Isocitrate lyase encoding plasmids in BCG cause increased survival in ApoB100-only LDLR-/- mice.

We studied the role of isocitrate lyase in the interaction between Mycobacterium bovis BCG and mice. ApoB100-only LDLR-/- (B6;129S-ApoBtm2SgyLdlrtm1Her/J) mice were inoculated with M. bovis BCG harbouring plasmids carrying the gene for isocitrate lyase. The presence of ~29 times more copies of this gene resulted in a higher bacterial yield in the spleens and lungs of the infected mice. The spleen was 3-4 times heavier, and in the spleen the bacteria survived over 10 days longer than did the bacteria with the control plasmid. Propionate was less toxic for bacteria carrying icl plasmids in vitro. This recombinant BCG can be a possible vaccine candidate.