IFNG and tuberculosis: There is a functional overlap between CD4+ and CD8+ T cells: both produce cytokines such as TNF-α and IFN-γ to activate M. tuberculosis infected dendritic cells and macrophages, however CD8+ T cells exhibit strong cyolytic activity enabling them to kill infected phagocytic cells: this activity has been observed in both mouse [12]–[14] and human [15]–[17] tuberculosis.