Mimic peptides bonding specifically with the first and second extracellular loops of the CC chemokine receptor 5 derived from a phage display peptide library are potent inhibitors of experimental autoimmune encephalomyelitis

To obtain mimic peptides that specifically bind with the first and second extracellular loops (ECL1, ECL2) of the CC chemokine receptor 5 (CCR5) and to study their treatment effects on experimental autoimmune encephalomyelitis (EAE) mice. A phage display peptide library was applied to screen peptides that bond with ECL1 and ECL2. ELISA and DNA sequence analysis were used to identify positive clones. EAE mice were treated with synthesized peptides by intraperitoneal injection. Eighteen positive clones were obtained and four peptides with sequences STFTTTL, TPIPQLL, SLPLPKP and QTSSAAL were identified. These peptides could significantly protect against and reduce the severity of EAE. The infiltration of monocytes and lymphocytes into the spinal cord decreased significantly in treated mice, while abundant inflammatory cells and demyelination were observed in spinal cords of EAE mice. CCR5 mimic peptides provided a significant protective effect to EAE mice. These potent inhibitory mimic peptides could be useful in the clinical treatment of multiple sclerosis.