-DBL1α mediates binding to RBC through a limited number of basic amino acid residues localized on the surface of subdomains 1 (SD1) and 2 (SD2). The SD2-binding site is localized in close proximity to one of two previously identified binding sites in the rosetting PfEMP1 of the parasite PaloAlto-varO. The binding site in SD2 of NTS-DBL1α could represent a template for the development of anti-rosetting drugs.
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Albrecht L, Angeletti D, Moll K, Blomqvist K, Valentini D, D'Alexandri FL, Maurer M, Wahlgren M. B-cell epitopes in NTS-DBL1α of PfEMP1 recognized by human antibodies in Rosetting Plasmodium falciparum. PLoS One 2014; 9:e113248. [PMID: 25438249 PMCID: PMC4249881 DOI: 10.1371/journal.pone.0113248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/21/2014] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum is the most lethal of the human malaria parasites. The virulence is associated with the capacity of the infected red blood cell (iRBC) to sequester inside the deep microvasculature where it may cause obstruction of the blood-flow when binding is excessive. Rosetting, the adherence of the iRBC to uninfected erythrocytes, has been found associated with severe malaria and found to be mediated by the NTS-DBL1α-domain of Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1). Here we show that the reactivity of plasma of Cameroonian children with the surface of the FCR3S1.2-iRBC correlated with the capacity to disrupt rosettes and with the antibody reactivity with a recombinant PfEMP1 (NTS-DBL1α of IT4var60) expressed by parasite FCR3S1.2. The plasma-reactivity in a microarray, consisting of 96 overlapping 15-mer long peptides covering the NTS-DBL1α domain from IT4var60 sequence, was compared with their capacity to disrupt rosettes and we identified five peptides where the reactivity were correlated. Three of the peptides were localized in subdomain-1 and 2. The other two peptide-sequences were localized in the NTS-domain and in subdomain-3. Further, principal component analysis and orthogonal partial least square analysis generated a model that supported these findings. In conclusion, human antibody reactivity with short linear-peptides of NTS-DBL1α of PfEMP1 suggests subdomains 1 and 2 to hold anti-rosetting epitopes recognized by anti-rosetting antibodies. The data suggest rosetting to be mediated by the variable areas of PfEMP1 but also to involve structurally relatively conserved areas of the molecule that may induce biologically active antibodies.
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Affiliation(s)
- Letusa Albrecht
- Department of Microbiology, Tumor- and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
- * E-mail: (MW); (LA)
| | - Davide Angeletti
- Department of Microbiology, Tumor- and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor- and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Karin Blomqvist
- Department of Microbiology, Tumor- and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Davide Valentini
- Therapeutic Immunology (TIM), Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- CAST, Karolinska University Hospital, Huddinge, Sweden
| | | | - Markus Maurer
- Therapeutic Immunology (TIM), Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- CAST, Karolinska University Hospital, Huddinge, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumor- and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
- * E-mail: (MW); (LA)
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13
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Human natural killer cells control Plasmodium falciparum infection by eliminating infected red blood cells. Proc Natl Acad Sci U S A 2014; 111:1479-84. [PMID: 24474774 DOI: 10.1073/pnas.1323318111] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Immunodeficient mouse-human chimeras provide a powerful approach to study host-specific pathogens, such as Plasmodium falciparum that causes human malaria. Supplementation of immunodeficient mice with human RBCs supports infection by human Plasmodium parasites, but these mice lack the human immune system. By combining human RBC supplementation and humanized mice that are optimized for human immune cell reconstitution, we have developed RBC-supplemented, immune cell-optimized humanized (RICH) mice that support multiple cycles of P. falciparum infection. Depletion of human natural killer (NK) cells, but not macrophages, in RICH mice results in a significant increase in parasitemia. Further studies in vitro show that NK cells preferentially interact with infected RBCs (iRBCs), resulting in the activation of NK cells and the elimination of iRBCs in a contact-dependent manner. We show that the adhesion molecule lymphocyte-associated antigen 1 is required for NK cell interaction with and elimination of iRBCs. Development of RICH mice and validation of P. falciparum infection should facilitate the dissection of human immune responses to malaria parasite infection and the evaluation of therapeutics and vaccines.
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Fucosylated chondroitin sulfate inhibits Plasmodium falciparum cytoadhesion and merozoite invasion. Antimicrob Agents Chemother 2014; 58:1862-71. [PMID: 24395239 DOI: 10.1128/aac.00686-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequestration of Plasmodium falciparum-infected erythrocytes (Pf-iEs) in the microvasculature of vital organs plays a key role in the pathogenesis of life-threatening malaria complications, such as cerebral malaria and malaria in pregnancy. This phenomenon is marked by the cytoadhesion of Pf-iEs to host receptors on the surfaces of endothelial cells, on noninfected erythrocytes, and in the placental trophoblast; therefore, these sites are potential targets for antiadhesion therapies. In this context, glycosaminoglycans (GAGs), including heparin, have shown the ability to inhibit Pf-iE cytoadherence and growth. Nevertheless, the use of heparin was discontinued due to serious side effects, such as bleeding. Other GAG-based therapies were hampered due to the potential risk of contamination with prions and viruses, as some GAGs are isolated from mammals. In this context, we investigated the effects and mechanism of action of fucosylated chondroitin sulfate (FucCS), a unique and highly sulfated GAG isolated from the sea cucumber, with respect to P. falciparum cytoadhesion and development. FucCS was effective in inhibiting the cytoadherence of Pf-iEs to human lung endothelial cells and placenta cryosections under static and flow conditions. Removal of the sulfated fucose branches of the FucCS structure virtually abolished the inhibitory effects of FucCS. Importantly, FucCS rapidly disrupted rosettes at high levels, and it was also able to block parasite development by interfering with merozoite invasion. Collectively, these findings highlight the potential of FucCS as a candidate for adjunct therapy against severe malaria.
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De las Salas B, Segura C, Pabón A, Lopes SCP, Costa FTM, Blair S. Adherence to human lung microvascular endothelial cells (HMVEC-L) of Plasmodium vivax isolates from Colombia. Malar J 2013; 12:347. [PMID: 24080027 PMCID: PMC3850517 DOI: 10.1186/1475-2875-12-347] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 09/24/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND For years Plasmodium vivax has been considered the cause of benign malaria. Nevertheless, it has been observed that this parasite can produce a severe disease comparable to Plasmodium falciparum. It has been suggested that some physiopathogenic processes might be shared by these two species, such as cytoadherence. Recently, it has been demonstrated that P. vivax-infected erythrocytes (Pv-iEs) have the capacity to adhere to endothelial cells, in which intercellular adhesion molecule-1 (ICAM-1) seems to be involved in this process. METHODS Adherence capacity of 21 Colombian isolates, from patients with P. vivax mono-infection to a microvascular line of human lung endothelium (HMVEC-L) was assessed in static conditions and binding was evaluated at basal levels or in tumor necrosis factor (TNF) stimulated cells. The adherence specificity for the ICAM-1 receptor was determined through inhibition with an anti-CD54 monoclonal antibody. RESULTS The majority of P. vivax isolates, 13 out of 21 (61.9%), adhered to the HMVEC-L cells, but P. vivax adherence was at least seven times lower when compared to the four P. falciparum isolates. Moreover, HMVEC-L stimulation with TNF led to an increase of 1.6-fold in P. vivax cytoadhesion, similar to P. falciparum isolates (1.8-fold) at comparable conditions. Also, blockage of ICAM-1 receptor with specific antibodies showed a significant 50% adherence reduction. CONCLUSIONS Plasmodium vivax isolates found in Colombia are also capable of adhering specifically in vitro to lung endothelial cells, via ICAM-1 cell receptor, both at basal state and after cell stimulation with TNF. Collectively, these findings reinforce the concept of cytoadherence for P. vivax, but here, to a different endothelial cell line and using geographical distinct isolates, thus contributing to understanding P. vivax biology.
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Affiliation(s)
- Briegel De las Salas
- Grupo Malaria, Facultad de Medicina, Universidad de Antioquia UdeA, Calle 70 No, 52-21, Medellín, Colombia.
