Plasmodium falciparum Variant Surface Antigen Expression Patterns during Malaria

PLoS Pathogens

Michael A Quail¹  Peter C Bull¹  Chris I Newbold¹  Moses M Kortok²  Neil Hall³  Sue Kyes³  Matthew Berriman⁴  Kevin Marsh⁴ 

[1] Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom;The Institute for Genomic Research, Rockville, Maryland, United States of America;Wellcome Trust Sanger Institute, Hinxton, United Kingdom;Wellcome Trust/Kenya Medical Research Institute Collaborative Programme, Kilifi, Kenya

关键词: Sequence motif analysis;    Sequence analysis;    Malarial parasites;    DNA sequence analysis;    Malaria;    Parasitic diseases;    Comparative sequence analysis;    Cysteine;   

DOI  :  10.1371/journal.ppat.0010026

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The variant surface antigens expressed on Plasmodium falciparum–infected erythrocytes are potentially important targets of immunity to malaria and are encoded, at least in part, by a family of var genes, about 60 of which are present within every parasite genome. Here we use semi-conserved regions within short var gene sequence “tags” to make direct comparisons of var gene expression in 12 clinical parasite isolates from Kenyan children. A total of 1,746 var clones were sequenced from genomic and cDNA and assigned to one of six sequence groups using specific sequence features. The results show the following. (1) The relative numbers of genomic clones falling in each of the sequence groups was similar between parasite isolates and corresponded well with the numbers of genes found in the genome of a single, fully sequenced parasite isolate. In contrast, the relative numbers of cDNA clones falling in each group varied considerably between isolates. (2) Expression of sequences belonging to a relatively conserved group was negatively associated with the repertoire of variant surface antigen antibodies carried by the infected child at the time of disease, whereas expression of sequences belonging to another group was associated with the parasite “rosetting” phenotype, a well established virulence determinant. Our results suggest that information on the state of the host–parasite relationship in vivo can be provided by measurements of the differential expression of different var groups, and need only be defined by short stretches of sequence data.

【 授权许可】

CC BY