Identification of Mycobacterium tuberculosis PPE68-specific HLA-A*0201-restricted epitopes for tuberculosis diagnosis

Curr Microbiol. 2015 Jun;70(6):769-78. doi: 10.1007/s00284-015-0786-x. Epub 2015 Feb 15.

Abstract

PPE68 is a Mycobacterium tuberculosis-specific protein which is absent from the vaccine strains of BCG. A panel of 14 PPE68-derived peptides predicted to bind to HLA-A*0201 was synthesized. The HLA-A*0201 restriction of these peptides was determined in T2 cell line and HLA-A*0201 transgenic mice. The specificity of peptides was assessed in pulmonary tuberculosis (TB) patients using IFN-γ enzyme-linked immunospot (ELISPOT) assay, and immunodominant peptides were further used to evaluate their diagnostic potential in HLA-A*0201-positive pulmonary TB patients. 13 out of 14 peptides were identified as high-affinity binders. Of these peptides, 12 peptides induced significant IFN-γ-secreting T cell response in transgenic mice and 9 peptides were efficiently recognized by peripheral blood mononuclear cells of 10 HLA-A*0201-positive TB patients. Four immunodominant HLA-A*0201-restricted epitopes (PPE68126-134, PPE68133-141, PPE68140-148, and PPE68148-156) were recognized by the most of 80 HLA-A*0201-positive TB patients (81, 86, 74, and 84 %, respectively). These epitopes may be used for a potential diagnosis of M. tuberculosis infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / immunology*
  • Bacterial Proteins / metabolism
  • Enzyme-Linked Immunospot Assay
  • Epitopes, T-Lymphocyte*
  • HLA-A2 Antigen / metabolism*
  • Humans
  • Interferon-gamma / metabolism
  • Mice, Transgenic
  • Mycobacterium tuberculosis / immunology*
  • Mycobacterium tuberculosis / isolation & purification*
  • Sensitivity and Specificity
  • T-Lymphocytes / immunology
  • T-Lymphocytes / microbiology
  • Tuberculosis / diagnosis*
  • Tuberculosis / microbiology

Substances

  • Bacterial Proteins
  • Epitopes, T-Lymphocyte
  • HLA-A*02:01 antigen
  • HLA-A2 Antigen
  • PPE68 protein, Mycobacterium tuberculosis
  • Interferon-gamma