Antibodies to variant surface antigens of Plasmodium falciparum-infected erythrocytes and adhesion inhibitory antibodies are associated with placental malaria and have overlapping and distinct targets.
We measured antibodies to chondroitin sulfate A (CSA)-binding and placental Plasmodium falciparum-infected red blood cells (PRBCs) among pregnant women with or without placental malaria. Immunoglobulin G to PRBC surface antigens was rare in uninfected primigravidae (3.7%), more prevalent in infected primigravidae (70%; P<.001), and common in infected (77%) and uninfected (83%) multigravidae. Similar patterns were seen for agglutinating antibodies, and antibodies were similar among women with past or active placental infection. PRBC adhesion to CSA was inhibited 60% by serum from infected primigravidae but 24% by serum from uninfected primigravidae (P=.025), whereas infection did not alter adhesion inhibition by multigravidae (77% inhibition)[corrected]. There was substantial heterogeneity in antibody type and levels. Antibodies did not correlate with parasite density or pregnancy outcome. Comparisons between antibodies suggest that adhesion-inhibitory antibodies and those to PRBC variant antigens have distinct and overlapping epitopes, may be acquired independently, and have different roles in immunity.
Beeson
James G
JG
Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Victoria, Australia. beeson@unimelb.edu.au
Mann
Emily J
EJ
Elliott
Salenna R
SR
Lema
Valentino M
VM
Tadesse
Eyob
E
Molyneux
Malcolm E
ME
Brown
Graham V
GV
Rogerson
Stephen J
SJ
D000328:Adult; D000373:Agglutinins / Q000032:analysis; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D002448:Cell Adhesion / Q000276:immunology; D002809:Chondroitin Sulfates / Q000378:metabolism; D004912:Erythrocytes / Q000276:immunology / Q000378:metabolism / Q000469:parasitology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D016778:Malaria, Falciparum / Q000097:blood / Q000276:immunology*; D008297:Male; D010922:Placenta Diseases / Q000276:immunology* / Q000469:parasitology; D010963:Plasmodium falciparum / Q000276:immunology*; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000097:blood / Q000276:immunology*; D011264:Pregnancy Trimesters / Q000276:immunology
D000373:Agglutinins; D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D002809:Chondroitin Sulfates