Protection Elicited by Two Glutamine Auxotrophs of Mycobacterium tuberculosis and In Vivo Growth Phenotypes of the Four Unique Glutamine Synthetase Mutants in a Murine Model

Abstract
We generated four individual glutamine synthetase (GS) mutants (ΔglnA1, ΔglnA2, ΔglnA3, and ΔglnA4) and one triple mutant (ΔglnA1EA2) of Mycobacterium tuberculosis to investigate the roles of GS enzymes. Subcutaneous immunization with the ΔglnA1EA2 and ΔglnA1 glutamine auxotrophic mutants conferred protection on C57BL/6 mice against an aerosol challenge with virulent M. tuberculosis, which was comparable to that provided by Mycobacterium bovis BCG vaccination.