Common surface-antigen var genes of limited diversity expressed by Plasmodium falciparum placental isolates separated by time and space

J Infect Dis. 2003 Feb 1;187(3):477-83. doi: 10.1086/368266. Epub 2003 Jan 24.

Abstract

Plasmodium falciparum placental parasites from Cameroon have been shown to express surface variant var genes encoding Duffy binding-like (DBL)-gamma domains that bind chondroitin sulfate A. All 5 domains exhibited sequences with 39%-55% amino acid (aa) identities and appear sufficiently conserved to function in receptor binding. Transcripts of 2 samples showed complete conservation over 4 kb, demonstrating for the first time distinct conserved placental var genes. Four placental isolates from Gabon collected 4 years later expressed DBL-gamma sequences with 85%-99% aa identities to those from Cameroon, confirming the conserved nature of placental variants separated by time and location. Five peripheral parasites from children also displayed DBL-gamma sequences with 75%-97% homologies. From this, it can be concluded that P. falciparum parasites expressing unique var DBL-gamma genes can cause placental malaria, referred to as varPAM genes. This demonstration of structurally/functionally constrained DBL-gamma chondroitin sulfate A-binding domains is relevant to understanding pregnancy-associated malaria pathogenesis and to vaccine development.

Publication types

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

MeSH terms

  • Animals
  • Antigens, Surface / genetics*
  • Cameroon
  • Female
  • Gabon
  • Gene Expression Regulation*
  • Genes, Protozoan / genetics*
  • Genetic Variation / genetics*
  • Humans
  • Molecular Sequence Data
  • Phylogeny
  • Placenta / parasitology*
  • Plasmodium falciparum / genetics*
  • Plasmodium falciparum / isolation & purification
  • Pregnancy
  • Pregnancy Complications, Infectious / parasitology*
  • Time Factors

Substances

  • Antigens, Surface

Associated data

  • GENBANK/AF547098
  • GENBANK/AF547099
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