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PLoS One. 2013 Apr 12;8(4):e61323. doi: 10.1371/journal.pone.0061323. Print 2013.

Structure-function-immunogenicity studies of PfEMP1 domain DBL2βPF11_0521, a malaria parasite ligand for ICAM-1.

Author information

1
Seattle Biomedical Research Institute, Seattle, Washington, USA.

Abstract

Plasmodium falciparum virulence has been ascribed to its ability to sequester in deep vascular beds, mediated by the variant surface antigen family PfEMP1 binding endothelial receptors like ICAM-1. We previously observed that naturally-acquired antibodies that block a PfEMP1 domain, DBL2β of PF11_0521 allele, from binding to the human ICAM1 receptor, reduce the risk of malaria hospitalization in children. Here, we find that DBL2βPF11_0521 binds ICAM-1 in the low nM range and relate the structure of this domain with its function and immunogenicity. We demonstrate that the interaction with ICAM-1 is not impaired by point mutations in the N-terminal subdomain or in the flexible Loop 4 of DBL2βPF11_0521, although both substructures were previously implicated in binding ICAM-1. These data will help to refine the existing model of DBLβ::ICAM-1 interactions. Antibodies raised against full-length DBL2βPF11_0521, but not truncated forms lacking the N terminal fragment, block its interaction with ICAM-1. Our data suggest that full length domain is optimal for displaying functional epitopes and has a broad surface of interaction with ICAM-1 that is not disrupted by individual amino acid substitutions at putative key residues. This information might be important for the future design of anti-malarial vaccines based on PfEMP1 antigens.

PMID:
23593462
PMCID:
PMC3625211
DOI:
10.1371/journal.pone.0061323
[Indexed for MEDLINE]
Free PMC Article

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