Increased vaccine efficacy against tuberculosis of recombinant Mycobacterium bovis bacille Calmette-Guérin mutants that secrete listeriolysin
Leander Grode, … , Bärbel Raupach, Stefan H.E. Kaufmann
Leander Grode, … , Bärbel Raupach, Stefan H.E. Kaufmann
Published September 1, 2005
Citation Information: J Clin Invest. 2005;115(9):2472-2479. https://doi.org/10.1172/JCI24617.
View: Text | PDF
Research Article Infectious disease

Increased vaccine efficacy against tuberculosis of recombinant Mycobacterium bovis bacille Calmette-Guérin mutants that secrete listeriolysin

Abstract

The tuberculosis vaccine Mycobacterium bovis bacille Calmette-Guérin (BCG) was equipped with the membrane-perforating listeriolysin (Hly) of Listeria monocytogenes, which was shown to improve protection against Mycobacterium tuberculosis. Following aerosol challenge, the Hly-secreting recombinant BCG (hly+ rBCG) vaccine was shown to protect significantly better against aerosol infection with M. tuberculosis than did the parental BCG strain. The isogenic, urease C–deficient hly+ rBCG (ΔureC hly+ rBCG) vaccine, providing an intraphagosomal pH closer to the acidic pH optimum for Hly activity, exhibited still higher vaccine efficacy than parental BCG. ΔureC hly+ rBCG also induced profound protection against a member of the M. tuberculosis Beijing/W genotype family while parental BCG failed to do so consistently. Hly not only promoted antigen translocation into the cytoplasm but also apoptosis of infected macrophages. We concluded that superior vaccine efficacy of ΔureC hly+ rBCG as compared with parental BCG is primarily based on improved cross-priming, which causes enhanced T cell–mediated immunity.

Authors

Leander Grode, Peter Seiler, Sven Baumann, Jürgen Hess, Volker Brinkmann, Ali Nasser Eddine, Peggy Mann, Christian Goosmann, Silke Bandermann, Debbie Smith, Gregory J. Bancroft, Jean-Marc Reyrat, Dick van Soolingen, Bärbel Raupach, Stefan H.E. Kaufmann

×

Figure 1

Options: View larger image (or click on image) Download as PowerPoint
Hemolytic activity of and phagosomal acidification by ΔureC hly+ rBCG. (...
Hemolytic activity of and phagosomal acidification by ΔureC hly+ rBCG. (A) RT-PCR analysis of BCG-strains for Hly-secretion. Secretion of Hly was analyzed by RT-PCR using RNA from parental BCG (lane 1), rBCG ΔureC (lane 2), hly+ rBCG (lane 3), and ΔureC hly+ rBCG (lane 4). Shown is 1 out of 3 representative experiments. (B) Hemolysis by hly+ rBCG and ΔureC hly+ rBCG but not parental BCG. Sheep red blood cells were incubated with hly+ rBCG (open triangles), ΔureC hly+ rBCG (closed triangles), parental BCG (closed squares), or L. monocytogenes (open diamonds), or remained untreated (open circles). At indicated time points, aliquots were taken and release of hemoglobin was determined by optical absorption as measurement for lysis of red blood cells. Shown is 1 representative experiment of 4. (C–F) Primary murine macrophages were infected with parental BCG (C and D) or ΔureC hly+ rBCG (E and F) for 2.5 hours. Images on the left show BCG stained with DID (signal shown in green). Images on the right show a pseudocolor representation of the fluorescence ratio in the blue and green channels with the Lyso Sensor Yellow/Blue dye. Images are merged with a black-and-white phase contrast image. Note that not all bacteria in each batch were stained due to the poor solubility of DID and its high affinity to the hydrophobic cell wall. Scale bar: 20 μm.