A VSG expression site-associated gene confers resistance to human serum in Trypanosoma rhodesiense

Cell. 1998 Dec 11;95(6):839-46. doi: 10.1016/s0092-8674(00)81706-7.


Infectivity of Trypanosoma brucei rhodesiense to humans is due to its resistance to a lytic factor present in human serum. In the ETat 1 strain this character was associated with antigenic variation, since expression of the ETat 1.10 variant surface glycoprotein was required to generate resistant (R) clones. In addition, in this strain transcription of a gene termed SRA was detected in R clones only. We show that the ETat 1.10 expression site is the one selectively transcribed in R variants. This expression site contains SRA as an expression site-associated gene (ESAG) and is characterized by the deletion of several ESAGs. Transfection of SRA into T.b. brucei was sufficient to confer resistance to human serum, identifying this gene as one of those responsible for T.b. rhodesiense adaptation to humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigenic Variation
  • Base Sequence
  • Blood
  • DNA, Protozoan
  • Gene Expression
  • Genes, Protozoan*
  • Humans
  • Molecular Sequence Data
  • Transcription, Genetic
  • Trypanosoma brucei rhodesiense / genetics*
  • Trypanosoma brucei rhodesiense / immunology
  • Trypanosoma brucei rhodesiense / pathogenicity*
  • Variant Surface Glycoproteins, Trypanosoma / genetics*


  • DNA, Protozoan
  • Variant Surface Glycoproteins, Trypanosoma

Associated data

  • GENBANK/AJ010094