CCR2 and infarction: In the early phase (phase I) following infarction, Ly-6C(hi) macrophages (which are most abundant in the early phase and have pro-inflammatory function) accumulated in wild-type and CX3CR1-/- mice but were nearly absent in CCR2-/- mice, suggesting early Ly-6C(hi) macrophage accumulation in phase I relies on CCR2 (a receptor for monocyte chemoattractant protein 1, or MCP-1) but does not depend on CX3CR1 (a receptor for fractalkine)63.