title: Use of Plasmodium falciparum culture-adapted field isolates for in vitro exflagellation-blocking assay.
abstract: BACKGROUND
  A major requirement for malaria elimination is the development of transmission-blocking interventions. In vitro transmission-blocking bioassays currently mostly rely on the use of very few Plasmodium falciparum reference laboratory strains isolated decades ago. To fill a piece of the gap between laboratory experimental models and natural systems, the purpose of this work was to determine if culture-adapted field isolates of P. falciparum are suitable for in vitro transmission-blocking bioassays targeting functional maturity of male gametocytes: exflagellation.
  
  
  METHODS
  Plasmodium falciparum isolates were adapted to in vitro culture before being used for in vitro gametocyte production. Maturation was assessed by microscopic observation of gametocyte morphology over time of culture and the functional viability of male gametocytes was assessed by microscopic counting of exflagellating gametocytes. Suitability for in vitro exflagellation-blocking bioassays was determined using dihydroartemisinin and methylene blue.
  
  
  RESULTS
  In vitro gametocyte production was achieved using two isolates from French Guiana and two isolates from Cambodia. Functional maturity of male gametocytes was assessed by exflagellation observations and all four isolates could be used in exflagellation-blocking bioassays with adequate response to methylene blue and dihydroartemisinin.
  
  
  CONCLUSIONS
  This work shows that in vitro culture-adapted P. falciparum field isolates of different genetic background, from South America and Southeast Asia, can successfully be used for bioassays targeting the male gametocyte to gamete transition, exflagellation.
authors.affiliation: Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. louisjerome973@hotmail.fr.|Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France. louisjerome973@hotmail.fr.
authors.forename: Louis-Jérôme
authors.initials: LJ
authors.lastname: Leba
authors.affiliation: Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. lmusset@pasteur-cayenne.fr.
authors.forename: Lise
authors.initials: L
authors.lastname: Musset
authors.affiliation: Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. spelleau@pasteur-cayenne.fr.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pelleau
authors.affiliation: Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France. yannick.estevez@ecofog.gf.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Estevez
authors.affiliation: Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France. carolinebirer@yahoo.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Birer
authors.affiliation: Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. sbriolant@pasteur-cayenne.fr.|Direction Interarmées du Service de Santé en Guyane, Cayenne, French Guiana, France. sbriolant@pasteur-cayenne.fr.|Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France. sbriolant@pasteur-cayenne.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Briolant
authors.affiliation: Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia. bwitkowski@pasteur-kh.org.
authors.forename: Benoit
authors.initials: B
authors.lastname: Witkowski
authors.affiliation: Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia. dmenard@pasteur-kh.org.
authors.forename: Didier
authors.initials: D
authors.lastname: Ménard
authors.affiliation: Department of Life Sciences, Imperial College, London, UK. michael.delves@imperial.ac.uk.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Delves
authors.affiliation: Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. eric.legrand@pasteur.fr.
authors.forename: Eric
authors.initials: E
authors.lastname: Legrand
authors.affiliation: Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France. christophe.duplais@ecofog.gf.
authors.forename: Christophe
authors.initials: C
authors.lastname: Duplais
authors.affiliation: Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. jean.o.popovici@gmail.com.|Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia. jean.o.popovici@gmail.com.
authors.forename: Jean
authors.initials: J
authors.lastname: Popovici
mesh_terms: D016778:Malaria, Falciparum / Q000469:parasitology / Q000517:prevention & control*; D010274:Parasitology / Q000379:methods*; D010963:Plasmodium falciparum / Q000302:isolation & purification / Q000502:physiology*; D012098:Reproduction