la hipótesis de que las limitaciones en el funcionamiento de los macrófagos y los linfocitos T desempeñan un papel muy importante en la diseminación de la enfermedad.Palabras clave: IFN-γ, Macrófagos, Mycobacterium bovis, PPDB, Coctel proteico. Abstract:Macrophages are considered one of the main immune mechanisms of resistance to mycobacterial infections. In addition, experimental and clinical data indicate that IFN-γ is essential for host defence against M. tuberculosis. The aim of this study was to identify macrophage capacity on controlling Mycobacterium bovis infection and lymphocyte IFN-γ production from cattle naturally exposed to M. bovis. Peripheral blood monocyte-derive macrophages from naturally infected cattle were evaluated for their ability to control the intracellular growth of M. bovis BCG. Besides, whole blood cells were stimulated with PPDB and ESAT-6+CFP-10 protein cocktail. Results show a disparity in host susceptibility to Mycobacterium bovis. A M. bovis BCG survival rate of 80 to 150 % in macrophages from naturally infected cattle was observed. While the IFN-γ production towards Purified protein derivative bovine (PPDB) and the protein cocktail was 2.5 and 2.0 optic density index, respectively. Though our data do not support a correlation between the host susceptibility to M. bovis and the production of IFN-γ in naturally infected cattle, the hypothesis that the limitations in the functioning of macrophages and T lymphocytes play a very important role in the spread of the disease cannot be discarded.