CCR5 and multiple sclerosis: Its ligands, CCR3 and CCR5, are primarily found in microglia, with elevated levels in reactive microglia.49  CCL3 is highly correlated with the pathological processes of multiple sclerosis and allergic encephalopathy.50,51 Long-term injection of Ccl3 into the lateral ventricle has been shown to inhibit long-term potentiation and impair both spatial and long-term memory in mice.52  Ogfrl1 encodes a protein related to the opioid growth factor receptor.