Studies of the underlying immune mechanisms of multiple sclerosis (MS) in children may shed light on the initial events of MS pathogenesis. We studied T cell responses to myelin peptides in 10 pediatric MS patients (PMS), 10 pediatric healthy controls (PHC), 10 adult MS patients (AMS) and 10 adult healthy controls (AHC). A significantly higher proportion of divided CD4+ T cell responses in response to myelin peptides by the CFSE assay in PMS compared to PHC at both concentrations of myelin peptide tested (t test, 95% CI, p=0.0067 for MP1; p=0.0086 for MP10), and between PMS and AMS (p=0.0012 at 1μg/mL of myelin peptides, p<0.0001 at 10μg/mL) was found. In addition, T cells with a central memory phenotype producing IL-17 were increased in PMS compared to PHC (p<0.05). IL-7 levels in culture supernatants were elevated in PMS compared to PHC and AMS (t test<0.01).