Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA

Mafalda Resende, Morten A. Nielsen, Madeleine Dahlbaeck, Sisse B. Ditlev, Pernille Andersen, Adam F. Sander, Nicaise T. Ndam, Thor G. Theander, Ali Salanti

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    Background: Pregnancy malaria is caused by Plasmodium falciparum-infected erythrocytes binding the placental receptor chondroitin sulfate A (CSA). This results in accumulation of parasites in the placenta with severe clinical consequences for the mother and her unborn child. Women become resistant to placental malaria as antibodies are acquired which specifically target the surface of infected erythrocytes binding in the placenta. VAR2CSA is most likely the parasite-encoded protein which mediates binding to the placental receptor CSA. Several domains have been shown to bind CSA in vitro; and it is apparent that a VAR2CSA-based vaccine cannot accommodate all the CSA binding domains and serovariants. It is thus of high priority to define minimal ligand binding regions throughout the VAR2CSA molecule. Methods: To define minimal CSA-binding regions/peptides of VAR2CSA, a phage display library based on the entire var2csa coding region was constructed. This library was screened on immobilized CSA and cells expressing CSA resulting in a limited number of CSA-binding phages. Antibodies against these peptides were affinity purified and tested for reactivity against CSA-binding infected erythrocytes. Results: The most frequently identified phages expressed peptides residing in the parts of VAR2CSA previously defined as CSA binding. In addition, most of the binding regions mapped to surface-exposed parts of VAR2CSA. The binding of a DBL2X peptide to CSA was confirmed with a synthetic peptide. Antibodies against a CSA-binding DBL2X peptide reacted with the surface of infected erythrocytes indicating that this epitope is accessible for antibodies on native VAR2CSA on infected erythrocytes. Conclusion: Short continuous regions of VAR2CSA with affinity for multiple types of CSA were defined. A number of these regions localize to CSA-binding domains and to surface-exposed regions within these domains and a synthetic peptide corresponding to a peptide sequence in DBL2 was shown to bind to CSA and not to CSC. It is likely that some of these epitopes are involved in native parasite CSA adhesion. However, antibodies directed against single epitopes did not inhibit parasite adhesion. This study supports phage display as a technique to identify CSA-binding regions of large proteins such as VAR2CSA.
    Original languageEnglish
    JournalMalaria Journal
    Volume7
    Issue number104
    ISSN1475-2875
    DOIs
    Publication statusPublished - 2008

    Cite this

    Resende, M., Nielsen, M. A., Dahlbaeck, M., Ditlev, S. B., Andersen, P., Sander, A. F., ... Salanti, A. (2008). Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA. Malaria Journal, 7(104). https://doi.org/10.1186/1475-2875-7-104
    Resende, Mafalda ; Nielsen, Morten A. ; Dahlbaeck, Madeleine ; Ditlev, Sisse B. ; Andersen, Pernille ; Sander, Adam F. ; Ndam, Nicaise T. ; Theander, Thor G. ; Salanti, Ali. / Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA. In: Malaria Journal. 2008 ; Vol. 7, No. 104.
    @article{edcce451fe11442ebfa98e80345d2cc5,
    title = "Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA",
    abstract = "Background: Pregnancy malaria is caused by Plasmodium falciparum-infected erythrocytes binding the placental receptor chondroitin sulfate A (CSA). This results in accumulation of parasites in the placenta with severe clinical consequences for the mother and her unborn child. Women become resistant to placental malaria as antibodies are acquired which specifically target the surface of infected erythrocytes binding in the placenta. VAR2CSA is most likely the parasite-encoded protein which mediates binding to the placental receptor CSA. Several domains have been shown to bind CSA in vitro; and it is apparent that a VAR2CSA-based vaccine cannot accommodate all the CSA binding domains and serovariants. It is thus of high priority to define minimal ligand binding regions throughout the VAR2CSA molecule. Methods: To define minimal CSA-binding regions/peptides of VAR2CSA, a phage display library based on the entire var2csa coding region was constructed. This library was screened on immobilized CSA and cells expressing CSA resulting in a limited number of CSA-binding phages. Antibodies against these peptides were affinity purified and tested for reactivity against CSA-binding infected erythrocytes. Results: The most frequently identified phages expressed peptides residing in the parts of VAR2CSA previously defined as CSA binding. In addition, most of the binding regions mapped to surface-exposed parts of VAR2CSA. The binding of a DBL2X peptide to CSA was confirmed with a synthetic peptide. Antibodies against a CSA-binding DBL2X peptide reacted with the surface of infected erythrocytes indicating that this epitope is accessible for antibodies on native VAR2CSA on infected erythrocytes. Conclusion: Short continuous regions of VAR2CSA with affinity for multiple types of CSA were defined. A number of these regions localize to CSA-binding domains and to surface-exposed regions within these domains and a synthetic peptide corresponding to a peptide sequence in DBL2 was shown to bind to CSA and not to CSC. It is likely that some of these epitopes are involved in native parasite CSA adhesion. However, antibodies directed against single epitopes did not inhibit parasite adhesion. This study supports phage display as a technique to identify CSA-binding regions of large proteins such as VAR2CSA.",
    author = "Mafalda Resende and Nielsen, {Morten A.} and Madeleine Dahlbaeck and Ditlev, {Sisse B.} and Pernille Andersen and Sander, {Adam F.} and Ndam, {Nicaise T.} and Theander, {Thor G.} and Ali Salanti",
    year = "2008",
    doi = "10.1186/1475-2875-7-104",
    language = "English",
    volume = "7",
    journal = "Malaria Journal",
    issn = "1475-2875",
    publisher = "BioMed Central",
    number = "104",

    }

    Resende, M, Nielsen, MA, Dahlbaeck, M, Ditlev, SB, Andersen, P, Sander, AF, Ndam, NT, Theander, TG & Salanti, A 2008, 'Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA', Malaria Journal, vol. 7, no. 104. https://doi.org/10.1186/1475-2875-7-104

    Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA. / Resende, Mafalda; Nielsen, Morten A.; Dahlbaeck, Madeleine; Ditlev, Sisse B.; Andersen, Pernille; Sander, Adam F.; Ndam, Nicaise T.; Theander, Thor G.; Salanti, Ali.

