Final answer:
IFN-γ (Interferon-gamma) is the cytokine produced by activated macrophages that promotes Th1 cell differentiation during Mycobacterium infection, supporting the immune system's response against intracellular pathogens.
Step-by-step explanation:
The cytokine that is produced by activated macrophages and promotes the differentiation of Th1 cells during Mycobacterium infection is IFN-γ (Interferon-gamma). IFN-γ is a key cytokine for the innate and adaptive immunity against viral and intracellular bacterial infections and for tumor control. The TH1-mediated immune response is crucial for defending against intracellular pathogens like Mycobacterium tuberculosis, as this response activates macrophages to become more efficient in their killing of intracellular bacteria. IFN-γ is one of the cytokines secreted by Th1 cells that stimulates and enhances the ability of macrophages to phagocytize pathogens and produce chemicals that promote inflammation.