Global selection of Plasmodium falciparum virulence antigen expression by host antibodies

Sci Rep. 2016 Jan 25:6:19882. doi: 10.1038/srep19882.

Abstract

Parasite proteins called PfEMP1 that are inserted on the surface of infected erythrocytes, play a key role in the severe pathology associated with infection by the Plasmodium falciparum malaria parasite. These proteins mediate binding of infected cells to the endothelial lining of blood vessels as a strategy to avoid clearance by the spleen and are major targets of naturally acquired immunity. PfEMP1 is encoded by a large multi-gene family called var. Mutually-exclusive transcriptional switching between var genes allows parasites to escape host antibodies. This study examined in detail the patterns of expression of var in a well-characterized sample of parasites from Kenyan Children. Instead of observing clear inverse relationships between the expression of broad sub-classes of PfEMP1, we found that expression of different PfEMP1 groups vary relatively independently. Parasite adaptation to host antibodies also appears to involve a general reduction in detectable var gene expression. We suggest that parasites switch both between different PfEMP1 variants and between high and low expression states. Such a strategy could provide a means of avoiding immunological detection and promoting survival under high levels of host immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies / immunology
  • Antigens, Protozoan / immunology*
  • Erythrocytes / chemistry
  • Erythrocytes / immunology
  • Erythrocytes / parasitology
  • Gene Expression / immunology
  • Host-Parasite Interactions / immunology
  • Humans
  • Kenya
  • Malaria, Falciparum / immunology*
  • Malaria, Falciparum / parasitology
  • Plasmodium falciparum / immunology*
  • Plasmodium falciparum / pathogenicity
  • Protozoan Proteins / chemistry*
  • Protozoan Proteins / immunology
  • Surface Properties

Substances

  • Antibodies
  • Antigens, Protozoan
  • Protozoan Proteins
  • erythrocyte membrane protein 1, Plasmodium falciparum