IFNG and Granuloma: In an initial study with cattle (n = 3), aerosol MBO Ravenel (~105 CFU) elicited immune responses (i.e., DTH and IFN-γ) to MBO antigens (Figure 1); yet, 2.5 months after challenge, tuberculous lesions were not detectable in two animals, and a single small granuloma was detected in the lung of the third animal.