scholarly journals Cross-Reactive Surface Epitopes on Chondroitin Sulfate A-Adherent Plasmodium falciparum-Infected Erythrocytes Are Associated with Transcription of var2csa

2005 ◽  
Vol 73 (5) ◽  
pp. 2848-2856 ◽  
Author(s):  
Salenna R. Elliott ◽  
Michael F. Duffy ◽  
Timothy J. Byrne ◽  
James G. Beeson ◽  
Emily J. Mann ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Chondroitin Sulfate ◽  
Erythrocyte Membrane ◽  
Cell Sorting ◽  
Rabbit Antiserum ◽  
Fluorescence Activated Cell Sorting ◽  
Parasite Protein ◽  
Chondroitin Sulfate A ◽  
In Pregnancy

ABSTRACT Malaria in pregnancy is associated with placental accumulation of Plasmodium falciparum-infected erythrocytes (IE) that adhere to chondroitin sulfate A (CSA). Adhesion is mediated by P. falciparum erythrocyte membrane protein 1 (PfEMP1), a variant parasite protein expressed on the surface of IE and encoded by var genes. Rabbit antiserum was generated against the CSA-adherent P. falciparum line CS2, in which the dominant var transcribed is var2csa, a relatively conserved var gene that has been associated with CSA adhesion. Anti-CS2 recognized genetically distinct CSA-adherent P. falciparum lines but not CD36-adherent parent lines. Reactivity with anti-CS2 correlated with the level of adhesion to CSA. Fluorescence-activated cell sorting according to binding of anti-CS2 showed reactivity was associated with CSA adhesion and transcription of var2csa. These data are consistent with the hypothesis that var2csa encodes a PfEMP1 expressed on the surface of IE, which mediates adhesion to CSA and is relatively conserved between genetically distinct strains of P. falciparum.

scholarly journals Neonatal and Maternal Immunological Responses to Conserved Epitopes within the DBL-γ3 Chondroitin Sulfate A-Binding Domain of Plasmodium falciparum Erythrocyte Membrane Protein 1

2005 ◽  
Vol 73 (12) ◽  
pp. 7988-7995 ◽  
Author(s):  
Kim Brustoski ◽  
Martin Kramer ◽  
Ulrike Möller ◽  
Peter G. Kremsner ◽  
Adrian J. F. Luty
Keyword(s):  
T Cells ◽  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Chondroitin Sulfate ◽  
Erythrocyte Membrane ◽  
Venous Blood ◽  
Binding Domain ◽  
Erythrocyte Membrane Protein ◽  
Conserved Regions ◽  
Chondroitin Sulfate A

ABSTRACT Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) mediates the adherence of P. falciparum-infected erythrocytes to placental syncytiotrophoblasts via interactions with chondroitin sulfate A (CSA), a characteristic of pregnancy-associated malaria. Pregnancy-associated malaria predicts increased susceptibility of newborns to malaria, and it is postulated that transplacental passage of parasite antigen induces immune regulatory activity in the neonate. We wished to examine the immune responsiveness to a CSA-binding domain of PfEMP1, the DBL-γ3 domain, in cord and maternal venous blood obtained from pregnancies with various histories of P. falciparum infection. We assessed in vitro T-cell cytokine and plasma immunoglobulin G (IgG) and IgM responses to four peptides corresponding to highly conserved regions of a DBL-γ3 domain common to central African parasite isolates. The presence of placental P. falciparum infection at delivery was associated with elevated frequencies of DBL-γ3 peptide-specific CD3+ interleukin-10-positive T cells in cord blood, while treatment and clearance of infection prior to delivery was associated with elevated frequencies of CD3+ gamma interferon-positive T cells. DBL-γ3 peptide-specific IgM antibodies were detected in 12 of 60 (20%) cord plasma samples from those born to mothers with P. falciparum infection during pregnancy. Consistent with polyclonal anti-PfEMP1 antibody responses that are associated with protection against pregnancy-associated malaria, the presence of maternal IgG antibodies with specificity for one of the DBL-γ3 peptides showed a parity-dependent profile. These data demonstrate that peptides corresponding to conserved regions of the DBL-γ3 domain of PfEMP1 are immunogenic in P. falciparum-infected mothers and their offspring.

scholarly journals Identification of Glycosaminoglycan Binding Domains in Plasmodium falciparum Erythrocyte Membrane Protein 1 of a Chondroitin Sulfate A-Adherent Parasite

