Mycobacteria
The live attenuated strains M. bovis BCG SSI1331 and M.
bovis BCG Tokyo were used for vaccination and challenge, respectively.
Mycobacteria were grown to mid-log phase in 7H9 medium containing 0.05%
Tween 80 and OADC; bacteria were aliquoted and frozen at
-70oC until further use. Titre of the frozen aliquots
was determined by thawing an aliquot and plating serial dilutions on
7H11 agar plates.