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| Content Provider | World Health Organization (WHO)-Global Index Medicus |
|---|---|
| Author | Jackson, Andrew P. Van Tonder, Andries Marcello, Lucio Mcquillan, Jacqueline Brown, Robert Hertz-fowler, Christiane Allison, Harriet C. Burton, Peter Quail, Michael A. Ginger, Michael L. Gilderthorp, Ruth Berriman, Matthew Berry, Andrew Gamble, John Aslett, Martin Sanders, Mandy J. Vavrova-anderson, Jana Otto, Thomas D. Barry, J. David Field, Mark C. Browne, Hilary Corton, Nicola Hauser, Heidi |
| Description | Author Affiliation: Jackson AP ( Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom. andrew.jackson@sanger.ac.uk); |
| Abstract | Antigenic variation enables pathogens to avoid the host immune response by continual switching of surface proteins. The protozoan blood parasite Trypanosoma brucei causes human African trypanosomiasis ('sleeping sickness') across sub-Saharan Africa and is a model system for antigenic variation, surviving by periodically replacing a monolayer of variant surface glycoproteins (VSG) that covers its cell surface. We compared the genome of Trypanosoma brucei with two closely related parasites Trypanosoma congolense and Trypanosoma vivax, to reveal how the variant antigen repertoire has evolved and how it might affect contemporary antigenic diversity. We reconstruct VSG diversification showing that Trypanosoma congolense uses variant antigens derived from multiple ancestral VSG lineages, whereas in Trypanosoma brucei VSG have recent origins, and ancestral gene lineages have been repeatedly co-opted to novel functions. These historical differences are reflected in fundamental differences between species in the scale and mechanism of recombination. Using phylogenetic incompatibility as a metric for genetic exchange, we show that the frequency of recombination is comparable between Trypanosoma congolense and Trypanosoma brucei but is much lower in Trypanosoma vivax. Furthermore, in showing that the C-terminal domain of Trypanosoma brucei VSG plays a crucial role in facilitating exchange, we reveal substantial species differences in the mechanism of VSG diversification. Our results demonstrate how past VSG evolution indirectly determines the ability of contemporary parasites to generate novel variant antigens through recombination and suggest that the current model for antigenic variation in Trypanosoma brucei is only one means by which these parasites maintain chronic infections. |
| ISSN | 00278424 |
| e-ISSN | 10916490 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Issue Number | 9 |
| Volume Number | 109 |
| Language | English |
| Publisher | National Academy of Sciences |
| Publisher Date | 2012-02-01 |
| Publisher Place | United States |
| Access Restriction | Open |
| Subject Keyword | Antigenic Variation Genetics Evolution, Molecular Genome, Protozoan Immune Evasion Trypanosoma Brucei Brucei Immunology Trypanosoma Congolense Trypanosoma Vivax Variant Surface Glycoproteins, Trypanosoma Amino Acid Sequence Animals DNA, Protozoan Models, Molecular Molecular Sequence Data Phylogeny Protein Conformation Protozoan Proteins Chemistry Recombination, Genetic Sequence Alignment Sequence Homology, Amino Acid Species Specificity Comparative Study Research Support, Non-U.S. Gov't Video-Audio Media Multidisciplinary |
| Content Type | Text |
| Resource Type | Article |
| Subject | Multidisciplinary |
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