2000 ◽  
Vol 68 (7) ◽  
pp. 3923-3926 ◽  
Author(s):  
John C. Reeder ◽  
Anthony N. Hodder ◽  
James G. Beeson ◽  
Graham V. Brown
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Chondroitin Sulfate ◽  
Erythrocyte Membrane ◽  
Binding Activity ◽  
Parasite Line ◽  
Erythrocyte Membrane Protein ◽  
Binding Domains ◽  
Nonlinear Binding ◽  
Chondroitin Sulfate A

ABSTRACT Accumulation of Plasmodium falciparum-infected erythrocytes in the placenta is a key feature of maternal malaria. This process is mediated in part by the parasite ligand P. falciparum erythrocyte membrane protein 1 (PfEMP1) at the surface of the infected erythrocyte interacting with the host receptor chondroitin sulfate A (CSA) on the placental lining. We have localized CSA binding activity to two adjacent domains in PfEMP1 of an adherent parasite line and shown the presence of at least three active glycosaminoglycan binding sites. A putative CSA binding sequence was identified in one domain, but nonlinear binding motifs are also likely to be present, since binding activity in the region was shown to be dependent on conformation. Characterization of this binding region provides an opportunity to investigate further its potential as a target for antiadhesion therapy.

Plasmodium falciparum erythrocyte membrane protein 1 functions as a ligand for P-selectin

Blood ◽  
2001 ◽  
Vol 98 (10) ◽  
pp. 3132-3135 ◽  
Author(s):  
Anna M. Senczuk ◽  
John C. Reeder ◽  
Magda M. Kosmala ◽  
May Ho
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Adhesion Molecule ◽  
Affinity Purification ◽  
Intercellular Adhesion Molecule ◽  
Microvascular Endothelium ◽  
Parasite Protein ◽  
Erythrocyte Membrane Protein ◽  
Falciparum Erythrocyte Membrane Protein

Abstract The malarial protein Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a parasite protein that is exported to the surface of the infected erythrocyte, where it is inserted into the red cell cytoskeleton in the second half of the parasite life cycle. The surface expression of PfEMP1 coincides with the occurrence of the adhesion of infected erythrocytes to vascular endothelium. This protein has been shown to interact with CD36, intercellular adhesion molecule-1 (ICAM-1) and chondroitin sulfate A (CSA). In this study, it is demonstrated by affinity purification and western blot analysis that PfEMP1 also functions as a cell surface ligand for P-selectin, an adhesion molecule that has been shown to mediate the rolling of infected erythrocytes under physiologic flow conditions, leading to a significant increase in adhesion to CD36 on activated platelets and microvascular endothelium.

scholarly journals Conservation of single amino-acid polymorphisms in Plasmodium falciparum erythrocyte membrane protein 1 and association with severe pathophysiology

2017 ◽  
Author(s):  
Daniel Zinder ◽  
Mary M. Rorick ◽  
Kathryn E. Tiedje ◽  
Shazia Ruybal-Pesántez ◽  
Karen P. Day ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasmodium Falciparum ◽  
Amino Acid ◽  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Severe Disease ◽  
Single Amino Acid ◽  
Sequence Motifs ◽  
Parasite Protein ◽  
Erythrocyte Membrane Protein

ABSTRACTPlasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a parasite protein encoded by a multigene family known as var. Expressed on the surface of infected red blood cells, PfEMP1 plays a central role in parasite virulence. The DBLα domain of PfEMP1 contains short sequence motifs termed homology blocks. Variation within homology blocks, at the level of single amino-acid modifications, has not been considered before in association with severe disease. Here we identify a total of 2701 amino-acid polymorphisms within DBLα homology blocks, the majority of which are shared between two geographically distant study populations in existing transcription data from Kenya and in a new genomic dataset sampled in Ghana. Parasitemia levels and the transcription levels of specific polymorphisms are as predictive of severe disease (AUC=0.83) and of the degree of rosetting (forecast skill SS=0.45) as the transcription of classic var groups. 11 newly categorized polymorphisms were strongly correlated with grpA var gene expression (SS=0.93) and a different set of 16 polymorphisms was associated with the H3 subset (SS=0.20). These associations provide the basis for a novel method of relating pathophysiology to parasite gene expression levels—one that, being site-specific, has more molecular detail than previous models based on var groups or homology blocks. This newly described variation influences disease outcome, and can help develop anti-malarial intervention strategies such as vaccines that target severe disease. Further replication of this analysis in geographically disparate populations and for larger sample sizes can help improve the identification of the molecular causes of severe disease.

scholarly journals Identification of VAR2CSA Domain-Specific Inhibitory Antibodies of the Plasmodium falciparum Erythrocyte Membrane Protein 1 Using a Novel Flow Cytometry Assay

