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This article is part of the supplement: Challenges in malaria research

Open Access Poster presentation

The repertoire diversity of the Plasmodium falciparum stevor multigene family in complicated and uncomplicated malaria in India

Surendra K Prajapati1*, Dolie D Laishram1, Sanjib Mohanty2, Jane M Carlton3 and Om P Singh1

  • * Corresponding author: Surendra K Prajapati

Author Affiliations

1 Molecular Biology Division, National Institute of Malaria Research, New Delhi 110077, lndia

2 Ispat General Hospital, Rourkela, Odisha 769011, India

3 Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA

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Malaria Journal 2012, 11(Suppl 1):P125  doi:10.1186/1475-2875-11-S1-P125


The electronic version of this article is the complete one and can be found online at: http://www.malariajournal.com/content/11/S1/P125


Published:15 October 2012

© 2012 Praiapati et al; licensee BioMed Central Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background

The deep vascular sequestration of parasitized erythrocytes is a central pathological event in falciparum malaria. Variant surface antigens are encoded mainly by three multi-copy gene families, namely, var, stevor, and rifín. Var is one of the most important families that plays a crucial role in antigenic variation and immune evasion. Clinical and epidemiological studies have shown that severe or complicated malaria is manifested in a limited number of patients. This indicates that a subset of these multigene families could be determinants in the manifestation of different malaria phenotypes. Recent studies have indicated the possible role of stevor (sub-telomeric variable open read), a multi-gene family, in erythrocyte invasion, antigenic variation and host cell modification, of infected erythrocytes. In this study, we describe the repertoire and diversity of members of the stevor multigene family in patients with complicated and uncomplicated malaria in India.

Materials and methods

Plasmodium falciparum complicated isolates (n=8) from Odisha and uncomplicated isolates (n=7) from Assam, Madhya Pradesh and Goa were collected. Members of the stevor multigene family were amplified using degenerate PCR primers. Amplified PCR products were cloned and a total of 35 clones per cloning experiment were sequenced. A maximum likelihood phylogeny was constructed in order to understand the genetic repertoire of members of the stevor multigene family in severe and non-severe isolates and extent of stevor repertoire in Indian isolates.

Results

A range of 21-31 unique sequences was obtained out of 35 clones sequenced for each of the 15 isolates. Nucleotide diversity analysis shows extensive genetic polymorphism that supports the hyper-variability nature of stevor multigene family in field isolates. The repertoire and diversity of the stevor multigene family varied between all four geographical regions of the Indian subcontinent. Phylogenetic tree analysis showed clustering of sequences from complicated isolates, and suggests that the stevor genetic repertoire is less diverse in comparison to uncomplicated isolates.

Conclusions

This study suggests an extensive genetic diversity of stevor in Indian P. falciparum isolates, however the genetic repertoire from complicated cases was less diverse. The high degree of stevor diversity has important implications for the design of effective anti-malaria control measures.

Acknowledgements

This work was supported by the ICMR-Centenary Postdoctoral Fellowship program of the Indian Council of Medical Research, New Delhi, India and in part by grant number D43TW007884 from the Fogarty International Center (FIC), US National Institutes of Health (NIH). The content is solely the responsibility of the authors and does not necessarily represent the views of the FIC or NIH.