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Ribacke U, Moll K, Albrecht L, Ahmed Ismail H, Normark J, Flaberg E, Szekely L, Hultenby K, Persson KEM, Egwang TG, Wahlgren M. Improved in vitro culture of Plasmodium falciparum permits establishment of clinical isolates with preserved multiplication, invasion and rosetting phenotypes. PLoS One 2013; 8:e69781. [PMID: 23894537 PMCID: PMC3718792 DOI: 10.1371/journal.pone.0069781] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 06/12/2013] [Indexed: 11/26/2022] Open
Abstract
To be able to robustly propagate P. falciparum at optimal conditions in vitro is of fundamental importance for genotypic and phenotypic studies of both established and fresh clinical isolates. Cryo-preserved P. falciparum isolates from Ugandan children with severe or uncomplicated malaria were investigated for parasite phenotypes under different in vitro growth conditions or studied directly from the peripheral blood. The parasite cultures showed a minimal loss of parasite-mass and preserved percentage of multiple infected pRBCs to that in peripheral blood, maintained adhesive phenotypes and good outgrowth and multiplication rates when grown in suspension and supplemented with gas. In contrast, abnormal and greatly fluctuating levels of multiple infections were observed during static growth conditions and outgrowth and multiplication rates were inferior. Serum, as compared to Albumax, was found necessary for optimal presentation of PfEMP1 at the pRBC surface and/or for binding of serum proteins (immunoglobulins). Optimal in vitro growth conditions of P. falciparum therefore include orbital shaking (50 rev/min), human serum (10%) and a fixed gas composition (5% O2, 5% CO2, 90% N2). We subsequently established 100% of 76 frozen patient isolates and found rosetting with schizont pRBCs in every isolate (>26% schizont rosetting rate). Rosetting during schizogony was often followed by invasion of the bound RBC as seen by regular and time-lapse microscopy as well as transmission electron microscopy. The peripheral parasitemia, the level of rosetting and the rate of multiplication correlated positively to one another for individual isolates. Rosetting was also more frequent with trophozoite and schizont pRBCs of children with severe versus uncomplicated malaria (p<0.002; p<0.004). The associations suggest that rosetting enhances the ability of the parasite to multiply within the human host.
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Affiliation(s)
- Ulf Ribacke
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Letusa Albrecht
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Hodan Ahmed Ismail
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Johan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Emilie Flaberg
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Laszlo Szekely
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Kjell Hultenby
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Kristina E. M. Persson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | | | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Dassé R, Lefranc D, Dubucquoi S, Dussart P, Dutoit-Lefèvre V, Sendid B, Sombo Mambo F, Vermersch P, Prin L. [Singular, systemic, self-reactive IgG patterns related to age: relationship with cerebral malaria susceptibility in exposed subjects residing in an endemic area in Abidjan, Côte-d'Ivoire]. BULLETIN DE LA SOCIETE DE PATHOLOGIE EXOTIQUE (1990) 2012; 105:276-283. [PMID: 22886432 DOI: 10.1007/s13149-012-0252-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 06/19/2012] [Indexed: 06/01/2023]
Abstract
The impact of autoimmunity on malaria-infection evolution reported by various works has led us to compare reactive patterns of self-dependent systemic IgG from 54 patients aged less than 15 years old to those from 46 subjects older than 15 years. These subjects were divided into 34 Plasmodium falciparum asymptomatic carriers (ACs), 30 cases of uncomplicated malaria (UM), and 36 patients suffering from cerebral malaria (CM) living in the same endemic area. The reactivity of the plasma antibodies against human brain tissue extract was assessed by western blotting. Comparative analysis of reactive bands (linear discriminant analysis, LDA) revealed the existence of patterns that distinguish, among the more susceptible subjects aged less than 15 years old, the different clinical forms. In contrast, in less susceptible subjects aged more than 15 years old, the patterns are homogenous and do not allow the separation of these clinical forms. This self-reactive repertoire might be witnessed as an imprint of the clinical tolerance acquired during the years of living in endemic areas. The singularity of this profile under the age of 15 years might have a prognostic value.
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Affiliation(s)
- R Dassé
- Laboratoire d'immunologie EA 2686, université Lille-II, Lille cedex, France.
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Dassé R, Lefranc D, Dubucquoi S, Dussart P, Dutoit-Lefevre V, Sendid B, Sombo Mambo F, Vermersch P, Prin L. Changes Related to Age in Natural and Acquired Systemic Self-IgG Responses in Malaria. Interdiscip Perspect Infect Dis 2011; 2011:462767. [PMID: 22253622 PMCID: PMC3255176 DOI: 10.1155/2011/462767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 09/23/2011] [Indexed: 01/22/2023] Open
Abstract
Background. Absence of acquired protective immunity in endemic areas children leads to higher susceptibility to severe malaria. To investigate the involvement of regulatory process related to self-reactivity, we evaluated potent changes in auto-antibody reactivity profiles in children and older subjects living in malaria-endemic zones comparatively to none-exposed healthy controls. Methods. Analysis of IgG self-reactive footprints was performed using Western blotting against healthy brain antigens. Plasmas of 102 malaria exposed individuals (MEIs) from endemic zone, with or without cerebral malaria (CM) were compared to plasmas from non-endemic controls (NECs). Using linear discriminant and principal component analysis, immune footprints were compared by counting the number, the presence or absence of reactive bands. We identified the most discriminant bands with respect to age and clinical status. Results. A higher number of bands were recognized by IgG auto-antibodies in MEI than in NEC. Characteristic changes in systemic self-IgG-reactive repertoire were found with antigenic bands that discriminate Plasmodium falciparum infections with or without CM according to age. 8 antigenic bands distributed in MEI compared with NEC were identified while 6 other antigenic bands were distributed within MEI according to the age and clinical status. Such distortion might be due to evolutionary processes leading to pathogenic/protective events.
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Affiliation(s)
- Romuald Dassé
- Laboratoire d'Immunologie EA 2686, IMPRT-IFR 114, Faculté de Médecine Pôle Recherche, Université Lille 2, 1 Place de Verdun, 59045 Lille Cedex, France
- Laboratoire d'Immunologie et Hématologie du CHU-Cocody, Abidjan, Cote D'Ivoire
| | - Didier Lefranc
- Laboratoire d'Immunologie EA 2686, IMPRT-IFR 114, Faculté de Médecine Pôle Recherche, Université Lille 2, 1 Place de Verdun, 59045 Lille Cedex, France
| | - Sylvain Dubucquoi
- Laboratoire d'Immunologie EA 2686, IMPRT-IFR 114, Faculté de Médecine Pôle Recherche, Université Lille 2, 1 Place de Verdun, 59045 Lille Cedex, France
| | - Patricia Dussart
- Laboratoire d'Immunologie EA 2686, IMPRT-IFR 114, Faculté de Médecine Pôle Recherche, Université Lille 2, 1 Place de Verdun, 59045 Lille Cedex, France
| | - Virginie Dutoit-Lefevre
- Laboratoire d'Immunologie EA 2686, IMPRT-IFR 114, Faculté de Médecine Pôle Recherche, Université Lille 2, 1 Place de Verdun, 59045 Lille Cedex, France
| | - Boualem Sendid
- Laboratoire de Parasitologie et de Mycologie, Institute de Biologie et Pathologie, CHRU de Lille 59037 Lille, France
| | | | - Patrick Vermersch
- Service de Neurologie D, Hôpital Roger Salengro, 59037 Lille Cedex, France
| | - Lionel Prin
- Laboratoire d'Immunologie EA 2686, IMPRT-IFR 114, Faculté de Médecine Pôle Recherche, Université Lille 2, 1 Place de Verdun, 59045 Lille Cedex, France
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Kuadzi JT, Ankra-Badu G, Addae MM. Plasmodium falciparum malaria in children at a tertiary teaching hospital: ABO blood group is a risk factor. Pan Afr Med J 2011; 10:2. [PMID: 22187584 PMCID: PMC3282927 DOI: 10.4314/pamj.v10i0.72205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 09/02/2011] [Indexed: 11/18/2022] Open
Abstract
Background ABO blood group antigens are formed by terminal glycosylation of glycoproteins and glycolipid chains present on cell surfaces. Glycosylation modulates all kinds of cell-to-cell interactions and this may be relevant in malaria pathophysiology, in which adhesion has been increasingly implicated in disease severity. This study was done to determine the association between ABO phenotypes and the severity of P. falciparum malaria in children. Methods One hundred and twenty one children were assessed at the Department of Child Health, KBTH from May to August 2008. ABO blood groups were determined by agglutination. The haemoglobin measurement was done with the haematology analyzer, Sysmex KX-21N. Malaria parasites were enumerated and the presence of malaria pigment noted. Identification of P. falciparum was done. Statistical tests used were odds ratio and chi square at a significance level of p<0.05. Results 24.3% of the 121 children had severe falciparum malaria, and their mean haemoglobin was 4.49 g/dl (SD ±1.69). No significant association was found between the ABO phenotypes and malaria infection (p>0.05). Blood group A was associated with more severe malaria as compared to the blood group O individuals (Odds ratio=0.79, p>0.05); blood group AB (Odds ratio=0.14, p>0.05) and also there was a significant difference in severity of malaria between blood group O and blood group B (Odds ratio=1.28, p>0.05). Conclusion Non-O blood group children are more prone to severe malaria caused by P. falciparum malaria than the group O, despite the lack of significant association between ABO blood groups and falciparum malaria.
