Figure 2.

Representative cross-sections from lungs of BALB/c mice vaccinated and infected with virulent Mycobacterium tuberculosis H37Rv. A. Typical lung section from health non infected mice, no pneumonic or infiltrate were detected. B. Lung from mice non vaccinated and challenge with M. tuberculosis. C. Lung from mice vaccinated with heat inactivated Mycobacterium vaccae a closely related Mycobacterial strains. D. Lung from mice vaccinated with BCG Phipps strain. Significant reduction in the tissue damage was seen only in the mice vaccinated with BCG, the use of saprophytic bacilli as vaccine no induce immune response capable to control infection and pneumonic development. Vaccines were evaluated under a mice model of pulmonary tuberculosis (unpublished data) (H:E stain 50×).