underscores the close relationship between T cells and macrophages in the periphery. Interferon-γ produced from Th1 cells was found to be instrumental in polarizing macrophages to M1 [14]. However, the ability to produce these cytokines does not rest solely with T cells. Microglia and astrocytes have also been observed to fill this role [15,16], demonstrating, at least in part, that microglia can control their own polarization through autocrine and paracrine means. In many cases, this response is protective and is downregulated once the damage or pathogen has been dealt with; however, unregulated, long-term, or chronic inflammation can lead to tissue destruction [17].