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Affiliation(s)
- John Teye Kuadzi
- Department of Medical Laboratory Sciences, School of Allied Health Sciences, Korle-Bu, Accra, Ghana
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20
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var gene transcription and PfEMP1 expression in the rosetting and cytoadhesive Plasmodium falciparum clone FCR3S1.2. Malar J 2011; 10:17. [PMID: 21266056 PMCID: PMC3036667 DOI: 10.1186/1475-2875-10-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 01/25/2011] [Indexed: 11/10/2022] Open
Abstract
Background The pathogenicity of Plasmodium falciparum is in part due to the ability of the parasitized red blood cell (pRBC) to adhere to intra-vascular host cell receptors and serum-proteins. Binding of the pRBC is mediated by Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), a large multi-variant molecule encoded by a family of ≈60 var genes. Methods The study of var gene transcription in the parasite clone FCR3S1.2 was performed by semi-quantitative PCR and quantitative PCR (qPCR). The expression of the major PfEMP1 in FCR3S1.2 pRBC was analysed with polyclonal sera in rosette disruption assays and immunofluorecence. Results Transcripts from var1 (FCR3S1.2var1; IT4var21) and other var genes were detected by semi-quantitative PCR but results from qPCR showed that one var gene transcript dominated over the others (FCR3S1.2var2; IT4var60). Antibodies raised in rats to the recombinant NTS-DBL1α of var2 produced in E. coli completely and dose-dependently disrupted rosettes (≈95% at a dilution of 1/5). The sera reacted with the Maurer's clefts in trophozoite stages (IFA) and to the infected erythrocyte surface (FACS) indicating that FCR3S1.2var2 encodes the dominant PfEMP1 expressed in this parasite. Conclusion The major transcript in the rosetting model parasite FCR3S1.2 is FCR3S1.2var2 (IT4var60). The results suggest that this gene encodes the PfEMP1-species responsible for the rosetting phenotype of this parasite. The activity of previously raised antibodies to the NTS-DBL1α of FCR3S1.2var1 is likely due to cross-reactivity with NTS-DBL1α of the var2 encoded PfEMP1.
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Cserti-Gazdewich CM. Plasmodium falciparum malaria and carbohydrate blood group evolution. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1751-2824.2010.01380.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Faille D, Combes V, Mitchell AJ, Fontaine A, Juhan-Vague I, Alessi MC, Chimini G, Fusaï T, Grau GE. Platelet microparticles: a new player in malaria parasite cytoadherence to human brain endothelium. FASEB J 2009; 23:3449-58. [PMID: 19535685 DOI: 10.1096/fj.09-135822] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cerebral malaria (CM) is characterized by accumulation of circulating cells within brain microvessels, among which platelets play an important role. In vitro, platelets modulate the cytoadherence of Plasmodium falciparum-parasitized red blood cells (PRBCs) to brain endothelial cells. Here we show for the first time that platelet microparticles (PMPs) are able to bind to PRBCs, thereby transferring platelet antigens to the PRBC surface. This binding is largely specific to PRBCs, because PMPs show little adherence to normal red blood cells. PMP adherence is also dependent on the P. falciparum erythrocyte membrane protein 1 variant expressed by PRBCs. PMP binding to PRBCs decreases after neutralization of PRBC surface proteins by trypsin or after treatment of PMPs with a mAb to platelet-endothelial cell adhesion molecule-1 (CD31) and glycoprotein IV (CD36). Furthermore, PMP uptake is a dynamic process that can be achieved by human brain endothelial cells (HBECs), inducing changes in the endothelial phenotype. Lastly, PMPs dramatically increase PRBC cytoadherence to HBECs. In conclusion, our study identifies several mechanisms by which PMPs may participate in CM pathogenesis while interacting with both PRBCs and HBECs. PMPs thereby provide a novel target for antagonizing interactions between vascular cells that promote microvascular sludging and blood brain barrier alteration during CM.
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Affiliation(s)
- Dorothée Faille
- Department of Pathology, University of Sydney, 92-94 Parramatta Rd, Camperdown, NSW 2042, Australia
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Abstract
Dyke-Davidoff-Masson syndrome is a disorder involving hemiatrophy or hypoplasia of 1 cerebral hemisphere secondary to an insult in the developing brain. Often this will manifest with seizures, hemiparesis, mental retardation, and facial changes. Associated with this pathology are the radiologically evident changes, such as thickening of the calvarium, hyperpneumatization of the sinuses, and dilation of the ipsilateral lateral ventricle among others. The following is a case presentation of an 18-year-old female emigrating from Ghana who presented to the emergency department with complaints of seizures diagnosed as being caused by cerebral malaria at 13 years of age. We hypothesize that the cerebral malaria and related vascular occlusion are the causes of her acquired cerebral changes. Included are computed tomography images.
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Affiliation(s)
- Sabesan Karuppiah
- Bronx Lebanon Family Medicine Residency Program, 100 Hospital Plaza Apt 608, Paterson, New Jersey 07503, USA.
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Raj DK, Mu J, Jiang H, Kabat J, Singh S, Sullivan M, Fay MP, McCutchan TF, Su XZ. Disruption of a Plasmodium falciparum multidrug resistance-associated protein (PfMRP) alters its fitness and transport of antimalarial drugs and glutathione. J Biol Chem 2008; 284:7687-96. [PMID: 19117944 PMCID: PMC2658063 DOI: 10.1074/jbc.m806944200] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
ATP-binding cassette transporters play an important role in drug resistance
and nutrient transport. In the human malaria parasite Plasmodium
falciparum, a homolog of the human p-glycoprotein (PfPgh-1) was
shown to be involved in resistance to several drugs. More recently, many
transporters were associated with higher IC50 levels in responses
to chloroquine (CQ) and quinine (QN) in field isolates. Subsequent studies,
however, could not confirm the associations, although inaccuracy in drug tests
in the later studies could contribute to the lack of associations. Here we
disrupted a gene encoding a putative multidrug resistance-associated protein
(PfMRP) that was previously shown to be associated with P. falciparum
responses to CQ and QN. Parasites with disrupted PfMRP (W2/MRPΔ) could
not grow to a parasitemia higher than 5% under normal culture conditions,
possibly because of lower efficiency in removing toxic metabolites. The
W2/MRPΔ parasite also accumulated more radioactive glutathione, CQ, and
QN and became more sensitive to multiple antimalarial drugs, including CQ, QN,
artemisinin, piperaquine, and primaquine. PfMRP was localized on the parasite
surface membrane, within membrane-bound vesicles, and along the straight side
of the D-shaped stage II gametocytes. The results suggest that PfMRP plays a
role in the efflux of glutathione, CQ, and QN and contributes to parasite
responses to multiple antimalarial drugs, possibly by pumping drugs outside
the parasite.
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Affiliation(s)
- Dipak Kumar Raj
- Laboratory of Malaria and Vector Research, Research Technologies Branch, and Biostatistical Research Branch, NIAID, National Institutes of Health, Bethesda, Maryland 20892-8132, USA
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An in vivo and in vitro model of Plasmodium falciparum rosetting and autoagglutination mediated by varO, a group A var gene encoding a frequent serotype. Infect Immun 2008; 76:5565-80. [PMID: 18809668 DOI: 10.1128/iai.00901-08] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the Saimiri sciureus monkey, erythrocytes infected with the varO antigenic variant of the Plasmodium falciparum Palo Alto 89F5 clone bind uninfected red blood cells (rosetting), form autoagglutinates, and have a high multiplication rate, three phenotypic characteristics that are associated with severe malaria in human patients. We report here that varO parasites express a var gene having the characteristics of group A var genes, and we show that the varO Duffy binding-like 1alpha(1) (DBL1alpha(1)) domain is implicated in the rosetting of both S. sciureus and human erythrocytes. The soluble varO N-terminal sequence (NTS)-DBL1alpha(1) recombinant domain, produced in a baculovirus-insect cell system, induced high titers of antibodies that reacted with varO-infected red blood cells and disrupted varO rosettes. varO parasites were culture adapted in vitro using human erythrocytes. They formed rosettes and autoagglutinates, and they had the same surface serotype and expressed the same varO gene as the monkey-propagated parasites. To develop an in vitro model with highly homogeneous varO parasites, rosette purification was combined with positive selection by panning with a varO NTS-DBL1alpha(1)-specific mouse monoclonal antibody. The single-variant, clonal parasites were used to analyze seroprevalence for varO at the village level in a setting where malaria is holoendemic (Dielmo, Senegal). We found 93.6% (95% confidence interval, 89.7 to 96.4%) seroprevalence for varO surface-reacting antibodies and 86.7% (95% confidence interval, 82.8 to 91.6%) seroprevalence for the recombinant NTS-DBL1alpha(1) domain, and virtually all permanent residents had seroconverted by the age of 5 years. These data imply that the varO model is a relevant in vivo and in vitro model for rosetting and autoagglutination that can be used for rational development of vaccine candidates and therapeutic strategies aimed at preventing malaria pathology.
