Use of Plasmodium falciparum culture-adapted field isolates for in vitro exflagellation-blocking assay.

Louis-Jérôme Leba (1, 2) , Lise Musset (1) , Stéphane Pelleau (1) , Yannick Estevez (2) , Caroline Birer (2) , Sébastien Briolant (1, 3, 4) , Benoit Witkowski (5) , Didier Ménard (5) , Michael J Delves (6) , Eric Legrand (1) , Christophe Duplais (2) , Jean Popovici (1, 5)

1 Laboratoire de Parasitologie [Cayenne, Guyane française]
2 UMR ECOFOG - Ecologie des forêts de Guyane
3 Direction Interarmées du Service de Santé en Guyane
4 IRBA - Institut de Recherche Biomédicale des Armées [Brétigny-sur-Orge]
5 Institut Pasteur du Cambodge
6 Department of Life Sciences

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. 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. 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. 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.

Domains: Parasitology

Louis-Jérôme Leba, Lise Musset, Stéphane Pelleau, Yannick Estevez, Caroline Birer, et al.. Use of Plasmodium falciparum culture-adapted field isolates for in vitro exflagellation-blocking assay.. Malaria Journal, 2015, 14, pp.234. ⟨10.1186/s12936-015-0752-x⟩. ⟨hal-01182753⟩