Comparison of allele frequencies of Plasmodium falciparum merozoite antigens in malaria infections sampled in different years in a Kenyan populationReport as inadecuate




Comparison of allele frequencies of Plasmodium falciparum merozoite antigens in malaria infections sampled in different years in a Kenyan population - Download this document for free, or read online. Document in PDF available to download.

Malaria Journal

, 15:261

First Online: 06 May 2016Received: 28 January 2016Accepted: 20 April 2016DOI: 10.1186-s12936-016-1304-8

Cite this article as: Ochola-Oyier, L.I., Okombo, J., Wagatua, N. et al. Malar J 2016 15: 261. doi:10.1186-s12936-016-1304-8

Abstract

BackgroundPlasmodium falciparum merozoite antigens elicit antibody responses in malaria-endemic populations, some of which are clinically protective, which is one of the reasons why merozoite antigens are the focus of malaria vaccine development efforts. Polymorphisms in several merozoite antigen-encoding genes are thought to arise as a result of selection by the human immune system.

MethodsThe allele frequency distribution of 15 merozoite antigens over a two-year period, 2007 and 2008, was examined in parasites obtained from children with uncomplicated malaria. In the same population, allele frequency changes pre- and post-anti-malarial treatment were also examined. Any gene which showed a significant shift in allele frequencies was also assessed longitudinally in asymptomatic and complicated malaria infections.

ResultsFluctuating allele frequencies were identified in codons 147 and 148 of reticulocyte-binding homologue Rh 5, with a shift from HD to YH haplotypes over the two-year period in uncomplicated malaria infections. However, in both the asymptomatic and complicated malaria infections YH was the dominant and stable haplotype over the two-year and ten-year periods, respectively. A logistic regression analysis of all three malaria infection populations between 2007 and 2009 revealed, that the chance of being infected with the HD haplotype decreased with time from 2007 to 2009 and increased in the uncomplicated and asymptomatic infections.

ConclusionRh5 codons 147 and 148 showed heterogeneity at both an individual and population level and may be under some degree of immune selection.

KeywordsRh5 Merozoite Plasmodium Malaria Electronic supplementary materialThe online version of this article doi:10.1186-s12936-016-1304-8 contains supplementary material, which is available to authorized users.

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Author: Lynette Isabella Ochola-Oyier - John Okombo - Njoroge Wagatua - Jacob Ochieng - Kevin K. Tetteh - Greg Fegan - Philip Bej

Source: https://link.springer.com/



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