Fc-based delivery system enhances immunogenicity of a tuberculosis subunit vaccine candidate consisting of the ESAT-6:CFP-10 complex

Mol Biosyst. 2016 Jun 21;12(7):2189-201. doi: 10.1039/c6mb00174b.

Abstract

Tuberculosis (TB) remains a major global health threat despite chemotherapy and Bacilli Calmette-Guérin (BCG) vaccination. Therefore, a safer and more effective vaccine against TB is urgently needed. This study evaluated the immunogenicity of a recombinant fusion protein consisting of early secreted antigenic target protein 6 kDa (ESAT-6), culture filtrate protein 10 kDa (CFP-10) and the Fc-domain of mouse IgG2a as a novel subunit vaccine. The recombinant expression vectors (pPICZαA-ESAT-6:CFP-10:Fcγ2a and pPICZαA-ESAT-6:CFP-10:His) were transferred into Pichia pastoris. After SDS-PAGE and immunoblotting, the immunogenicity of the recombinant proteins was evaluated in mice. When both recombinant proteins (ESAT-6:CFP-10:Fcγ2a and ESAT-6:CFP-10:His) were used for vaccination, Th1-type cellular responses were induced producing high levels of IFN-γ and IL-12. However, the Fc-tagged recombinant protein induced more effective Th1-type cellular responses with a small increase in IL-4 as compared to the BCG and ESAT-6:CFP-10:His groups. Moreover, mice primed with BCG and then supplemented with ESAT-6:CFP-10:Fcγ2a produced the highest levels of IFN-γ and IL-12 in immunized groups. The findings indicate that when Fcγ2a is fused to the ESAT-6:CFP-10 complex, as a delivery vehicle, there could be an increase in the immunogenicity of this type of subunit vaccine. Therefore, additional investigations are necessary for the development of appropriate Fc-based tuberculosis vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen-Presenting Cells / immunology
  • Antigen-Presenting Cells / metabolism
  • Antigens, Bacterial / chemistry
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / immunology*
  • BCG Vaccine / immunology
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / immunology*
  • Cloning, Molecular
  • Cytokines / metabolism
  • Disease Models, Animal
  • Female
  • Gene Expression
  • Immunization
  • Immunoglobulin Fc Fragments / genetics
  • Immunoglobulin Fc Fragments / immunology*
  • Mice
  • Models, Molecular
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / immunology
  • Protein Conformation
  • Protein Engineering
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology*
  • Tuberculosis / immunology
  • Tuberculosis / metabolism
  • Tuberculosis / prevention & control
  • Tuberculosis Vaccines / genetics
  • Tuberculosis Vaccines / immunology*
  • Vaccines, Subunit / genetics
  • Vaccines, Subunit / immunology*

Substances

  • Antigens, Bacterial
  • BCG Vaccine
  • Bacterial Proteins
  • CFP-10 protein, Mycobacterium tuberculosis
  • Cytokines
  • ESAT-6 protein, Mycobacterium tuberculosis
  • Immunoglobulin Fc Fragments
  • Recombinant Fusion Proteins
  • Tuberculosis Vaccines
  • Vaccines, Subunit