FIG. 3.

Persistence of MYC1551 and MYC1552 within bone marrow macrophages. In this representative experiment, 5 × 10⁴ macrophages were infected with 5 × 10⁴ viable bacilli and growth was measured over time. (A) M. bovis BCG 1173P2 or the BCG auxotroph (MYC1552) was used to infect the macrophages. (B) An M. tuberculosis virulent strain (MT103), its auxotroph counterpart (MYC1551), or MYC1551 harboring plasmid pMJ111 (carrying the purC gene) was used to infect the macrophages. Each point represents the geometric mean ± SEM of six (experiment with M. bovis BCG) or four (experiment with M. tuberculosis) independent cultures.