Poster Presentation Lorne Infection and Immunity 2014

Acquisition and maintenance of IgG responses to Plasmodium falciparum and P. vivax during pregnancy and post-partum (#176)

A McLean 1 2 , M Boel 3 , R McGready 3 4 5 , J A Simpson 2 , S J Viladpai-nguen 3 , M Avril 6 , J Smith 6 , D Narum 7 , R Anders 8 , T Tsuboi 9 , J G Beeson 1 , F Nosten 3 4 5 , F JI Fowkes 1 2 10
  1. Burnet Institute, Melbourne, VIC, Australia
  2. Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, University Of Melbourne, Melbourne, Aust
  3. Shoklo Malaria Research Unit, Mae Sot, Thailand
  4. Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
  5. Centre for Tropical Medicine UK, University of Oxford, Oxford, UK
  6. Seattle Biomedical Research Institute, Seattle, Washington, USA
  7. Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases/National Institutes of Health, Rockville, Maryland, USA
  8. Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia
  9. Malaria Research Unit, Cell-Free Science and Technology Research Centre, Ehime University, Ehime, Japan
  10. Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia

Pregnant women are more susceptible to, and more severely affected by, malaria and other infectious diseases. In malaria endemic regions pregnant women typically develop high parasite densities, placental infection and associated complications, despite substantial immunity to malaria that may have been acquired prior to pregnancy. This has largely been attributed to both the modulation of maternal immune responses and the sequestration of Plasmodium falciparum parasites in the placenta. Interestingly, previous data have indicated that post-partum women are more susceptible to P. vivax, yet protected against P. falciparum, compared to non-pregnant controls. However, there is limited data on the acquisition and maintenance of antibody responses in the post-partum period, and their relation to malaria species is unclear. Furthermore, there are limited data on malarial immunity among pregnant women in low transmission settings, in Asia, and in a setting where P. falciparum and P. vivax are prevalent. In a case-control study of post-partum women on the Thai-Burmese border, we measured IgG levels to P. falciparum merozoite antigens (AMA1, EBA-175, MSP2, MSP3, Rh2, schizont extract) and P. vivax merozoite antigens (Pv-AMA1, Pv-MSP1-10, Pv-DBP) and the P. falciparum pregnancy-specific antigen VAR2CSA-DBL5 by ELISA at 4-weekly intervals following pregnancy in 149 pregnancy cases and 149 non-pregnant controls (over 1400 samples in total). Longitudinal analyses revealed that at the individual level, antibody responses are dynamic both during gestation and post partum. Antibody responses to both P. falciparum and P. vivax merozoite responses were relatively short lived. The most dynamic species-specific responses were seen in women who experienced active infection. This study provides a comprehensive analysis of antibody dynamics towards two Plasmodium spp. and contributes to our understanding of maintenance of malaria antibodies both during and after pregnancy.