IFNG and infection: Th1 cells, which produce interleukin (IL)-2, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α), are the major effectors of phagocyte-mediated host defense, protective against intracellular pathogens, and Th2 cells, which produce IL-4, IL-5, IL-6, IL-13, and IL-10, are important in allergic responses and protection against infection of helminthic parasites [23, 24].