Figure 2. Cx3cr1^GFP/WT;Ccr2^RFP/WT knock-in mice distinguish resident microglia from BM-derived macrophages.

Representative dot plots gated on CD11b⁺CD45⁺ cells from (A) naïve and (B) tumors generated in Cx3cr1^GFP/WT;Ccr2^RFP/WT mice. (A) Magenta and blue circles delineate the CD11b⁺CD45^Hi (blood-derived monocytes and macrophages) and CD11⁺CD45^Lo (resident brain microglia) populations. Their CX3CR1-GFP and CCR2-RFP profiles are shown. (B) TAMs were identified by their CD11b and CD45 expression, and the CD45^Hi and CD45^Lo cells are further gated on RFP (CCR2) and GFP (CX3CR1) positivity. The CD45^Hi population can be stratified into three related but distinct populations, whose Ly6C expression is examined. The CD45^low population (microglia) expressed high level of CX3CR1-GFP, but little to no CCR2-RFP. Quantification of the subpopulations of CD45^Hi or CD45^Lo myeloid cells are described in the Result. N=3 for naïve mice and N=5 tumor bearing mice.