The tuberculosis vaccine candidate Bacillus Calmette-Guerin ?ureC::hly coexpressing human interleukin-7 or -18 enhances antigen-specific T cell responses in mice.
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ABSTRACT: Bacillus Calmette-Guérin (BCG), the only approved tuberculosis vaccine, provides only limited protection. Previously, we generated a recombinant derivative (BCG ?ureC::hly), which secretes the pore-forming toxin listeriolysin O (LLO) of Listeria monocytogenes. This vaccine shows superior protection against tuberculosis in preclinical models and is safe in humans. Here we describe two new vaccine strains which express human interleukin-7 (hIL)-7 or hIL-18 in the genetic background of BCG ?ureC::hly to modulate specific T cell immunity. Both strains exhibited an uncompromised in vitro growth pattern, while inducing a proinflammatory cytokine profile in human dendritic cells (DCs). Human DCs harbouring either strain efficiently promoted secretion of IL-2 by autologous T cells in a coculture system, suggesting superior immunogenicity. BALB/c mice vaccinated with BCG ?ureC::hly, BCG ?ureC::hly_hIL7 or BCG ?ureC::hly_hIL18 developed a more robust Th1 response than after vaccination with parental BCG. Both strains provided significantly better protection than BCG in a murine Mycobacterium tuberculosis challenge model but efficacy remained comparable to that afforded by BCG ?ureC::hly. We conclude that expression of hIL-7 or hIL-18 enhanced specific T cell responses but failed to improve protection over BCG ?ureC::hly in mice.
SUBMITTER: Rao M
PROVIDER: S-EPMC3827306 | biostudies-literature | 2013
REPOSITORIES: biostudies-literature
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