CD200 and stroke disorder: In this study, we provide evidence to support the hypothesis that CD200-CD200R1 interactions are important for (1) the peripheral immune control of spontaneous bacterial lung infection post-stroke and (2) downregulating neuroinflammatory responses via (3) attenuation of microglia proliferation and (4) inhibition of monocyte and T cell entry into the ischemic brain and (5) are critical for acute survival and behavioral recovery after stroke.