Mosquito Passage Dramatically Changes var Gene Expression in Controlled Human Plasmodium falciparum Infections

• Published in: PLoS pathogens Vol. 12; no. 4; p. e1005538
• Main Authors: Bachmann, Anna, Petter, Michaela, Krumkamp, Ralf, Esen, Meral, Held, Jana, Scholz, Judith A M, Li, Tao, Sim, B Kim Lee, Hoffman, Stephen L, Kremsner, Peter G, Mordmüller, Benjamin, Duffy, Michael F, Tannich, Egbert
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.04.2016; Public Library of Science (PLoS)
• Subjects: Animals; Antigenic Variation - genetics; Antigenic Variation - immunology; Antigens; Biology and Life Sciences; Chromosomes; Clinical trials; Culicidae; Deoxyribonucleic acid; DNA; Erythrocytes; Funding; Gene expression; Gene Expression - genetics; Genetic aspects; Genetic variation; Health aspects; Humans; Identification and classification; Infections; Malaria; Malaria, Falciparum - parasitology; Malaria, Falciparum - transmission; Medicine and Health Sciences; Mosquitoes; Open access; Parasites; Parasitic diseases; Plasmodium falciparum; Plasmodium falciparum - genetics; Proteins; Protozoan Proteins - genetics; RNA, Messenger - genetics; Volunteers
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1005538

Virulence of the most deadly malaria parasite Plasmodium falciparum is linked to the variant surface antigen PfEMP1, which is encoded by about 60 var genes per parasite genome. Although the expression of particular variants has been associated with different clinical outcomes, little is known about var gene expression at the onset of infection. By analyzing controlled human malaria infections via quantitative real-time PCR, we show that parasite populations from 18 volunteers expressed virtually identical transcript patterns that were dominated by the subtelomeric var gene group B and, to a lesser extent, group A. Furthermore, major changes in composition and frequency of var gene transcripts were detected between the parental parasite culture that was used to infect mosquitoes and Plasmodia recovered from infected volunteers, suggesting that P. falciparum resets its var gene expression during mosquito passage and starts with the broad expression of a specific subset of var genes when entering the human blood phase.