2013 ◽  
Vol 20 (3) ◽  
pp. 433-442 ◽  
Author(s):  
Harold Obiakor ◽  
Marion Avril ◽  
Nicholas J. MacDonald ◽  
Prakash Srinivasan ◽  
Karine Reiter ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Chondroitin Sulfate ◽  
Erythrocyte Membrane ◽  
Recombinant Proteins ◽  
Binding Assay ◽  
Content Type ◽  
Erythrocyte Membrane Protein ◽  
First Time

ABSTRACTVAR2CSA, a member of thePlasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) family, is a leading candidate for use in vaccines to protect first-time mothers from placental malaria (PM). VAR2CSA, which is comprised of a series of six Duffy binding-like (DBL) domains, binds chondroitin sulfate A (CSA) on placental syncytiotrophoblast. Several recombinant DBL domains have been shown to bind CSA. In order to identify and develop recombinant proteins suitable for clinical development, DBL2X and DBL3X, as well as their respective third subdomain (S3) from the FCR3 parasite clone, were expressed inEscherichia coli, refolded, and purified. All but DBL3X-S3 recombinant proteins bound to CSA expressed on Chinese hamster ovary (CHO)-K1 cells but not to CHO-pgsA745 cells, which are CSA negative as determined by flow cytometry. All but DBL3X-S3 bound to CSA on chondroitin sulfate proteoglycan (CSPG) as determined by surface plasmon resonance (SPR) analysis. Purified IgG from rats and rabbits immunized with these four recombinant proteins bound homologous and some heterologous parasite-infected erythrocytes (IE). Using a novel flow cytometry inhibition-of-binding assay (flow-IBA), antibodies against DBL3X-S3 inhibited 35% and 45% of IE binding to CSA on CHO-K1 cells compared to results for soluble CSA (sCSA) and purified multigravida (MG) IgG, respectively, from areas in Tanzania to which malaria is endemic. Antibodies generated against the other domains provided little or no inhibition of IE binding to CSA on CHO-K1 cells as determined by the flow cytometry inhibition-of-binding assay. These results demonstrate for the first time the ability to identify antibodies to VAR2CSA DBL domains and subdomains capable of inhibiting VAR2CSA parasite-IE binding to CSA by flow cytometry. The flow cytometry inhibition-of-binding assay was robust and provided an accurate, reproducible, and reliable means to identify blocking of IE binding to CSA and promises to be significant in the development of a vaccine to protect pregnant women.

scholarly journals Nonspecific Immunoglobulin M Binding and Chondroitin Sulfate A Binding Are Linked Phenotypes of Plasmodium falciparum Isolates Implicated in Malaria during Pregnancy

2003 ◽  
Vol 71 (8) ◽  
pp. 4767-4771 ◽  
Author(s):  
Alison M. Creasey ◽  
Trine Staalsoe ◽  
Ahmed Raza ◽  
David E. Arnot ◽  
J. Alexandra Rowe
Keyword(s):  
Plasmodium Falciparum ◽  
Chondroitin Sulfate ◽  
Blood Cells ◽  
Immunoglobulin M ◽  
Wide Range ◽  
Malaria During Pregnancy ◽  
Normal Human ◽  
Immunological Assays ◽  
Chondroitin Sulfate A ◽  
In Pregnancy

ABSTRACT Binding of immunoglobulin M (IgM) antibodies from normal human serum to the surface of Plasmodium falciparum-infected red blood cells (iRBC) has previously been demonstrated only in parasites that form rosettes with uninfected red cells. We show that natural, nonspecific IgM but not IgG, IgA, IgD, or IgE also binds to the surface of iRBC selected for adhesion to chondroitin sulfate A (CSA), a placental receptor for parasites associated with malaria in pregnancy. The protease sensitivity of IgM-binding appears to match that of CSA binding, suggesting that the two phenotypes may be mediated by the same parasite molecule. We also show that a wide range of mouse monoclonal antibodies of the IgM class bind nonspecifically to CSA-selected iRBC, an important consideration in the interpretation of immunological assays performed on these parasite lines.

scholarly journals IgG acquisition against PfEMP1 PF11_0521 domain cassette DC13, DBLβ3_D4 domain, and peptides located within these constructs in children with cerebral malaria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cyril Badaut ◽  
Pimnitah Visitdesotrakul ◽  
Aurélie Chabry ◽  
Pascal Bigey ◽  
Bernard Tornyigah ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Hospital Admission ◽  
Cerebral Malaria ◽  
Erythrocyte Membrane ◽  
Uncomplicated Malaria ◽  
Clinical Status ◽  
Severe Anemia ◽  
Specific Interactions ◽  
Time Of Admission