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Genome-wide compensatory changes accompany drug- selected mutations in the Plasmodium falciparum crt gene. PLoS One 2008; 3:e2484. [PMID: 18575593 PMCID: PMC2424241 DOI: 10.1371/journal.pone.0002484] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 05/14/2008] [Indexed: 11/25/2022] Open
Abstract
Mutations in PfCRT (Plasmodium falciparum chloroquine-resistant transporter), particularly the substitution at amino acid position 76, confer chloroquine (CQ) resistance in P. falciparum. Point mutations in the homolog of the mammalian multidrug resistance gene (pfmdr1) can also modulate the levels of CQ response. Moreover, parasites with the same pfcrt and pfmdr1 alleles exhibit a wide range of drug sensitivity, suggesting that additional genes contribute to levels of CQ resistance (CQR). Reemergence of CQ sensitive parasites after cessation of CQ use indicates that changes in PfCRT are deleterious to the parasite. Some CQR parasites, however, persist in the field and grow well in culture, which may reflect adaptive changes in the parasite genome to compensate for the mutations in PfCRT. Using three isogenic clones that have different drug resistance profiles corresponding to unique mutations in the pfcrt gene (106/1K76, 106/176I, and 106/76I-352K), we investigated changes in gene expression in these parasites grown with and without CQ. We also conducted hybridizations of genomic DNA to identify copy number (CN) changes in parasite genes. RNA transcript levels from 45 genes were significantly altered in one or both mutants relative to the parent line, 106/1K76. Most of the up-regulated genes are involved in invasion, cell growth and development, signal transduction, and transport activities. Of particular interest are genes encoding proteins involved in transport and/or regulation of cytoplasmic or compartmental pH such as the V-type H+ pumping pyrophosphatase 2 (PfVP2), Ca2+/H+ antiporter VCX1, a putative drug transporter and CN changes in pfmdr1. These changes may represent adaptations to altered functionality of PfCRT, a predicted member of drug/metabolite transporter superfamily found on the parasite food vacuole (FV) membrane. Further investigation of these genes may shed light on how the parasite compensates for functional changes accompanying drug resistance mutations in a gene coding for a membrane/drug transporter.
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Rosetting in Plasmodium falciparum: a cytoadherence phenotype with multiple actors. Transfus Clin Biol 2008; 15:62-71. [PMID: 18514562 DOI: 10.1016/j.tracli.2008.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 04/08/2008] [Indexed: 11/22/2022]
Abstract
The capacity of Plasmodium falciparum-infected red blood cells to bind uninfected red blood cells ("rosetting") has been associated with high parasite density in numerous geographic areas and with severe malaria in African children. We summarize here the associations that have emerged from field studies and describe the various experimental models of rosetting that have been developed. A variety of erythrocyte receptors, several serum factors and a number of rosette-mediating PfEMP1 adhesins have been identified. Several var genes code for rosette-forming PfEMP1 adhesins in each P. falciparum genome, so that each clonal line has the capacity to generate distinct types of rosettes. To clarify their respective role in malaria pathogenesis, each of the multiple ligand/receptor interactions should be further studied for fine specificity, binding affinity and the impact of the large population polymorphism of the parasite variant repertoires should be assessed. Interestingly, some major human erythrocyte surface polymorphisms have been identified as affecting rosette formation, consistent with a role for rosetting in life-threatening falciparum malaria.
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Chêne A, Donati D, Guerreiro-Cacais AO, Levitsky V, Chen Q, Falk KI, Orem J, Kironde F, Wahlgren M, Bejarano MT. A molecular link between malaria and Epstein-Barr virus reactivation. PLoS Pathog 2007; 3:e80. [PMID: 17559303 PMCID: PMC1891325 DOI: 10.1371/journal.ppat.0030080] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 04/19/2007] [Indexed: 02/06/2023] Open
Abstract
Although malaria and Epstein–Barr (EBV) infection are recognized cofactors in the genesis of endemic Burkitt lymphoma (BL), their relative contribution is not understood. BL, the most common paediatric cancer in equatorial Africa, is a high-grade B cell lymphoma characterized by c-myc translocation. EBV is a ubiquitous B lymphotropic virus that persists in a latent state after primary infection, and in Africa, most children have sero-converted by 3 y of age. Malaria infection profoundly affects the B cell compartment, inducing polyclonal activation and hyper-gammaglobulinemia. We recently identified the cystein-rich inter-domain region 1α (CIDR1α) of the Plasmodium falciparum membrane protein 1 as a polyclonal B cell activator that preferentially activates the memory compartment, where EBV is known to persist. Here, we have addressed the mechanisms of interaction between CIDR1α and EBV in the context of B cells. We show that CIDR1α binds to the EBV-positive B cell line Akata and increases the number of cells switching to the viral lytic cycle as measured by green fluorescent protein (GFP) expression driven by a lytic promoter. The virus production in CIDR1α-exposed cultures was directly proportional to the number of GFP-positive Akata cells (lytic EBV) and to the increased expression of the EBV lytic promoter BZLF1. Furthermore, CIDR1α stimulated the production of EBV in peripheral blood mononuclear cells derived from healthy donors and children with BL. Our results suggest that P. falciparum antigens such as CIDR1α can directly induce EBV reactivation during malaria infection that may increase the risk of BL development for children living in malaria-endemic areas. To our knowledge, this is the first report to show that a microbial protein can drive a latently infected B cell into EBV replication. Malaria and Epstein–Barr virus (EBV) infections are recognized cofactors in the genesis of endemic Burkitt lymphoma, the most common paediatric cancer in equatorial Africa. EBV is a ubiquitous virus residing in B lymphocytes that establishes a lifelong persistence in the host after primary infection. EBV has two lifestyles: latent infection (non-productive), and lytic replication (productive). Children living in malaria-endemic areas exhibit an elevated viral load, and acute malaria infection increases the levels of circulating EBV. The mechanisms leading to viral reactivation during Plasmodium falciparum malaria infection are not well understood. Cystein-rich inter-domain region 1α (CIDR1α) is a domain of a large protein expressed at the surface of P. falciparum–infected red blood cells. Based on previous findings showing that CIDR1α activates and expands the B cells compartment where EBV persists, we assessed the impact of CIDR1α on viral reactivation. Here, we identify CIDR1α as the first microbial protein able to drive a latently EBV-infected B cell (no virus production) into lytic replication (virus production). Our results suggest that P. falciparum–derived proteins can lead to a direct reactivation of EBV during acute malaria infection, increasing the risk of Burkitt lymphoma development for children living in malaria-endemic areas.
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MESH Headings
- Animals
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Antigens, Protozoan/metabolism
- Cell Line, Tumor
- Child
- Child, Preschool
- DNA, Viral/genetics
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Epstein-Barr Virus Infections/complications
- Erythrocytes/parasitology
- Gene Expression Regulation, Viral
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/immunology
- Humans
- Leukocytes, Mononuclear/virology
- Malaria/virology
- Plasmodium falciparum/genetics
- Plasmodium falciparum/immunology
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Protozoan Proteins/metabolism
- Recurrence
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Viral Proteins/genetics
- Viral Proteins/metabolism
- Virus Activation/genetics
- Virus Activation/immunology
- Virus Replication
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Affiliation(s)
- Arnaud Chêne
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Stockholm, Sweden
| | - Daria Donati
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
- * To whom correspondence should be addressed. E-mail:
| | | | - Victor Levitsky
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Qijun Chen
- Swedish Institute for Infectious Disease Control, Stockholm, Sweden
| | - Kerstin I Falk
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Stockholm, Sweden
| | | | - Fred Kironde
- Department of Biochemistry, Faculty of Medicine, Makerere University, Kampala, Uganda
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Stockholm, Sweden
| | - Maria Teresa Bejarano
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Ribacke U, Mok BW, Wirta V, Normark J, Lundeberg J, Kironde F, Egwang TG, Nilsson P, Wahlgren M. Genome wide gene amplifications and deletions in Plasmodium falciparum. Mol Biochem Parasitol 2007; 155:33-44. [PMID: 17599553 DOI: 10.1016/j.molbiopara.2007.05.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 04/13/2007] [Accepted: 05/15/2007] [Indexed: 11/24/2022]
Abstract
The extent to which duplications and deletions occur in the Plasmodium falciparum genome, outside of the subtelomeres, and their contribution to the virulence of the malaria parasite is not known. Here we show the presence of multiple genome wide copy number polymorphisms (CNPs) covering 82 genes, the most extensive spanning a cumulative size of 110kilobases. CNPs were identified in both laboratory strains and fresh clinical isolates using a 70-mer oligonucleotide microarray in conjunction with fluorescent in situ hybridizations and real-time quantitative PCR. The CNPs were found on all chromosomes except on chromosomes 6 and 8 and involved a total of 50 genes with increased copy numbers and 32 genes with decreased copy numbers relative to the 3D7 parasite. The genes, amplified in up to six copies, encode molecules involved in cell cycle regulation, cell division, drug resistance, erythrocyte invasion, sexual differentiation and unknown functions. These together with previous findings, suggest that the malaria parasite employs gene duplications and deletions as general strategies to enhance its survival and spread. Further analysis of the impact of discovered genetic differences and the underlying mechanisms is likely to generate a better understanding of the biology and the virulence of the malaria parasite.
