Improving sensitivity for serodiagnosis of tuberculosis using TB16.3-echA1 fusion protein

Tuberculosis (Edinb). 2014 Sep;94(5):519-24. doi: 10.1016/j.tube.2014.06.006. Epub 2014 Jul 24.

Abstract

This study aimed at developing and assessing the fusion proteins with enhanced sensitivity to detect antibodies in plasma as a diagnostic method for tuberculosis. DNA fragments encoding TB16.3 and echA1 gene regions corresponding to proteins TB16.3 and echA1 from Mycobacterium tuberculosis were amplified through PCR. Through a series of restrictions and ligations two novel fusion constructs TB16.3-echA1 and TB16.3-tnPstS1 were produced and expressed in Escherichia coli. These were screened for detection of antibodies in human plasma. The individual antigens TB16.3, echA1 and tnPstS1 and the fusion protein TB16.3-tnPstS1 and TB16.3-echA1 showed sensitivities of 29%, 25.5%, 42.8%, 40.0% and 47.2%, respectively. Lower sensitivity in case of TB16.3-tnPstS1 seems to be due to the structural arrangement between the two proteins, which is likely to mask several of their epitopes. The higher sensitivity of TB16.3-echA1 appears to be due to lesser interaction between the two proteins thus allowing free availability of epitopes for binding antibodies. 64% of TB patients were found positive for either one of the two fusion proteins TB16.3-echA1 and TB16.3-tnPstS1. This study indicates that the novel fusion protein TB16.3-echA1 has a potential in serodiagnosis of TB with improved sensitivity and reliability.

Keywords: Immunoassay; Serodiagnosis; Tuberculosis.

MeSH terms

  • Animals
  • Antibodies, Bacterial / blood*
  • Antigens, Bacterial* / chemistry
  • Antigens, Bacterial* / genetics
  • Bacterial Proteins* / chemistry
  • Bacterial Proteins* / genetics
  • Biomarkers / blood
  • Case-Control Studies
  • Cloning, Molecular
  • Enzyme-Linked Immunosorbent Assay*
  • Humans
  • Models, Molecular
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / immunology*
  • Predictive Value of Tests
  • Protein Conformation
  • Rabbits
  • Recombinant Fusion Proteins* / chemistry
  • Recombinant Fusion Proteins* / genetics
  • Reproducibility of Results
  • Serologic Tests / methods*
  • Tuberculosis, Pulmonary / blood
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / immunology

Substances

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Proteins
  • Biomarkers
  • Recombinant Fusion Proteins
  • TB16.3-echA1 fusion protein