Antibodies that inhibit binding of Plasmodium falciparum-infected erythrocytes to chondroitin sulfate A and to the C terminus of merozoite surface protein 1 correlate with reduced placental malaria in Cameroonian women

Infect Immun. 2004 Mar;72(3):1603-7. doi: 10.1128/IAI.72.3.1603-1607.2004.

Abstract

Plasmodium falciparum-infected erythrocytes often sequester in the placenta of pregnant women, producing placental malaria, a condition that can compromise the health of the developing fetus. Scientists are hopeful that a vaccine can be developed to prevent this condition. Immunological mechanisms responsible for eliminating parasites from the placenta remain unclear, but antibodies to the carboxyl-terminal 19-kDa segment of the merozoite surface protein 1 (MSP1-19), the ring-infected erythrocyte surface antigen (RESA), and an erythrocyte-surface ligand that binds chondroitin sulfate A (CSA-L) have been implicated. In addition, antibodies to sporozoite and liver-stage antigens could reduce initial parasite burdens. This study sought to determine if antibodies to the circumsporozoite protein (CSP), liver-stage antigen 1 (LSA1), RESA, MSP1-19, or CSA-L correlated with either the absence of placental parasites or low placental parasitemias. Using a frequency-matched case-control study design, we compared antibody levels in women (gravidity 1 to 11) with and without placental malaria. Results showed that women who were antibody negative for MSP1-19 were at a higher risk of having placental malaria than women with antibodies (P < 0.007). Furthermore, an association between high levels of antibodies that blocked the binding of infected erythrocytes to CSA and low placental parasitemias was observed (P = 0.02). On the other hand, women with high antibody levels at term to CSP, LSA1, and RESA were more likely to have placental malaria than antibody-negative women. Since antibodies to MSP1-19 and CSA-L were associated with reduced placental malaria, both antigens show promise for inclusion in a vaccine for women of child-bearing age.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Animals
  • Antibodies, Protozoan / blood*
  • Cameroon
  • Case-Control Studies
  • Chondroitin Sulfates / metabolism
  • Erythrocytes / parasitology
  • Female
  • Humans
  • In Vitro Techniques
  • Malaria Vaccines / immunology
  • Malaria, Falciparum / complications*
  • Malaria, Falciparum / immunology*
  • Malaria, Falciparum / parasitology
  • Merozoite Surface Protein 1 / genetics
  • Merozoite Surface Protein 1 / metabolism
  • Molecular Sequence Data
  • Placenta / parasitology*
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / immunology*
  • Plasmodium falciparum / isolation & purification
  • Pregnancy
  • Pregnancy Complications, Parasitic / immunology*
  • Pregnancy Complications, Parasitic / parasitology

Substances

  • Antibodies, Protozoan
  • Malaria Vaccines
  • Merozoite Surface Protein 1
  • Chondroitin Sulfates