title: Expression of Plasmodium falciparum genes involved in erythrocyte invasion varies among isolates cultured directly from patients.
abstract: Plasmodium falciparum merozoites invade erythrocytes using a range of alternative ligands that includes erythrocyte binding antigenic proteins (EBAs) and reticulocyte binding protein homologues (Rh). Variation in the expression of some of these genes among culture-adapted parasite lines correlates with the use of different erythrocyte receptors. Here, expression profiles of four Rh genes and eba175 are analysed in a sample of 42 isolates cultured from malaria patients in Kenya. The profiles cluster into distinct groups, largely because of very strong negative correlations between the levels of expression of particular gene pairs (Rh1 versus Rh2b, eba175 versus Rh2b, and eba175 versus Rh4), previously associated with alternative invasion pathways in culture-adapted parasite lines. High levels of eba175 are seen in isolates in expression profile group I, and may be associated with sialic acid-dependent invasion. Groups II and III are, respectively, characterized by high levels of Rh2b and Rh4, and are more likely to be associated with sialic acid-independent invasion.
authors.affiliation: Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
authors.forename: Susana
authors.initials: S
authors.lastname: Nery
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Deans
authors.forename: Moses
authors.initials: M
authors.lastname: Mosobo
authors.forename: Kevin
authors.initials: K
authors.lastname: Marsh
authors.forename: J Alexandra
authors.initials: JA
authors.lastname: Rowe
authors.forename: David J
authors.initials: DJ
authors.lastname: Conway
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D001483:Base Sequence; D002648:Child; D016054:DNA, Protozoan / Q000235:genetics; D004912:Erythrocytes / Q000469:parasitology*; D018628:Gene Dosage; D020869:Gene Expression Profiling; D017125:Genes, Protozoan; D006801:Humans; D066298:In Vitro Techniques; D016778:Malaria, Falciparum / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D015800:Protozoan Proteins / Q000235:genetics; D014774:Virulence / Q000235:genetics
chemical_list: D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D015800:Protozoan Proteins; C065668:erythrocyte-binding antigen 175, Plasmodium