Live attenuated Salmonella vaccines against Mycobacterium tuberculosis with antigen delivery via the type III secretion system

Infect Immun. 2012 Feb;80(2):798-814. doi: 10.1128/IAI.05525-11. Epub 2011 Dec 5.

Abstract

Tuberculosis remains a global health threat, and there is dire need to develop a vaccine that is safe and efficacious and confers long-lasting protection. In this study, we constructed recombinant attenuated Salmonella vaccine (RASV) strains with plasmids expressing fusion proteins consisting of the 80 amino-terminal amino acids of the type 3 secretion system effector SopE of Salmonella and the Mycobacterium tuberculosis antigens early secreted antigenic target 6-kDa (ESAT-6) protein and culture filtrate protein 10 (CFP-10). We demonstrated that the SopE-mycobacterial antigen fusion proteins were translocated into the cytoplasm of INT-407 cells in cell culture assays. Oral immunization of mice with RASV strains synthesizing SopE-ESAT-6-CFP-10 fusion proteins resulted in significant protection of the mice against aerosol challenge with M. tuberculosis H37Rv that was similar to the protection afforded by immunization with Mycobacterium bovis bacillus Calmette-Guérin (BCG) administered subcutaneously. In addition, oral immunization with the RASV strains specifying these mycobacterial antigens elicited production of significant antibody titers to ESAT-6 and production of ESAT-6- or CFP-10-specific gamma interferon (IFN-γ)-secreting and tumor necrosis factor alpha (TNF-α)-secreting splenocytes.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Administration, Oral
  • Animals
  • Antigens, Bacterial / immunology*
  • Bacterial Proteins / immunology*
  • Cell Line
  • Cytokines / genetics
  • Cytokines / metabolism
  • Epithelial Cells / metabolism
  • Female
  • Gene Expression Regulation / immunology
  • Immunization
  • Immunoglobulin G / blood
  • Immunoglobulin G / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mycobacterium tuberculosis / immunology*
  • Recombinant Fusion Proteins
  • Recombinant Proteins / immunology
  • Salmonella Vaccines / administration & dosage
  • Salmonella Vaccines / immunology*
  • Tuberculosis Vaccines / administration & dosage
  • Tuberculosis Vaccines / immunology*

Substances

  • Antigens, Bacterial
  • Bacterial Proteins
  • Cytokines
  • ESAT-6 protein, Mycobacterium tuberculosis
  • Immunoglobulin G
  • PTD4-apoptin protein
  • Recombinant Fusion Proteins
  • Recombinant Proteins
  • Salmonella Vaccines
  • Tuberculosis Vaccines