Natural and induced immunization against CCL20 ameliorate experimental autoimmune encephalitis and may confer protection against multiple sclerosis

Th-17 type immune response that occurs in multiple sclerosis (MS) is linked to CCR6-CCL20 interaction. We confirmed the dependency on CCR6 in EAE development. Vaccination of mice with hCCL20, but not mCCL20, produced anti-murine CCL20 and ameliorated EAE. The EAE clinical score negatively correlated with anti CCL20 levels. A beneficial effect was transferred by sera from hCCL20-immunized mice. Immunized mice with cyclic peptide that include a bacterial outer membrane protein A (ompA), that share homology sequence with hCCL20 produced anti CCL20, anti ompA and anti-cyclic peptide. Immunization of mice with ompA or the cyclic peptide ameliorated EAE. The cyclic peptide inhibited CCL20 activity in an adhesion assay. A significantly higher level of anti CCL20 were found in healthy individuals compared to RR-MS patients. There was no similar difference for anti-CXCL10. Natural or induced immunization against CCL20 confer protection against EAE and may be beneficial in MS.