Recently we reported (Mehra et al., 2013), that lung granulomas from Mycobacterium bovis Bacille
Calmette–Guérin (BCG)-vaccinated cynomolgus macaques exhibit upon challenge with M. tuberculosis
a more balanced expression of a- and b-chemokines, relative to comparable samples from shamvaccinated
animals by comparative transcriptomics. Here, we studied the recruitment of immune cells
to blood and lungs in M. tuberculosis-infected macaques as a function of prior BCG-vaccination.
Vaccination initially enhanced the levels of both macrophages and lymphocytes in blood. In contrast,
significantly more CD4+ lymphocytes were later recruited to the lungs of sham-vaccinated animals
compared with earlier times/BCG vaccinated animals. BCG-vaccination had a short-lived impact on the
anti-M. tuberculosis response. M. tuberculosis continued to replicate in the lung even in the wake of
increased CD4+ T cell recruitment to primate lungs, indicating that immune subversive mechanisms
are key to its survival in vivo.