title: A large gene family for putative variant antigens shared by human and rodent malaria parasites.
abstract: A major mechanism whereby malaria parasites evade the host immune response to give chronic infections in patients' blood for months, or even years, is antigenic variation. In order to generate variant antigens, parasites require large multigene families. Although several gene families involved in these phenomena have been identified in the human malaria Plasmodium falciparum, to date no variant antigen gene families have been identified in malaria species that will infect widely used rodent laboratory hosts. Here we present, for the first time, to our knowledge, a large multigene family conserved in both rodent and human malarias, which is a strong candidate as a major variant antigen gene family. In each of four species of Plasmodium, three rodent malarias and the human pathogen P. vivax, homologues of the gene family were found to have a conserved three-exon structure. In the rodent malaria P. chabaudi, transcription of members of the gene family was developmentally regulated with maximum expression in late trophozoite stages, which is the developmental stage known to express variant antigen proteins.
authors.affiliation: Division of Infection and Immunity, IBLS, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Christoph S
authors.initials: CS
authors.lastname: Janssen
authors.forename: Michael P
authors.initials: MP
authors.lastname: Barrett
authors.forename: C Michael R
authors.initials: CM
authors.lastname: Turner
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Phillips
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis / Q000235:genetics*; D017124:Conserved Sequence / Q000235:genetics; D005091:Exons / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D017125:Genes, Protozoan / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008288:Malaria / Q000469:parasitology*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010802:Phylogeny; D010961:Plasmodium / Q000145:classification / Q000235:genetics*; D012376:Rodent Diseases / Q000469:parasitology*; D012377:Rodentia / Q000469:parasitology; D016415:Sequence Alignment
chemical_list: D000953:Antigens, Protozoan