CD274 and Autoimmunity: Although it has been described that B7-H1 expression is critical for myeloid DC (CD45HIGHCD11b+CD11c+) regulation of IFN-γ and IL-17 production during autoimmunity [16]; based on our findings, it remains unclear which APC (microglia, macrophages, or subsets of DCs) populations is/are most dominant for regulating CD4+ and CD8+ T cell responses through B7-H1:PD-1 or B7-DC:PD-1 interactions during acute and chronic TMEV-IDD in vivo.