Antigenic variation in malaria: a 3' genomic alteration associated with the expression of a P. knowlesi variant antigen

Mol Cell. 1999 Feb;3(2):131-41. doi: 10.1016/s1097-2765(00)80304-4.

Abstract

Antigenic variation of malaria parasites was discovered in P. knowlesi, using a schizont-infected cell agglutination (SICA) assay to detect variant antigens expressed at the surface of infected erythrocytes. Later studies utilizing stable clones, Pk1(A+) and its direct derivative, Pk1(B+)1+, showed that SICA[+] clones express distinct parasite-encoded antigens of approximately 200 kDa. Here we identify a P. knowlesi variant antigen gene and cDNA and demonstrate that it encodes the 205 kDa variant antigen expressed by B+ parasites. This gene belongs to a multigene family, which we term SICAvar. Its ten-exon structure with seven cysteine-rich coding modules is unique compared to P. falciparum var genes. Further, we highlight a 3' genomic alteration that we predict is related to SICAvar gene switching.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigenic Variation / genetics*
  • Antigens, Surface / genetics*
  • Antigens, Surface / immunology
  • Clone Cells
  • DNA, Complementary / genetics
  • Gene Expression Regulation
  • Genes, Protozoan*
  • Genes, Switch
  • Molecular Sequence Data
  • Multigene Family
  • Plasmodium knowlesi / genetics*
  • Plasmodium knowlesi / immunology
  • Protein Conformation
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics*
  • Protozoan Proteins / immunology
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / immunology
  • Sequence Alignment
  • Sequence Homology, Amino Acid

Substances

  • Antigens, Surface
  • DNA, Complementary
  • Protozoan Proteins
  • Recombinant Fusion Proteins

Associated data

  • GENBANK/AF078128
  • GENBANK/AF078129
  • GENBANK/AF078130