title: New insights into acquisition, boosting, and longevity of immunity to malaria in pregnant women.
abstract: BACKGROUND
  How antimalarial antibodies are acquired and maintained during pregnancy and boosted after reinfection with Plasmodium falciparum and Plasmodium vivax is unknown.
  
  
  METHODS
  A nested case-control study of 467 pregnant women (136 Plasmodium-infected cases and 331 uninfected control subjects) in northwestern Thailand was conducted. Antibody levels to P. falciparum and P. vivax merozoite antigens and the pregnancy-specific PfVAR2CSA antigen were determined at enrollment (median 10 weeks gestation) and throughout pregnancy until delivery.
  
  
  RESULTS
  Antibodies to P. falciparum and P. vivax were highly variable over time, and maintenance of high levels of antimalarial antibodies involved highly dynamic responses resulting from intermittent exposure to infection. There was evidence of boosting with each successive infection for P. falciparum responses, suggesting the presence of immunological memory. However, the half-lives of Plasmodium antibody responses were relatively short, compared with measles (457 years), and much shorter for merozoite responses (0.8-7.6 years), compared with PfVAR2CSA responses (36-157 years). The longer half-life of antibodies to PfVAR2CSA suggests that antibodies acquired in one pregnancy may be maintained to protect subsequent pregnancies.
  
  
  CONCLUSIONS
  These findings may have important practical implications for predicting the duration of vaccine-induced responses by candidate antigens and supports the development of malaria vaccines to protect pregnant women.
authors.affiliation: Macfarlane Burnet Institute of Medical Research, Melbourne, Australia. fowkes@burnet.edu.au
authors.forename: Freya J I
authors.initials: FJ
authors.lastname: Fowkes
authors.forename: Rose
authors.initials: R
authors.lastname: McGready
authors.forename: Nadia J
authors.initials: NJ
authors.lastname: Cross
authors.forename: Mirja
authors.initials: M
authors.lastname: Hommel
authors.forename: Julie A
authors.initials: JA
authors.lastname: Simpson
authors.forename: Salenna R
authors.initials: SR
authors.lastname: Elliott
authors.forename: Jack S
authors.initials: JS
authors.lastname: Richards
authors.forename: Kurt
authors.initials: K
authors.lastname: Lackovic
authors.forename: Jacher
authors.initials: J
authors.lastname: Viladpai-Nguen
authors.forename: David
authors.initials: D
authors.lastname: Narum
authors.forename: Takafumi
authors.initials: T
authors.lastname: Tsuboi
authors.forename: Robin F
authors.initials: RF
authors.lastname: Anders
authors.forename: François
authors.initials: F
authors.lastname: Nosten
authors.forename: James G
authors.initials: JG
authors.lastname: Beeson
mesh_terms: D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D000962:Antimalarials / Q000494:pharmacology; D016022:Case-Control Studies; D002738:Chloroquine / Q000494:pharmacology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D016778:Malaria, Falciparum / Q000150:complications / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D016780:Malaria, Vivax / Q000150:complications / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D010963:Plasmodium falciparum / Q000276:immunology*; D010966:Plasmodium vivax / Q000276:immunology*; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000097:blood / Q000276:immunology* / Q000517:prevention & control; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000962:Antimalarials; D007074:Immunoglobulin G; D002738:Chloroquine