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Affiliation(s)
- Ulf Ribacke
- Swedish Institute for Infectious Disease Control, SE-17182 Solna, Sweden
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30
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Xu L, Pei X, Berzins K, Chaudhuri A. Plasmodium yoelii: Experimental evidences for the conserved epitopes between mouse and human malaria parasite, Plasmodium falciparum. Exp Parasitol 2007; 116:214-24. [PMID: 17336297 DOI: 10.1016/j.exppara.2007.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 01/02/2007] [Accepted: 01/05/2007] [Indexed: 11/28/2022]
Abstract
Bioinformatic analyses of gene homologues have revealed functionally conserved epitopes between human and rodent malaria parasites. Here, we present experimental evidence for the presence of functionally and antigenically conserved domains between Plasmodium falciparum and Plasmodium yoelii asexual blood-stages. Merozoite released soluble proteins (MRSPs) from both P. falciparum and P. yoelii bound to heterologous mouse or human red blood cells, respectively. The presence of conserved antigenic epitopes between the two species of parasites was evident by the inhibitory effect of antibodies, developed against P. yoelii in convalescent mice, on P. falciparum growth and merozoite reinvasion in vitro. Furthermore, mice immunized with P. falciparum MRSPs were protected from infection by a P. yoelii challenge. These data indicate that different species of Plasmodium contain antigenically conserved interspecies domains, which are immunogenic and, thus constitute a potential novel antigen source for vaccine development and testing using a mouse model.
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Affiliation(s)
- Lili Xu
- Laboratory of Cell Biology, New York Blood Center, New York, NY 10021, USA
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31
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Abstract
In the century since the discovery of the ABO blood groups, numerous associations between ABO groups and disease have been noted. However, the selection pressures defining the ABO distributions remain uncertain. We review published information on Plasmodium falciparum infection and ABO blood groups. DNA sequence information dates the emergence and development of the group O allele to a period of evolution before human migration out of Africa, concomitant with P falciparum's activity. The current geographic distribution of group O is also consistent with a selection pressure by P falciparum in favor of group O individuals in malaria-endemic regions. We critically review clinical reports of ABO and P falciparum infection, documenting a correlation between disease severity and ABO group. Finally, we review published data on the pathogenesis of P falciparum infection, and propose a biologic model to summarize the role of ABO blood groups in cytoadherence biology. Such ABO-related mechanisms also point to a new hypothesis to account for selection of the Le(a-b-) phenotype. Taken together, a broad range of available evidence suggests that the origin, distribution, and relative proportion of ABO blood groups in humans may have been directly influenced by selective genetic pressure from P falciparum infection.
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Affiliation(s)
- Christine M Cserti
- University Health Network, Toronto General Hospital (Blood Transfusion Laboratory), Toronto, Ontario, Canada.
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32
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Luginbühl A, Nikolic M, Beck HP, Wahlgren M, Lutz HU. Complement factor D, albumin, and immunoglobulin G anti-band 3 protein antibodies mimic serum in promoting rosetting of malaria-infected red blood cells. Infect Immun 2007; 75:1771-7. [PMID: 17261605 PMCID: PMC1865670 DOI: 10.1128/iai.01514-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rosetting of Plasmodium falciparum-infected red blood cells (parasitized RBC [pRBC]) with uninfected RBC has been associated in many studies with malaria morbidity and is one form of cytoadherence observed with malarial parasites. Rosetting is serum dependent for many isolates of P. falciparum, including the strains FCR3S1.2 and Malayan Camp studied here. We identified the three naturally occurring components of sera which confer rosetting. Complement factor D alone induced 30 to 40% of de novo rosetting. Its effect was additive to that of 0.5 mg/ml albumin and to that of 15 ng/ml of naturally occurring antibodies to the anion transport protein, band 3. The three components together mediated rosetting as effectively as 10% serum. De novo rosetting experiments showed that naturally occurring anti-band 3 antibodies as well as factor D were effective only when added to pRBC. Factor D appeared to cleave a small fraction of a protein expressed on the surface of pRBC.
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Affiliation(s)
- Alexander Luginbühl
- ETH Zurich, Institute of Biochemistry, HPM D14, Schafmattstrasse 18, CH 8093 Zurich, Switzerland
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33
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Vogt AM, Pettersson F, Moll K, Jonsson C, Normark J, Ribacke U, Egwang TG, Ekre HP, Spillmann D, Chen Q, Wahlgren M. Release of sequestered malaria parasites upon injection of a glycosaminoglycan. PLoS Pathog 2006; 2:e100. [PMID: 17009869 PMCID: PMC1579244 DOI: 10.1371/journal.ppat.0020100] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 08/16/2006] [Indexed: 11/24/2022] Open
Abstract
Severe human malaria is attributable to an excessive sequestration of Plasmodium falciparum–infected and uninfected erythrocytes in vital organs. Strains of P. falciparum that form rosettes and employ heparan sulfate as a host receptor are associated with development of severe forms of malaria. Heparin, which is similar to heparan sulfate in that it is composed of the same building blocks, was previously used in the treatment of severe malaria, but it was discontinued due to the occurrence of serious side effects such as intracranial bleedings. Here we report to have depolymerized heparin by periodate treatment to generate novel glycans (dGAG) that lack anticoagulant-activity. The dGAGs disrupt rosettes, inhibit merozoite invasion of erythrocytes and endothelial binding of P. falciparum–infected erythrocytes in vitro, and reduce sequestration in in vivo models of severe malaria. An intravenous injection of dGAGs blocks up to 80% of infected erythrocytes from binding in the micro-vasculature of the rat and releases already sequestered parasites into circulation. P. falciparum–infected human erythrocytes that sequester in the non-human primate Macaca fascicularis were similarly found to be released in to the circulation upon a single injection of 500 μg of dGAG. We suggest dGAGs to be promising candidates for adjunct therapy in severe malaria. Severe Plasmodium falciparum malaria is common and in part the result of an excessive binding of infected erythrocytes in the microvasculature. The parasite employs heparan sulfate during the adherence to the vascular endothelium and to erythrocytes. Heparin, which is related to heparan sulfate in that it is composed of the same building blocks, was here periodate-treated to generate depolymerized glycosaminoglycans (dGAGs) that possess no anticoagulant activity. The dGAGs disrupt erythrocyte and endothelial binding of P. falciparum–infected erythrocytes in vitro. An intravenous injection of dGAGs blocks infected erythrocytes from binding in the micro-vasculature of the rat and releases already sequestrated parasites into circulation both in the rat and in a non-human primate. If this approach is successfully translated to the clinical setting, it may offer help to patients whereby the injection of a dGAG releases already sequestered parasite-infected erythrocytes and re-establishes the micro-vascular blood flow. The authors suggest dGAGs to be promising candidates of adjunct therapy that may have an important impact on malaria mortality.
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Affiliation(s)
- Anna M Vogt
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Fredrik Pettersson
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Cathrine Jonsson
- Department of Nuclear Medicine, Karolinska University Hospital, Solna, Sweden
| | - Johan Normark
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Ulf Ribacke
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | | | | | - Dorothe Spillmann
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Qijun Chen
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
- * To whom correspondence should be addressed. E-mail:
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34
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Kumar KA, Singh S, Babu PP. Studies on the glycoprotein modification in erythrocyte membrane during experimental cerebral malaria. Exp Parasitol 2006; 114:173-9. [PMID: 16753147 DOI: 10.1016/j.exppara.2006.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2005] [Revised: 03/06/2006] [Accepted: 03/08/2006] [Indexed: 10/24/2022]
Abstract
Plasmodium berghei ANKA (Pb ANKA) is a lethal strain of malaria that causes experimental cerebral malaria (ECM) in rodent models. Pathology of the disease is associated with the sequestration of the infected rbc (irbc) in the micro vessels of brain. In the present study, we analyzed the nature of the glycoprotein modification occurring in irbc membrane during erythrocytic stages of Pb ANKA infection. Titration of naturally occurring glycoproteins with concanavalin A (Con A) and wheat germ agglutinin (WGA) lectins revealed an enhanced lectin binding ability for the irbc membrane preparations. Partial characterization of the Con A specific determinants (alpha-d-methyl mannoside specificity) by lectin affinity chromatography followed by 2D electrophoresis and WGA specific determinants (sialic acid specificity) by Western analysis revealed the association of novel lectin specific determinants in irbc membrane. To correlate the biochemical changes with the morphological changes, SEM of irbc, and TEM of sequestered irbc were performed. These ultra structural studies revealed variable and irregular surface protrusions and deep surface indentations on irbc. These observations implicate that altered glycoprotein profiles may lead to cytoarchitectural changes in irbc membrane and such changes may be essential to establish contact with the host endothelial cells. These observations may be central to the microvascular sequestration and pathology of ECM.
