title: Common surface-antigen var genes of limited diversity expressed by Plasmodium falciparum placental isolates separated by time and space.
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.
authors.affiliation: Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany.
authors.forename: Ayman
authors.initials: A
authors.lastname: Khattab
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kremsner
authors.forename: Mo-Quen
authors.initials: MQ
authors.lastname: Klinkert
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000235:genetics*; D002163:Cameroon; D005260:Female; D005681:Gabon; D005786:Gene Expression Regulation; D017125:Genes, Protozoan / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D010920:Placenta / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000235:genetics* / Q000302:isolation & purification; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000469:parasitology*; D013997:Time Factors
chemical_list: D000954:Antigens, Surface