Putative TB vaccine candidates were selected from lists of genes induced in response to in vivo-like stimuli, such as low oxygen and carbon starvation or growth in macrophages, and tested as plasmid DNA vaccines for their ability to protect against Mycobacterium tuberculosis challenge in a guinea pig aerosol infection model. This vaccination method was chosen as it induces the Th1 cell-mediated immune response required against intracellular pathogens such as M. tuberculosis. Protection was assessed in the guinea pig model in terms of mycobacteria present in the lungs at 30 days post-challenge. Protection achieved by the novel candidates was compared to BCG (positive control) and saline (negative control). Four vaccines encoding for proteins such as PE and PPE proteins, a zinc metalloprotease and an acyltransferase, gave a level of protection that was statistically better than saline in the lungs. These findings have enabled us to focus on a sub-set of vaccine candidates for further evaluation using additional vaccination strategies.
Bibliographical noteFunding Information:
This study was funded by the Department of Health, UK. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health. We acknowledge the support of the staff in the Biological Investigations Group at HPA, Porton Down, the technical expertise of Kim Hatch, and members of the TB group for constructive discussions on vaccine candidate selection.
- DNA vaccine
- Guinea pig
- Mycobacterium tuberculosis