EAE model

Female mice (7–8 weeks old) received an HGT injection 3 days before EAE induction and were divided into 3 groups as follows: mice received HGT injection of plasmid DNA encoding IL-15 gene; mice received HGT injection of plasmid DNA encoding IL-15ΔE6 gene; mice received HGT injection of minicircle plasmid. Subsequently, the mice were injected subcutaneously with 300 μg MOG (Sangon Biotech, Shanghai, China) in complete Freund’s adjuvant (Sigma-Aldrich, St. Louis, MO) mixed with 4 mg/ml Mycobacterium tuberculosis (BD Difco, San Jose, CA). 500 ng pertussis toxin (List Lab, Campbell, CA) was injected intraperitoneally on days 0 and 2. Clinical signs were assessed daily as follows: 0, no clinical signs; 0.5, partially limp tail; 1, paralyzed tail; 2, mild hind-limb paresis; 3, severe hind-limb paresis; 4, hind-limb paralysis; 5, hind limbs paralyzed and partial forelimb weakness. The clinical scores were evaluated and recorded in a double blinded fashion.