MRC1 and Stroke: To understand the roles of Sig-1R knockout on the polarization of macrophages/microglia after stroke, we first compared the pro-inflammatory phenotypic marker CD16 (Figure 4A) and anti-inflammatory marker CD206 (Figure 4C) expression in macrophages/microglia from the ischemic striatum at 5 d after reperfusion between WT and Sig-1R knockout mice.