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Affiliation(s)
- Kota Arun Kumar
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad-500 046, India
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35
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Moll K, Pettersson F, Vogt AM, Jonsson C, Rasti N, Ahuja S, Spångberg M, Mercereau-Puijalon O, Arnot DE, Wahlgren M, Chen Q. Generation of cross-protective antibodies against Plasmodium falciparum sequestration by immunization with an erythrocyte membrane protein 1-duffy binding-like 1 alpha domain. Infect Immun 2006; 75:211-9. [PMID: 17074852 PMCID: PMC1828381 DOI: 10.1128/iai.00749-06] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important virulence factor on the surface of infected erythrocytes. Naturally acquired antibodies to PfEMP1 expressed by parasites causing severe malaria are suggested to be protective and of major interest for the development of a vaccine against severe disease. In this study, the PfEMP1 expressed by a parasite clone displaying a multiadhesive phenotype associated with severe malaria was well recognized by sera of malaria semi-immune children. The efficiency of the Duffy binding-like 1 alpha (DBL1 alpha) domain of this PfEMP1 was therefore, alone or in combination with two additional DBL1 alpha domains, evaluated as a potential vaccine candidate using both a rodent model and a primate model. Antibodies against the DBL1 alpha domain were generated by immunization with recombinant DBL1 alpha-Semliki Forest virus particles and recombinant protein and analyzed in vitro. The immunized animals were challenged in vivo with various parasite strains or clones. Immunization with the PfEMP1-DBL1 alpha domain abolished the PfEMP1-dependent sequestration of the homologous strain in immunized rats and substantially inhibited parasite adhesion in immunized monkeys. Protection against sequestration of heterologous parasite strains was also confirmed by direct or indirect challenge in the rat model. These results strongly support the use of the DBL1 alpha domain in the development of a vaccine targeting severe malaria.
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Affiliation(s)
- Kirsten Moll
- Microbiology and Tumorbiology Center, Karolinska Institutet and Swedish Institute for Infectious Disease Control, Nobels väg 16, 171 77 Stockholm, Sweden
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36
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Pettersson F, Vogt AM, Jonsson C, Mok BW, Shamaei-Tousi A, Bergström S, Chen Q, Wahlgren M. Whole-body imaging of sequestration of Plasmodium falciparum in the rat. Infect Immun 2005; 73:7736-46. [PMID: 16239578 PMCID: PMC1273842 DOI: 10.1128/iai.73.11.7736-7746.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The occlusion of vessels by packed Plasmodium falciparum-infected (iRBC) and uninfected erythrocytes is a characteristic postmortem finding in the microvasculature of patients with severe malaria. Here we have employed immunocompetent Sprague-Dawley rats to establish sequestration in vivo. Human iRBC cultivated in vitro and purified in a single step over a magnet were labeled with 99mtechnetium, injected into the tail vein of the rat, and monitored dynamically for adhesion in the microvasculature using whole-body imaging or imaging of the lungs subsequent to surgical removal. iRBC of different lines and clones sequester avidly in vivo while uninfected erythrocytes did not. Histological examination revealed that a multiadhesive parasite adhered in the larger microvasculature, inducing extensive intravascular changes while CD36- and chondroitin sulfate A-specific parasites predominantly sequester in capillaries, inducing no or minor pathology. Removal of the adhesive ligand Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), preincubation of the iRBC with sera to PfEMP1 or preincubation with soluble PfEMP1-receptors prior to injection significantly reduced the sequestration. The specificity of iRBC binding to the heterologous murine receptors was confirmed in vitro, using primary rat lung endothelial cells and rat lung cryosections. In offering flow dynamics, nonmanipulated endothelial cells, and an intact immune system, we believe this syngeneic animal model to be an important complement to existing in vitro systems for the screening of vaccines and adjunct therapies aiming at the prevention and treatment of severe malaria.
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Affiliation(s)
- Fredrik Pettersson
- Microbiology & Tumorbiology Centre (MTC), Karolinska Institutet, Nobels väg 16, SE-171 77 Stockholm, Sweden
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37
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Cooke BM, Mohandas N, Cowman AF, Coppel RL. Cellular adhesive phenomena in apicomplexan parasites of red blood cells. Vet Parasitol 2005; 132:273-95. [PMID: 16087297 DOI: 10.1016/j.vetpar.2005.07.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The apicomplexan parasites Babesia and Plasmodium are related, yet phylogenetically distinct haemoprotozoa that infect red blood cells and cause severe diseases of major human and veterinary importance. A variety of cellular and molecular interactions are pivotal in many aspects of the pathogenicity of these two parasites. Comparison of the cellular and molecular mechanisms that culminate in accumulation of parasitised red blood cells in the microvasculature of cattle infected with Babesia bovis (babesiosis) and humans infected with Plasmodium falciparum (falciparum malaria) is particularly instructive given the striking similarities in the pathophysiology of these two important medical and veterinary diseases. While such adhesive phenomena have been studied extensively in malaria, they have received relatively little attention in babesiosis. In this review, we summarise the findings of more than 25 years of research into cellular adhesive phenomena in malaria and speculate on how this body of work can now be applied to Babesia parasites. Such information is fundamental if we are to learn more about the biology of Babesia parasites, the cellular and molecular mechanisms by which they cause infection and disease and how to develop novel therapeutic strategies or vaccines for both Babesia and malaria infections.
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Affiliation(s)
- Brian M Cooke
- Department of Microbiology, Monash University, Vic. 3800, Australia.
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38
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Cunningham DA, Jarra W, Koernig S, Fonager J, Fernandez-Reyes D, Blythe JE, Waller C, Preiser PR, Langhorne J. Host immunity modulates transcriptional changes in a multigene family (yir) of rodent malaria. Mol Microbiol 2005; 58:636-47. [PMID: 16238615 DOI: 10.1111/j.1365-2958.2005.04840.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Variant antigens, encoded by multigene families, and expressed at the surface of erythrocytes infected with the human malaria parasite Plasmodium falciparum and the simian parasite Plasmodium knowlesi, are important in evasion of host immunity. The vir multigene family, encoding a very large number of variant antigens, has been identified in the human parasite Plasmodium vivax and homologues (yir) of this family exist in the rodent parasite Plasmodium yoelii. These genes are part of a superfamily (pir) which are found in Plasmodium species infecting rodents, monkeys and humans (P. yoelii, P. berghei, P. chabaudi, P. knowlesi and P. vivax). Here, we show that YIR proteins are expressed on the surface of erythrocytes infected with late-stage asexual parasites, and that host immunity modulates transcription of yir genes. The surface location and expression pattern of YIR is consistent with a role in antigenic variation. This provides a unique opportunity to study the regulation and expression of the pir superfamily, and its role in both protective immunity and antigenic variation, in an easily accessible animal model system.
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Affiliation(s)
- Deirdre A Cunningham
- Division of Parasitology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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39
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Hodges M, Yikilmaz E, Patterson G, Kasvosve I, Rouault TA, Gordeuk VR, Loyevsky M. An iron regulatory-like protein expressed in Plasmodium falciparum displays aconitase activity. Mol Biochem Parasitol 2005; 143:29-38. [PMID: 15963579 DOI: 10.1016/j.molbiopara.2005.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 05/05/2005] [Indexed: 11/28/2022]
Abstract
Plasmodium falciparum iron regulatory-like protein (PfIRPa) has homology to both mammalian iron regulatory proteins and aconitases and is capable of binding RNA iron response elements. We examined the subcellular localization of PfIRPa and its enzymatic properties at low oxygen tension. Differential digitonin permeabilization of isolated trophozoites with subsequent Western blot analysis suggests that the localization of PfIRPa is predominantly in the membranous compartments of the parasite, such as the mitochondrion. Immunofluorescence analysis showed that PfIRPa colocalizes with heat shock protein 60 (Hsp60), a mitochondrial marker, and is also present in the parasitic cytosol/food vacuole. Under conditions favoring the formation of an iron-sulfur cluster, recombinant PfIRPa (rPfIRPa) had aconitase activity as detected by a colorimetric NADPH-MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay. As assessed by the hydration of cis-aconitate spectrophotometrically at 240 nm, rPfIRPa had high affinity for cis-aconitate (Km=3.5 microM) but a low turnover number (Kcat= 3.3 s(-1)). The overall catalytic efficiency (Kcat/Km) of rPfIRPa was similar in magnitude to human cytosolic IRP1/aconitase and human mitochondrial aconitase. PfIRPa immunoprecipitated from parasite lysates also had aconitase activity, as assessed by an MTT-based assay. Our results provide evidence that PfIRPa localizes in the mitochondrion and in the cytosol/food vacuole and is able to demonstrate aconitase activity. Further understanding of the role of PfIRPa/aconitase in the regulation of P. falciparum homeostasis may contribute towards the development of novel antimalarial strategies against plasmodial species.
