Immunohistochemistry for peripheral blood-born macrophage infiltration. Immunohistochemistry for peripheral blood-born macrophage infiltration. Ccr2rfp/+Cx3cr1gfp/+ mice, in which peripheral blood macrophages are labeled by red fluorescent protein (RFP) whereas microglia are labeled by GFP (Yamasaki et al., 2014). These mice were used to elucidate the contribution of peripheral blood immune cells. There are no RFP-positive cells in either the PBS-pretreated or OVA and Alum (O+A)-pretreated asthma mice. Scale bar, 100 μm. Ryo Yamasaki et al. J. Neurosci. 2016;36:11929-11945 ©2016 by Society for Neuroscience