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Day KP, Artzy-Randrup Y, Tiedje KE, Rougeron V, Chen DS, Rask TS, Rorick MM, Migot-Nabias F, Deloron P, Luty AJF, Pascual M. Evidence of strain structure in Plasmodium falciparum var gene repertoires in children from Gabon, West Africa. Proc Natl Acad Sci U S A 2017; 114:E4103-E4111. [PMID: 28461509 PMCID: PMC5441825 DOI: 10.1073/pnas.1613018114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Existing theory on competition for hosts between pathogen strains has proposed that immune selection can lead to the maintenance of strain structure consisting of discrete, weakly overlapping antigenic repertoires. This prediction of strain theory has conceptual overlap with fundamental ideas in ecology on niche partitioning and limiting similarity between coexisting species in an ecosystem, which oppose the hypothesis of neutral coexistence. For Plasmodium falciparum, strain theory has been specifically proposed in relation to the major surface antigen of the blood stage, known as PfEMP1 and encoded by the multicopy multigene family known as the var genes. Deep sampling of the DBLα domain of var genes in the local population of Bakoumba, West Africa, was completed to define whether patterns of repertoire overlap support a role of immune selection under the opposing force of high outcrossing, a characteristic of areas of intense malaria transmission. Using a 454 high-throughput sequencing protocol, we report extremely high diversity of the DBLα domain and a large parasite population with DBLα repertoires structured into nonrandom patterns of overlap. Such population structure, significant for the high diversity of var genes that compose it at a local level, supports the existence of "strains" characterized by distinct var gene repertoires. Nonneutral, frequency-dependent competition would be at play and could underlie these patterns. With a computational experiment that simulates an intervention similar to mass drug administration, we argue that the observed repertoire structure matters for the antigenic var diversity of the parasite population remaining after intervention.
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Affiliation(s)
- Karen P Day
- School of Biosciences, The University of Melbourne, Parkville, VIC 3052, Australia;
- Department of Microbiology, New York University, New York, NY 10016
| | - Yael Artzy-Randrup
- Theoretical Ecology Group, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109
| | - Kathryn E Tiedje
- School of Biosciences, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Microbiology, New York University, New York, NY 10016
| | - Virginie Rougeron
- Department of Microbiology, New York University, New York, NY 10016
- Laboratoire Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle, UMR 224-5290 CNRS, Institut de Recherche pour le Développement-Université de Montpellier, Centre Institut de Recherche pour le Développement de Montpellier, 34394 Montpellier, France
| | - Donald S Chen
- Department of Microbiology, New York University, New York, NY 10016
- Department of Medicine, New York Medical College, Valhalla, NY 10595
| | - Thomas S Rask
- School of Biosciences, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Microbiology, New York University, New York, NY 10016
| | - Mary M Rorick
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637
| | - Florence Migot-Nabias
- Institut de Recherche pour le Développement, UMR 216 Mère et Enfant Face aux Infections Tropicales, 75006 Paris, France
- Communautés d'Universités et Établissements, Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75006 Paris, France
| | - Philippe Deloron
- Institut de Recherche pour le Développement, UMR 216 Mère et Enfant Face aux Infections Tropicales, 75006 Paris, France
- Communautés d'Universités et Établissements, Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75006 Paris, France
| | - Adrian J F Luty
- Institut de Recherche pour le Développement, UMR 216 Mère et Enfant Face aux Infections Tropicales, 75006 Paris, France
- Communautés d'Universités et Établissements, Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75006 Paris, France
| | - Mercedes Pascual
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637
- Santa Fe Institute, Santa Fe, NM 87501
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