title: Falciparum malaria parasites invade erythrocytes that lack glycophorin A and B (MkMk). Strain differences indicate receptor heterogeneity and two pathways for invasion.
abstract: To determine the ligands on erythrocytes for invasion by Plasmodium falciparum, we tested invasion into MkMk erythrocytes that lack glycophorins A and B and enzyme-treated erythrocytes by parasites that differ in their requirement for erythrocyte sialic acid. The 7G8 strain invaded MkMk erythrocytes and neuraminidase-treated normal erythrocytes with greater than 50% the efficiency of normal erythrocytes. In contrast, the Camp strain invaded MkMk erythrocytes at 20% of control and neuraminidase-treated normal erythrocytes at only 1.8% of control. Invasion of MkMk erythrocytes by 7G8 parasites was unaffected by treatment with neuraminidase but was markedly reduced by treatment with trypsin. In contrast, invasion of MkMk cells by Camp parasites was markedly reduced by neuraminidase but was unaffected by trypsin. We conclude that the 7G8 and Camp strains differ in ligand requirements for invasion and that 7G8 requires a trypsin sensitive ligand distinct from glycophorins A and B.
authors.affiliation: Walter Reed Army Institute of Research, Washington, District of Columbia 20307-5100.
authors.forename: T J
authors.initials: TJ
authors.lastname: Hadley
authors.forename: F W
authors.initials: FW
authors.lastname: Klotz
authors.forename: G
authors.initials: G
authors.lastname: Pasvol
authors.forename: J D
authors.initials: JD
authors.lastname: Haynes
authors.forename: M H
authors.initials: MH
authors.lastname: McGinniss
authors.forename: Y
authors.initials: Y
authors.lastname: Okubo
authors.forename: L H
authors.initials: LH
authors.lastname: Miller
mesh_terms: D000818:Animals; D004912:Erythrocytes / Q000469:parasitology*; D005470:Fluorometry; D006021:Glycophorins / Q000032:analysis*; D006801:Humans; D008288:Malaria / Q000097:blood*; D009439:Neuraminidase / Q000378:metabolism; D010963:Plasmodium falciparum; D012795:Sialoglycoproteins / Q000032:analysis*; D013045:Species Specificity; D014357:Trypsin / Q000378:metabolism
chemical_list: D006021:Glycophorins; D012795:Sialoglycoproteins; D009439:Neuraminidase; D014357:Trypsin