Antigenic variation of Ehrlichia chaffeensis resulting from differential expression of the 28-kilodalton protein gene family

Infect Immun. 2002 Apr;70(4):1824-31. doi: 10.1128/IAI.70.4.1824-1831.2002.

Abstract

The transcriptional activity and allele variation of the 28-kDa outer membrane protein gene (p28) of Ehrlichia chaffeensis were analyzed to determine the mechanism of the antigenic variation of the 28-kDa outer membrane proteins. Reverse transcriptase PCR amplification of mRNA indicated that 16 of the 22 members of the p28 multigene family were transcribed. Amino acid sequence analysis indicated that the p28-19 protein was produced in vitro in the Arkansas strain. The p28-19 gene and its promoter region were sequenced and compared in 12 clinical isolates of E. chaffeensis to determine allele variation. The variation of the p28-19 gene among the isolates is limited to three types represented by strains Arkansas, 91HE17, and Sapulpa, respectively. These results indicate that the majority of the p28 genes are active genes and that antigenic variation of the E. chaffeensis 28-kDa proteins may result from differential expression of the p28 gene family members rather than gene conversion.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Bacterial Outer Membrane Proteins / chemistry
  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Outer Membrane Proteins / immunology
  • Ehrlichia chaffeensis / genetics
  • Ehrlichia chaffeensis / immunology*
  • Genes, Bacterial*
  • Molecular Sequence Data
  • Multigene Family*
  • Promoter Regions, Genetic
  • Transcription, Genetic

Substances

  • Bacterial Outer Membrane Proteins