TY - JOUR

T1 - Full-length recombinant Plasmodium falciparum VAR2CSA binds specifically to CSPG and induces potent parasite adhesion blocking antibodies

AU - Khunrae, Pongsak

AU - Dahlbäck, Madeleine

AU - Nielsen, Morten A

AU - Andersen, Gorm

AU - Ditlev, Sisse B

AU - Resende, Mafalda

AU - Pinto, Vera V

AU - Theander, Thor G

AU - Higgins, Matthew K

AU - Salanti, Ali

N1 - Copyright © 2010 Elsevier Inc. All rights reserved.

PY - 2010

Y1 - 2010

N2 - Plasmodium falciparum malaria remains one of the world's leading causes of human suffering and poverty. Each year, the disease takes 1-3 million lives, mainly in sub-Saharan Africa. The adhesion of parasite-infected erythrocytes to the vascular endothelium or the placenta is the key event in the pathogenesis of severe P. falciparum infection. In pregnant women the parasites express a single and unique member of the PfEMP1 family named VAR2CSA, which is associated with the ability of the infected erythrocytes to adhere specifically to chondroitin sulphate A (CSA) in the placenta. Several DBL domains from VAR2CSA molecules have been shown in vitro to bind to CSA, but it has also been demonstrated that DBL domains from other PfEMP1 proteins than VAR2CSA can bind CSA. In addition, the specificity of binding of VAR2CSA domains to glycosaminoglycans does not match that of VAR2CSA-expressing infected erythrocytes. This has led to speculation that the domains of native VAR2CSA need to come together to form a specific binding site, or that VAR2CSA might bind to CSA through a bridging molecule. Here, we describe the expression and purification of the complete extracellular region of VAR2CSA secreted at high yields from insect cells. Using surface plasmon resonance we demonstrate that VAR2CSA alone binds with nano-molar affinity to placental chondroitin sulphate proteoglycan (CSPG-h) and with significantly weaker affinity to other glycosaminoglycans, showing a similar specificity to that observed for infected erythrocytes. Antibodies raised against full-length VAR2CSA completely inhibit recombinant VAR2CSA binding as well as parasite binding to CSPG. This is the first study describing the successful production and functionality of a full-length PfEMP1. The specificity of the binding and anti-adhesion potency of induced IgG, together with the high yield production encourages the use of full-length PfEMP1 in vaccine development strategies.

AB - Plasmodium falciparum malaria remains one of the world's leading causes of human suffering and poverty. Each year, the disease takes 1-3 million lives, mainly in sub-Saharan Africa. The adhesion of parasite-infected erythrocytes to the vascular endothelium or the placenta is the key event in the pathogenesis of severe P. falciparum infection. In pregnant women the parasites express a single and unique member of the PfEMP1 family named VAR2CSA, which is associated with the ability of the infected erythrocytes to adhere specifically to chondroitin sulphate A (CSA) in the placenta. Several DBL domains from VAR2CSA molecules have been shown in vitro to bind to CSA, but it has also been demonstrated that DBL domains from other PfEMP1 proteins than VAR2CSA can bind CSA. In addition, the specificity of binding of VAR2CSA domains to glycosaminoglycans does not match that of VAR2CSA-expressing infected erythrocytes. This has led to speculation that the domains of native VAR2CSA need to come together to form a specific binding site, or that VAR2CSA might bind to CSA through a bridging molecule. Here, we describe the expression and purification of the complete extracellular region of VAR2CSA secreted at high yields from insect cells. Using surface plasmon resonance we demonstrate that VAR2CSA alone binds with nano-molar affinity to placental chondroitin sulphate proteoglycan (CSPG-h) and with significantly weaker affinity to other glycosaminoglycans, showing a similar specificity to that observed for infected erythrocytes. Antibodies raised against full-length VAR2CSA completely inhibit recombinant VAR2CSA binding as well as parasite binding to CSPG. This is the first study describing the successful production and functionality of a full-length PfEMP1. The specificity of the binding and anti-adhesion potency of induced IgG, together with the high yield production encourages the use of full-length PfEMP1 in vaccine development strategies.

U2 - 10.1016/j.jmb.2010.01.040

DO - 10.1016/j.jmb.2010.01.040

M3 - Journal article

C2 - 20109466

VL - 397

SP - 826

EP - 834

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

ER -