A DNA vaccine encoding MPB83 from Mycobacterium bovis reduces M bovis dissemination to the kidneys of mice and is expressed in primary cell cultures of the European badger (Meles meles)

Nucleic acid (DNA) vaccination against tuberculosis in the European badger (Meles meles) is one approach to addressing the escalating problem of bovin e tuberculosis in Great Britain. The aim of vaccination is to reduce the bu rden of tuberculosis within the badger population and the shedding of Mycob acterium bovis to levels that would break the transmission of infection to cattle. To this end, the vaccine would be required to limit the amount of d isseminated tuberculosis in the badger, especially dissemination to the kid ney from where M bovis can be shed in the urine. A promising candidate DNA vaccine encoding a 26 kDa major antigen (MPB83) of M bovis was evaluated in a mouse model of disseminated M bovis infection. Using the DNA vaccine, pr otection against infection of the kidney was found to be greater than that achieved with the current live vaccine, Bacille Calmette-Guerin (BCG). Kidn ey tissue and skeletal muscle from the badger was used to derive primary ce ll cultures in which to examine the expression of MPB83 following transfect ion with the DNA vaccine. Kidney cortex gave rise to a monotypic culture of epithelial cells whilst the muscle gave rise to a mixed culture of fibrobl asts and myoblasts. During culture the myoblasts differentiated into multin ucleated myotubes, verified by immunofluorescent detection of mammalian des min. Successful expression Of MPB83 by transfected epithelial and myotube c ells was confirmed by immunofluorescence using a monoclonal antibody specif ic to the protein. These observations fulfil the early requirements for the development of a DNA vaccine for badger tuberculosis.