    In: Malaria Journal, Vol. 7, No. 104, 2008.

    Research output: Contribution to journalJournal articleResearchpeer-review

    TY - JOUR

    T1 - Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA

    AU - Resende, Mafalda

    AU - Nielsen, Morten A.

    AU - Dahlbaeck, Madeleine

    AU - Ditlev, Sisse B.

    AU - Andersen, Pernille

    AU - Sander, Adam F.

    AU - Ndam, Nicaise T.

    AU - Theander, Thor G.

    AU - Salanti, Ali

    PY - 2008

    Y1 - 2008

    N2 - Background: Pregnancy malaria is caused by Plasmodium falciparum-infected erythrocytes binding the placental receptor chondroitin sulfate A (CSA). This results in accumulation of parasites in the placenta with severe clinical consequences for the mother and her unborn child. Women become resistant to placental malaria as antibodies are acquired which specifically target the surface of infected erythrocytes binding in the placenta. VAR2CSA is most likely the parasite-encoded protein which mediates binding to the placental receptor CSA. Several domains have been shown to bind CSA in vitro; and it is apparent that a VAR2CSA-based vaccine cannot accommodate all the CSA binding domains and serovariants. It is thus of high priority to define minimal ligand binding regions throughout the VAR2CSA molecule. Methods: To define minimal CSA-binding regions/peptides of VAR2CSA, a phage display library based on the entire var2csa coding region was constructed. This library was screened on immobilized CSA and cells expressing CSA resulting in a limited number of CSA-binding phages. Antibodies against these peptides were affinity purified and tested for reactivity against CSA-binding infected erythrocytes. Results: The most frequently identified phages expressed peptides residing in the parts of VAR2CSA previously defined as CSA binding. In addition, most of the binding regions mapped to surface-exposed parts of VAR2CSA. The binding of a DBL2X peptide to CSA was confirmed with a synthetic peptide. Antibodies against a CSA-binding DBL2X peptide reacted with the surface of infected erythrocytes indicating that this epitope is accessible for antibodies on native VAR2CSA on infected erythrocytes. Conclusion: Short continuous regions of VAR2CSA with affinity for multiple types of CSA were defined. A number of these regions localize to CSA-binding domains and to surface-exposed regions within these domains and a synthetic peptide corresponding to a peptide sequence in DBL2 was shown to bind to CSA and not to CSC. It is likely that some of these epitopes are involved in native parasite CSA adhesion. However, antibodies directed against single epitopes did not inhibit parasite adhesion. This study supports phage display as a technique to identify CSA-binding regions of large proteins such as VAR2CSA.

    AB - Background: Pregnancy malaria is caused by Plasmodium falciparum-infected erythrocytes binding the placental receptor chondroitin sulfate A (CSA). This results in accumulation of parasites in the placenta with severe clinical consequences for the mother and her unborn child. Women become resistant to placental malaria as antibodies are acquired which specifically target the surface of infected erythrocytes binding in the placenta. VAR2CSA is most likely the parasite-encoded protein which mediates binding to the placental receptor CSA. Several domains have been shown to bind CSA in vitro; and it is apparent that a VAR2CSA-based vaccine cannot accommodate all the CSA binding domains and serovariants. It is thus of high priority to define minimal ligand binding regions throughout the VAR2CSA molecule. Methods: To define minimal CSA-binding regions/peptides of VAR2CSA, a phage display library based on the entire var2csa coding region was constructed. This library was screened on immobilized CSA and cells expressing CSA resulting in a limited number of CSA-binding phages. Antibodies against these peptides were affinity purified and tested for reactivity against CSA-binding infected erythrocytes. Results: The most frequently identified phages expressed peptides residing in the parts of VAR2CSA previously defined as CSA binding. In addition, most of the binding regions mapped to surface-exposed parts of VAR2CSA. The binding of a DBL2X peptide to CSA was confirmed with a synthetic peptide. Antibodies against a CSA-binding DBL2X peptide reacted with the surface of infected erythrocytes indicating that this epitope is accessible for antibodies on native VAR2CSA on infected erythrocytes. Conclusion: Short continuous regions of VAR2CSA with affinity for multiple types of CSA were defined. A number of these regions localize to CSA-binding domains and to surface-exposed regions within these domains and a synthetic peptide corresponding to a peptide sequence in DBL2 was shown to bind to CSA and not to CSC. It is likely that some of these epitopes are involved in native parasite CSA adhesion. However, antibodies directed against single epitopes did not inhibit parasite adhesion. This study supports phage display as a technique to identify CSA-binding regions of large proteins such as VAR2CSA.

    U2 - 10.1186/1475-2875-7-104

    DO - 10.1186/1475-2875-7-104

    M3 - Journal article

    C2 - 18534039

    VL - 7

    JO - Malaria Journal

    JF - Malaria Journal

    SN - 1475-2875

    IS - 104

    ER -