Skip to main content

Is the single variant form of Plasmodium vivax Duffy binding protein-II (PvDBP-II) adequate for inclusion in a PvDBP-II-based vaccine?

The binding domain of Duffy protein (DBP-II) is a leading vaccine candidate of Plasmodium vivax. In order to develop a successful vivax malaria vaccine based on DBP-II, the antigenic diversity and also naturally occurring functional antibodies to different PvDBP-II variant types in the various populations must be known. To define whether the polymorphisms in PvDBP-II influenced the nature of functional antibody responses, this investigation was designed to evaluate naturally acquired antibodies to five circulating variant forms of DBP-II antigens in infected individuals with P. vivax living in hypoendemic areas in Iran. Sequence diversity of pvdbp-II gene was performed in 63 Iranian P. vivax isolates collected during 2008-2012. The sequencing analysis showed twenty two single nucleotide polymorphisms in PvDBP-II, resulting in 16 different haplotypes among the Iranian P. vivax isolates. Five of 16 genetically distinct variants were expressed in E. coli, and anti-DBP-II responses were measured in P. vivax-infected individuals (n = 202). Also, by performing immune-depletion ELISA experiments, antibody responses to the conserved sites of all five allelic forms were evaluated using the corresponding and non-corresponding patients’ sera (n = 20). ELISA results revealed that naturally acquired anti-PvDBP-II IgG were recognized all five expressed variant forms with no statistically difference (P > 0.05, Cochran’s Q test). The antibody depletion experiments also showed presence of the cross-reactive antibody responses to heterologous variants of PvDBP-II in Iranian individuals who were infected with distinct allelic forms of the PvDBP-II. Finally, all five examined variant forms of DBP-II were expressed transiently on the surface of COS-7 cells to determine whether people exposed to vivax malaria acquire antibodies that have the ability to block erythrocyte cytoadherence to PvDBP-II. The anti-DBP-II IgG block heterologous and homologous expressed DBP-II function, indicating that the protective immunity against PvDBP-II binding is not strain specific. In conclusion, the present results indicate that the single variant of PvDBP-II is adequate to be included in a PvDBP-II-based vaccine.

Author information

Authors and Affiliations

Authors

Rights and permissions

Open Access  This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

The Creative Commons Public Domain Dedication waiver (https://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Valizadeh, V., Zakeri, S., Mehrizi, A.A. et al. Is the single variant form of Plasmodium vivax Duffy binding protein-II (PvDBP-II) adequate for inclusion in a PvDBP-II-based vaccine?. Malar J 13, P95 (2014). https://doi.org/10.1186/1475-2875-13-S1-P95

Download citation

  • Published:

  • DOI: https://doi.org/10.1186/1475-2875-13-S1-P95

Keywords

  • Antibody Response
  • Variant Form
  • Vivax Malaria
  • Malaria Vaccine
  • Allelic Form