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Affiliation(s)
- Marcus Hodges
- The Center for Sickle Cell Disease, Howard University, Washington, DC 20059, USA
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40
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Chen Q, Pettersson F, Vogt AM, Schmidt B, Ahuja S, Liljeström P, Wahlgren M. Immunization with PfEMP1-DBL1alpha generates antibodies that disrupt rosettes and protect against the sequestration of Plasmodium falciparum-infected erythrocytes. Vaccine 2004; 22:2701-12. [PMID: 15246600 DOI: 10.1016/j.vaccine.2004.02.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2003] [Revised: 01/30/2004] [Accepted: 02/03/2004] [Indexed: 10/26/2022]
Abstract
A family of parasite antigens known as Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is believed to play an important role in the binding of infected erythrocytes to host receptors in the micro-vasculature. Available data advocates the existence of a subset of very adhesive (rosetting, auto-agglutinating) and antigenic PfEMP1s implicated as virulence factors. Serum antibodies that disrupt rosettes are rarely found in children with severe malaria but are frequent in those with mild disease suggesting that they may be protective. Here we have developed a Semliki forest virus (SFV) vaccine construct with a recombinant gene (mini-var gene) encoding a mini-PfEMP1 (DBL1alpha-TM-ATS) obtained from a particularly antigenic and rosetting parasite (FCR3S1.2). The mini-PfEMP1 is presented to the host mimicking the location of the native molecule at the infected erythrocyte surface. Antibodies generated by a regimen of priming with SFV RNA particles and boosting with a recombinant protein recognize the infected erythrocyte surface (immuno-fluorescence/rosette-disruption) and prevent the sequestration of P. falciparum-infected erythrocytes in an in vivo model of severe malaria. The data prove the involvement of DBL1alpha in the adhesion of infected- and uninfected erythrocytes and the role of rosette-disruptive antibodies in preventing these cellular interactions. The work supports the use of DBL1alpha in a vaccine again severe malaria.
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Affiliation(s)
- Qijun Chen
- Microbiology and Tumorbiology Centre, Karolinska Institutet, Box 280, SE-171 77 Stockholm, Sweden.
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41
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Donati D, Zhang LP, Chêne A, Chen Q, Flick K, Nyström M, Wahlgren M, Bejarano MT. Identification of a polyclonal B-cell activator in Plasmodium falciparum. Infect Immun 2004; 72:5412-8. [PMID: 15322039 PMCID: PMC517431 DOI: 10.1128/iai.72.9.5412-5418.2004] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Polyclonal B-cell activation and hypergammaglobulinemia are prominent features of human malaria. We report here that Plasmodium falciparum-infected erythrocytes directly adhere to and activate peripheral blood B cells from nonimmune donors. The infected erythrocytes employ the cysteine-rich interdomain region 1alpha (CIDR1alpha) of P. falciparum erythrocyte membrane protein 1 (PfEMP1) to interact with the B cells. Stimulation with recombinant CIDR1alpha induces proliferation, an increase in B-cell size, expression of activation molecules, and secretion of immunoglobulins (immunoglobulin M) and cytokines (tumor necrosis factor alpha and interleukin-6). Furthermore, CIDR1alpha binds to Fab and Fc fragments of human immunoglobulins and to immunoglobulins purified from the sera of different animal species. This binding pattern is similar to that of the polyclonal B-cell activator Staphylococcus aureus protein A. Our findings shed light on the understanding of the molecular basis of polyclonal B-cell activation during malaria infections. The results suggest that the var gene family encoding PfEMP1 has evolved not only to mediate the sequestration of infected erythrocytes but also to manipulate the immune system to enhance the survival of the parasite.
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Affiliation(s)
- Daria Donati
- Microbiology and Tumorbiology Center, Karolinska Institutet, Stockholm, Sweden
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42
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Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important virulence factor encoded by a family of roughly 60 var genes and is used by the parasite to interact with the human host. The parasite regularly exchanges the expressed var gene generating antigenic variation of the infected RBCs (pRBC) surface which is crucial for successful proliferation and transmission. PfEMP1 is also an adhesive molecule that binds to an array of human receptors. By sequestration in the post-capillary venules, pRBCs are able to escape the spleen-mediated clearance but severe malaria may develop if the local binding is extensive. Anti-PfEMP1 immunity is important for preventing the development of both cerebral malaria and placental malaria, but more immunological studies on PfEMP1 antigens and their interaction with the human host are needed. Over the last few years our knowledge about var genes and PfEMP1s has increased dramatically through genetic, biochemical, immunological and epidemiological studies. In addition, the genome sequence has also provided us with a new platform for further dissecting its biological functions. This review highlights the recent analyses of var genes in the P. falciparum genome and postulates significance of genome recombination to the diversity of parasite virulence.
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Affiliation(s)
- Kirsten Flick
- Microbiology and Tumour Biology Centre (MTC), Karolinska Institutet and Swedish Institute for Infectious Disease Control, Box 280, SE-171 77 Stockholm, Sweden
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43
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Staalsoe T, Nielsen MA, Vestergaard LS, Jensen ATR, Theander TG, Hviid L. In vitro selection of Plasmodium falciparum 3D7 for expression of variant surface antigens associated with severe malaria in African children. Parasite Immunol 2004; 25:421-7. [PMID: 14651589 DOI: 10.1111/j.1365-3024.2003.00652.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
P. falciparum-infected red blood cells (IRBC) can adhere to endothelial host receptors through parasite-encoded, clonally variant surface antigens (VSA). The VSA-mediated IRBC adhesion and the acquired VSA-specific antibody response have both been linked to IRBC organ tropism and disease severity. Parasites isolated from young children with severe malaria (SM) tend to express a limited and conserved set of VSA (VSASM) that are both stronger and more commonly recognized by IgG in the plasma of malaria-exposed individuals than VSA (VSAUM) expressed by parasites causing uncomplicated malaria (UM) in older semi-immune children. Establishment of the genetic mechanism underlying changes in VSA expression in response to in vitro selective pressure is now possible because of the availability of the entire genomic sequence of the P. falciparum clone 3D7. As a first step towards direct molecular identification of VSASM-encoding genes in 3D7, we report here a method of enforcing expression of VSASM-like antigens in this parasite clone by a novel selection method using plasma from semi-immune children with low VSAUM-specific, but high VSASM-specific, IgG reactivity. In addition to the resulting increase in VSA-specific IgG recognition, VSASM-expressing 3D7(3D7-Dodowa1) showed reduced adhesion to CD36. Finally, levels of IgG specific for the VSA expressed by 3D7-Dodowa1 were uniformly higher than those of IgG with specificity for VSA expressed by the unselected 3D7 in plasma samples from geographically and epidemiologically diverse areas of endemic parasite transmission. The described selection method appears a useful tool in the identification of genes encoding VSA involved in severe and life-threatening P. falciparum malaria.
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MESH Headings
- Adolescent
- Adult
- Africa
- Animals
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- CD36 Antigens/physiology
- CHO Cells
- Cell Adhesion
- Child
- Cricetinae
- Erythrocytes/parasitology
- Erythrocytes/physiology
- Gene Expression
- Humans
- Immunoglobulin G/blood
- Malaria, Falciparum/epidemiology
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Middle Aged
- Plasmodium falciparum/genetics
- Plasmodium falciparum/immunology
- Selection, Genetic
- Variant Surface Glycoproteins, Trypanosoma/biosynthesis
- Variant Surface Glycoproteins, Trypanosoma/classification
- Variant Surface Glycoproteins, Trypanosoma/genetics
- Variant Surface Glycoproteins, Trypanosoma/immunology
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Affiliation(s)
- Trine Staalsoe
- Centre for Medical Parasitology at Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
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44
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Noviyanti R, Brown GV. Phenotypic switching and var gene transcription in Plasmodium falciparum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 531:149-59. [PMID: 12916787 DOI: 10.1007/978-1-4615-0059-9_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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45
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O'Dea KP, Pasvol G. Optimal tumor necrosis factor induction by Plasmodium falciparum requires the highly localized release of parasite products. Infect Immun 2003; 71:3155-64. [PMID: 12761094 PMCID: PMC155712 DOI: 10.1128/iai.71.6.3155-3164.2003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Overproduction of tumor necrosis factor (TNF) has been linked with the pathogenesis of Plasmodium falciparum malaria. Here, we examined why the high levels of TNF-inducing activity associated with P. falciparum-parasitized erythrocytes (PE) appear to be lost after cell lysis. Static coculture of PE and peripheral blood mononuclear cells (PBMC), with or without separation by porous membranes, demonstrated that rupture of live PE in the presence of responder cells was required for optimal TNF induction. Although the insoluble fraction of lysed PE was found to partially inhibit TNF responses, supernatants prepared from large numbers of lysed PE still contained only low levels of TNF-inducing activity, which showed no evidence of instability. A dramatic reduction in TNF levels resulted when noncytoadherent PE lines were maintained under low-cell-proximity conditions by suspension coculture. This reduction was much less marked with PE capable of adhering to PBMC, despite the fact that cytoadherent and noncytoadherent parasite lines induced comparable levels of TNF in high-cell-proximity, static coculture. These results suggest that rupture of PE in a highly localized setting, facilitated by either static coculture or the more biologically relevant phenomenon of cytoadherence to PBMC, can result in considerable enhancement of the P. falciparum-induced TNF response.