AbstractThe Plasmodium falciparum erythrocyte-membrane-protein-1 (PF3D7_1150400/PF11_0521) contains both domain cassette DC13 and DBLβ3 domain binding to EPCR and ICAM-1 receptors, respectively. This type of PfEMP1 proteins with dual binding specificity mediate specific interactions with brain micro-vessels endothelium leading to the development of cerebral malaria (CM). Using plasma collected from children at time of hospital admission and after 30 days, we study an acquisition of IgG response to PF3D7_1150400/PF11_0521 DC13 and DBLβ3_D4 recombinant constructs, and five peptides located within these constructs, specifically in DBLα1.7_D2 and DBLβ3_D4 domains. We found significant IgG responses against the entire DC13, PF11_0521_DBLβ3_D4 domain, and peptides. The responses varied against different peptides and depended on the clinical status of children. The response was stronger at day 30, and mostly did not differ between CM and uncomplicated malaria (UM) groups. Specifically, the DBLβ3 B3-34 peptide that contains essential residues involved in the interaction between PF11_0521 DBLβ3_D4 domain and ICAM-1 receptor demonstrated significant increase in reactivity to IgG1 and IgG3 antibodies at convalescence. Further, IgG reactivity in CM group at time of admission against functionally active (ICAM-1-binding) PF11_0521 DBLβ3_D4 domain was associated with protection against severe anemia. These results support development of vaccine based on the PF3D7_1150400/PF11_0521 structures to prevent CM.

Identifying targets of protective antibodies against severe malaria in Papua, Indonesia using locally expressed domains of Plasmodium falciparum Erythrocyte Membrane Protein 1.

2021 ◽  
Author(s):  
Janavi S Rambhatla ◽  
Gerry Q Tonkin-Hill ◽  
Eizo Takashima ◽  
Takafumi Tsuboi ◽  
Rintis Noviyanti ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Severe Malaria ◽  
Erythrocyte Membrane ◽  
Uncomplicated Malaria ◽  
Igg Antibodies ◽  
Erythrocyte Membrane Protein ◽  
African Children ◽  
Genes Encoding ◽  
Malaria Severity

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), a diverse family of multi-domain proteins expressed on the surface of malaria-infected erythrocytes, is an important target of protective immunity against malaria. Our group recently studied transcription of the var genes encoding PfEMP1 in individuals from Papua, Indonesia with severe or uncomplicated malaria. We cloned and expressed domains from 32 PfEMP1s including 22 that were upregulated in severe malaria and 10 that were upregulated in uncomplicated malaria, using a wheat germ cell-free expression system. We used Luminex technology to measure IgG antibodies to these 32 domains and control proteins in 63 individuals (11 children). At presentation to hospital, levels of antibodies to PfEMP1 domains were either higher in uncomplicated malaria or were not significantly different between groups. Using principal components analysis, antibodies to three of 32 domains were highly discriminatory between groups. These included two domains upregulated in severe malaria, a DBLβ13 domain and a CIDRα1.6 domain (which has been previously implicated in severe malaria pathogenesis), and a DBLδ domain that was upregulated in uncomplicated malaria. Antibody to control non-PfEMP1 antigens did not differ with disease severity. Antibodies to PfEMP1 domains differ with malaria severity. Lack of antibodies to locally expressed PfEMP1 types, including both domains previously associated with severe malaria and newly identified targets, may in part explain malaria severity in Papuan adults. Importance Severe Plasmodium falciparum malaria kills many African children, and lack of antibody immunity predisposes to severe disease. A critical antibody target is the P. falciparum erythrocyte membrane 1 (PfEMP1) family of multidomain proteins, which are expressed on the infected erythrocyte surface and mediate parasite sequestration in deep organs. We previously identified var genes encoding PfEMP1 that were differentially expressed between severe and uncomplicated malaria in Papua, Indonesia. Here, we have expressed domains from 32 of these PfEMP1s and measured IgG antibody responses to them in Papuan adults and children. Using Principal Component Analysis, IgG antibodies to three domains distinguished between severe and uncomplicated malaria and were higher in uncomplicated malaria. Domains included CIDRα1.6, implicated in severe malaria; a DBLβ13 domain; and a DBLδ domain of unknown function. Immunity to locally relevant PfEMP1 domains may protect from severe malaria. Targets of immunity show important overlap between Asian adults and African children.

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