title: Plasmodium falciparum population dynamics in a cohort of pregnant women in Senegal.
abstract: BACKGROUND
  Pregnant women acquire protective antibodies that cross-react with geographically diverse placental Plasmodium falciparum isolates, suggesting that surface molecules expressed on infected erythrocytes by pregnancy-associated malaria (PAM) parasites have conserved epitopes and, that designing a PAM vaccine may be envisaged. VAR2CSA is the main candidate for a pregnancy malaria vaccine, but vaccine development may be complicated by its sequence polymorphism.
  
  
  METHODS
  The dynamics of P. falciparum genotypes during pregnancy in 32 women in relation to VAR2CSA polymorphism and immunity was determined. The polymorphism of the msp2 gene and five microsatellites was analysed in consecutive parasite isolates, and the DBL5epsilon + Interdomain 5 (Id5) part of the var2csa gene of the corresponding samples was cloned and sequenced to measure variation.
  
  
  RESULTS
  In primigravidae, the multiplicity of infection in the placenta was associated with occurrence of low birth weight babies. Some parasite genotypes were able to persist over several weeks and, still be present in the placenta at delivery particularly when the host anti-VAR2CSA antibody level was low. Comparison of diversity among genotyping markers confirmed that some PAM parasites may harbour more than one var2csa gene copy in their genome.
  
  
  CONCLUSIONS
  Host immunity to VAR2CSA influences the parasite dynamics during pregnancy, suggesting that the acquisition of protective immunity requires pre-exposure to a limited number of parasite variants. Presence of highly conserved residues in surface-exposed areas of the VAR2CSA immunodominant DBL5epsilon domain, suggest its potential in inducing antibodies with broad reactivity.
authors.affiliation: Institut de Recherche pour le Développement, Université Paris Descartes, France. julietteguitard@yahoo.fr
authors.forename: Juliette
authors.initials: J
authors.lastname: Guitard
authors.forename: Pernille
authors.initials: P
authors.lastname: Andersen
authors.forename: Caroline
authors.initials: C
authors.lastname: Ermont
authors.forename: Sédami
authors.initials: S
authors.lastname: Gnidehou
authors.forename: Nadine
authors.initials: N
authors.lastname: Fievet
authors.forename: Ole
authors.initials: O
authors.lastname: Lund
authors.forename: Philippe
authors.initials: P
authors.lastname: Deloron
authors.forename: Nicaise Tuikue
authors.initials: NT
authors.lastname: Ndam
mesh_terms: D000595:Amino Acid Sequence; D000953:Antigens, Protozoan / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015331:Cohort Studies; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016778:Malaria, Falciparum / Q000276:immunology* / Q000469:parasitology; D018895:Microsatellite Repeats / Q000235:genetics; D008969:Molecular Sequence Data; D010920:Placenta / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D011110:Polymorphism, Genetic / Q000235:genetics; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000097:blood / Q000235:genetics* / Q000276:immunology; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D012675:Senegal / Q000453:epidemiology
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C512601:VAR2CSA protein, Plasmodium falciparum; C065974:merozoite surface protein 2, Plasmodium