CD4 and infection: Clearly TNF-α participates in the establishment of acquired immunity of the Th1 response, with the generation of IFN-γ-producing CD4+ cells and CD8+ cytotoxic cells, two outcomes crucial for the complete killing of the intracellular Brucella. TNF-α produced a synergistic effect in presence of IFN-γ for the ultimate clearance of the infection [45].