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Affiliation(s)
- Kieran P O'Dea
- Wellcome Centre for Clinical Tropical Medicine, Department of Infection and Tropical Medicine, Imperial College London, United Kingdom.
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46
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Winter G, Chen Q, Flick K, Kremsner P, Fernandez V, Wahlgren M. The 3D7var5.2 (var COMMON) type var gene family is commonly expressed in non-placental Plasmodium falciparum malaria. Mol Biochem Parasitol 2003; 127:179-91. [PMID: 12672527 DOI: 10.1016/s0166-6851(03)00004-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Relapse variants in chronic Plasmodium falciparum infections are antigenically distinct from the parental parasites. The variable antigen PfEMP1 expressed at the surface of the infected erythrocyte (IE) is encoded by the var gene family with approximately 60 copies per haploid genome. Placental isolates commonly express DBLgamma containing subtypes of var genes with homology to either 3D7var5.2 (var(COMMON)) or FCR3var(CSA). Here we report that var(COMMON) related genes are constitutively transcribed in approximately 60% of malaria infected children in Gabon. var(COMMON) is conserved in field isolates over at least 2.1kb. In 3D7 parasites var(COMMON) is present on chromosome 5 (var5.2) and constitutively transcribed in the opposite direction to most other var genes. It lacks a regulatory intron, an acidic terminal segment and ends in telomeric repeat sequences. var(COMMON) encodes a large, hypothetical PfEMP1 of a structure similar to previous placenta-binding PfEMP1s but it is not present at the IE-surface. IE of a 3D7 clone (3D7S8) transcribe var(COMMON) but express a PfEMP1 distinct from var(COMMON) at the surface and adhere to placental tissues through var(COMMON) independent novel mechanisms. Our report suggests that expression of var(COMMON) type genes is not restricted to placental malaria.
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Affiliation(s)
- Gerhard Winter
- Microbiology and Tumor Biology Center, Karolinska Institutet, P.O. Box 280, SE-171 77, Stockholm, Sweden
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47
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Miller SK, Good RT, Drew DR, Delorenzi M, Sanders PR, Hodder AN, Speed TP, Cowman AF, de Koning-Ward TF, Crabb BS. A subset of Plasmodium falciparum SERA genes are expressed and appear to play an important role in the erythrocytic cycle. J Biol Chem 2002; 277:47524-32. [PMID: 12228245 DOI: 10.1074/jbc.m206974200] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Plasmodium falciparum serine repeat antigen (SERA) has shown considerable promise as a blood stage vaccine for the control of malaria. A related protein, SERPH, has also been described in P. falciparum. Whereas their biological role remains unknown, both proteins possess papain-like protease domains that may provide attractive targets for therapeutic intervention. Genomic sequencing has recently shown that SERA and SERPH are the fifth and sixth genes, respectively, in a cluster of eight SERA homologues present on chromosome 2. In this paper, the expression and functional relevance of these eight genes and of a ninth SERA homologue found on chromosome 9 were examined in blood stage parasites. Using reverse transcriptase-PCR and microarray approaches, we demonstrate that whereas mRNA to all nine SERA genes is synthesized late in the erythrocytic cycle, it is those genes in the central region of the chromosome 2 cluster that are substantially up-regulated at this time. Using antibodies specific to each SERA, it was apparent that SERA4 to -6, and possibly also SERA9, are synthesized in blood stage parasites. The reactivity of antibodies from malaria-immune individuals with the SERA recombinant proteins suggested that SERA2 and SERA3 are also expressed at least in some parasite populations. To examine whether SERA genes are essential to blood stage growth, each of the eight chromosome 2 SERA genes was targeted for disruption. Whereas genes at the periphery of the cluster were mostly dispensable (SERA2 and -3 and SERA7 and -8), those in the central region (SERA4 to -6) could not be disrupted. The inability to disrupt SERA4, -5, and -6 is consistent with their apparent dominant expression and implies an important role for these genes in maintenance of the erythrocytic cycle.
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MESH Headings
- Animals
- Antigens, Protozoan/biosynthesis
- Antigens, Protozoan/genetics
- Blotting, Southern
- Blotting, Western
- Chromosomes
- DNA/metabolism
- Electrophoresis, Polyacrylamide Gel
- Erythrocytes/metabolism
- Erythrocytes/parasitology
- Female
- Fluorescent Antibody Technique, Indirect
- Glutathione Transferase/metabolism
- Mice
- Mice, Inbred BALB C
- Microscopy, Fluorescence
- Models, Genetic
- Multigene Family
- Oligonucleotide Array Sequence Analysis
- Plasmodium falciparum/genetics
- Plasmodium falciparum/metabolism
- Protein Structure, Tertiary
- Rabbits
- Recombinant Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Time Factors
- Transfection
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Affiliation(s)
- Susanne K Miller
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3050, Australia
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48
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Abstract
Plasmodium falciparum malaria remains as one of the most devastating global health problems of today. It is estimated that around 150 million individuals get the disease every year and of these 2-3 million die from it. Our knowledge of the mechanisms underlying the pathology has expanded greatly over the last decades, but many aspects of the molecular biology, immunology and epidemiology that govern the pathogenesis and spread of this parasite are still unclear. As new insights are gained we are also revealing a challenging biological complexity. Piecing this information together is the key to vaccine development and production of new antimalarial drugs.
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Affiliation(s)
- Andreas Heddini
- Microbiology and Tumor Biology Center, Karolinska Institutet and Swedish Institute for Infectious Disease Control, Stockholm, Sweden.
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49
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Afonso Nogueira P, Wunderlich G, Shugiro Tada M, d'Arc Neves Costa J, José Menezes M, Scherf A, Pereira-da-Silva LH. Plasmodium falciparum: analysis of transcribed var gene sequences in natural isolates from the Brazilian Amazon region. Exp Parasitol 2002; 101:111-20. [PMID: 12427465 DOI: 10.1016/s0014-4894(02)00107-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Parasite isolates from Brazilian Western Amazonian patients suffering from uncomplicated falciparum malaria were matured in vitro and their var gene transcripts were analysed by RT-PCR and sequencing. Additionally, the cytoadherence patterns of these isolates were determined by panning techniques using transfected CHO cell lines expressing different surface receptors. All of the isolates tested showed between 4 and 13 different var gene transcripts per isolate. Several of these transcripts were present in more than one isolate and three sequences appeared to be preferentially expressed in natural infections. In most of the isolates, cytoadherence occurred to the receptors ICAM-1 and CD36. Several isolates showed a multiadherent profile. Analysis of MSP1 and MSP2 allelic polymorphism indicated polyclonal infections, that could be responsible for the multiadherent phenotype.
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Affiliation(s)
- Paulo Afonso Nogueira
- Centro de Pesquisa em Medicina Tropical, CP 87, Correio Central, 78.910-210 Porto Velho, Rondônia, Brazil
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50
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Fernandez V, Chen Q, Sundström A, Scherf A, Hagblom P, Wahlgren M. Mosaic-like transcription of var genes in single Plasmodium falciparum parasites. Mol Biochem Parasitol 2002; 121:195-203. [PMID: 12034453 DOI: 10.1016/s0166-6851(02)00038-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The var gene family of Plasmodium falciparum encodes the clonally variant adhesin PfEMP1 present on the surface of infected erythrocytes. A poorly understood mechanism of allelic exclusion controls the expression of PfEMP1. Transcription of var genes is developmentally and, most likely, epigenetically regulated. Here we have studied the transcriptional pattern of 28 members of this multigene family in individual parasites, early in the intraerythrocytic cycle. The results show unique patterns (type and number) of var transcripts in each individual PRBC, with 1-15 mRNA species detected per cell at 2-4 h post-invasion. When a panel of ten single PRBC was analyzed, the var gene coding for the expressed PfEMP1 was transcribed in more cells than any other, although transcripts from this gene did not give the strongest hybridization signal within each individual cell. Chromosomal mapping of transcriptionally active var genes indicated that their distribution reflects that of var loci in the genome, including a pronounced clustering in chromosome 4. These findings, taken together with existing data on var transcription at later developmental stages, suggest that the mosaic-like transcription of multiple var genes detected at the ring stage and the steady transcription of the gene encoding the expressed PfEMP1 are distinct although superimposed events, one of them random and the other taking place under some form of imprinting. With its unique features, the expression of P. falciparum var genes may reveal new principles of gene regulation.
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Affiliation(s)
- Victor Fernandez
- Microbiology and Tumor Biology Center, Karolinska Institutet and Swedish Institute for Infectious Disease Control, Box 280, S-17177 Stockholm, Sweden.
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