TY - JOUR
T1 - Human pregnancy-associated malaria-specific B cells target polymorphic, conformational epitopes in VAR2CSA
AU - Barfod, Lea
AU - Bernasconi, Nadia L
AU - Dahlbäck, Madeleine
AU - Jarrossay, David
AU - Andersen, Pernille Haste
AU - Salanti, Ali
AU - Ofori, Michael F
AU - Turner, Louise
AU - Resende, Mafalda
AU - Nielsen, Morten A
AU - Theander, Thor G
AU - Sallusto, Federica
AU - Lanzavecchia, Antonio
AU - Hviid, Lars
N1 - Keywords: Amino Acid Sequence; Animals; Antibodies, Monoclonal; Antigens, Protozoan; B-Lymphocytes; Blotting, Western; Cells, Cultured; Enzyme-Linked Immunosorbent Assay; Epitope Mapping; Epitopes, B-Lymphocyte; Female; Flow Cytometry; Humans; Jurkat Cells; Malaria, Falciparum; Microscopy, Fluorescence; Models, Molecular; Molecular Sequence Data; Plasmodium falciparum; Pregnancy; Pregnancy Complications, Parasitic; Sequence Alignment
PY - 2007
Y1 - 2007
N2 - Pregnancy-associated malaria (PAM) is caused by Plasmodium falciparum-infected erythrocytes (IEs) that bind to chondroitin sulphate A (CSA) in the placenta by PAM-associated clonally variant surface antigens (VSA). Pregnancy-specific VSA (VSA(PAM)), which include the PfEMP1 variant VAR2CSA, are targets of IgG-mediated protective immunity to PAM. Here, we report an investigation of the specificity of naturally acquired immunity to PAM, using eight human monoclonal IgG1 antibodies that react exclusively with intact CSA-adhering IEs expressing VSA(PAM). Four reacted in Western blotting with high-molecular-weight (> 200 kDa) proteins, while seven reacted with either the DBL3-X or the DBL5-epsilon domains of VAR2CSA expressed either as Baculovirus constructs or on the surface of transfected Jurkat cells. We used a panel of recombinant antigens representing DBL3-X domains from P. falciparum field isolates to evaluate B-cell epitope diversity among parasite isolates, and identified the binding site of one monoclonal antibody using a chimeric DBL3-X construct. Our findings show that there is a high-frequency memory response to VSA(PAM), indicating that VAR2CSA is a primary target of naturally acquired PAM-specific protective immunity, and demonstrate the value of human monoclonal antibodies and conformationally intact recombinant antigens in VSA characterization.
AB - Pregnancy-associated malaria (PAM) is caused by Plasmodium falciparum-infected erythrocytes (IEs) that bind to chondroitin sulphate A (CSA) in the placenta by PAM-associated clonally variant surface antigens (VSA). Pregnancy-specific VSA (VSA(PAM)), which include the PfEMP1 variant VAR2CSA, are targets of IgG-mediated protective immunity to PAM. Here, we report an investigation of the specificity of naturally acquired immunity to PAM, using eight human monoclonal IgG1 antibodies that react exclusively with intact CSA-adhering IEs expressing VSA(PAM). Four reacted in Western blotting with high-molecular-weight (> 200 kDa) proteins, while seven reacted with either the DBL3-X or the DBL5-epsilon domains of VAR2CSA expressed either as Baculovirus constructs or on the surface of transfected Jurkat cells. We used a panel of recombinant antigens representing DBL3-X domains from P. falciparum field isolates to evaluate B-cell epitope diversity among parasite isolates, and identified the binding site of one monoclonal antibody using a chimeric DBL3-X construct. Our findings show that there is a high-frequency memory response to VSA(PAM), indicating that VAR2CSA is a primary target of naturally acquired PAM-specific protective immunity, and demonstrate the value of human monoclonal antibodies and conformationally intact recombinant antigens in VSA characterization.
U2 - 10.1111/j.1365-2958.2006.05503.x
DO - 10.1111/j.1365-2958.2006.05503.x
M3 - Journal article
C2 - 17176260
SN - 0950-382X
VL - 63
SP - 335
EP - 347
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 2
ER -
