High frequency of CD4+ T cells specific for the TB10.4 protein correlates with protection against Mycobacterium tuberculosis infection

Infect Immun. 2006 Jun;74(6):3396-407. doi: 10.1128/IAI.02086-05.

Abstract

TB10.4 is a newly identified antigen of Mycobacterium tuberculosis recognized by human and murine T cells upon mycobacterial infection. Here, we show that immunization with Mycobacterium bovis BCG induces a strong, genetically controlled, Th1 immune response against TB10.4 in mice. BALB/c and C57BL/6 strains behave as high and low responders to TB10.4 protein, respectively. The TB10.4:74-88 peptide was identified as an immunodominant CD4+ T-cell epitope for H-2d mice. Since recent results, as well as the present study, have raised interest in TB10.4 as a subunit vaccine, we analyzed immune responses induced by this antigen delivered by a new vector, the adenylate cyclase (CyaA) of Bordetella pertussis. CyaA is able to target dendritic cells and to deliver CD4+ or CD8+ T-cell epitopes to the major histocompatibility complex class II/I molecule presentation pathways, triggering specific Th1 or cytotoxic T-lymphocyte (CTL) responses. Several CyaA harboring either the entire TB10.4 protein or various subfragments containing the TB10.4:20-28 CTL epitope were shown to induce TB10.4-specific Th1 CD4+ and CD8+ T-cell responses. However, none of the recombinant CyaA, injected in the absence of adjuvant, was able to induce protection against M. tuberculosis infection. In contrast, TB10.4 protein administered with a cocktail of strong adjuvants that triggered a strong Th1 CD4+ T-cell response induced significant protection against M. tuberculosis challenge. These results confirm the potential value of the TB10.4 protein as a candidate vaccine and show that the presence of high frequencies of CD4+ T cells specific to this strong immunogen correlates with protection against M. tuberculosis infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylyl Cyclases / immunology
  • Amino Acid Sequence
  • Animals
  • Antigen Presentation
  • Antigens, Bacterial / immunology*
  • BCG Vaccine / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • Cell Polarity
  • Epitopes, T-Lymphocyte
  • Female
  • Histocompatibility Antigens Class I / immunology
  • Immunization
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • T-Lymphocytes, Cytotoxic / immunology
  • Th1 Cells / immunology
  • Tuberculosis / immunology*
  • Tuberculosis Vaccines / immunology*
  • Vaccines, Subunit / immunology

Substances

  • Antigens, Bacterial
  • BCG Vaccine
  • Epitopes, T-Lymphocyte
  • Histocompatibility Antigens Class I
  • TB10.4 antigen, Mycobacterium tuberculosis
  • Tuberculosis Vaccines
  • Vaccines, Subunit
  • Adenylyl Cyclases