The potential of the ESAT-6 antigen secreted by virulent mycobacteria for specific diagnosis of tuberculosis

J Infect Dis. 1997 May;175(5):1251-4. doi: 10.1086/593686.


Tuberculosis (TB) remains a global health problem in humans and animals, and improved diagnostic methods are needed urgently. This study examined the potential of an interferon-gamma blood test based on a recently identified low-molecular-mass secreted protein antigen, ESAT-6, for early detection of bovine TB. It was found that field cases of bovine TB and experimentally infected cattle exhibited strong in vitro interferon-y responses directed toward this antigen. Of importance, ESAT-6 reactivity was found to discriminate between cattle infected with TB and cattle sensitized by environmental mycobacteria, and the gene encoding this molecule was demonstrated to be absent from >90% of the nontuberculous mycobacterial strains isolated from healthy sensitized cattle. These results demonstrate the feasibility of using single defined antigens for the highly specific diagnosis of TB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Bacterial / analysis
  • Antigens, Bacterial / biosynthesis*
  • Antigens, Bacterial / genetics
  • BCG Vaccine
  • Bacterial Proteins
  • Cattle
  • Cattle Diseases*
  • Diagnosis, Differential
  • Genes, Bacterial
  • Immunization / veterinary
  • Interferon-gamma / blood
  • Mycobacterium avium* / isolation & purification
  • Mycobacterium avium* / pathogenicity
  • Sensitivity and Specificity
  • Skin Tests
  • Tuberculosis / diagnosis
  • Tuberculosis / immunology
  • Tuberculosis / veterinary*
  • Virulence


  • Antigens, Bacterial
  • BCG Vaccine
  • Bacterial Proteins
  • ESAT-6 protein, Mycobacterium tuberculosis
  • Interferon-gamma