Summary:Glatiramer acetate (GA) (Copolymer-1, Copaxone, Teva, Israel, YEAK) is a polypeptide-based therapy approved for the treatment of relapsing-remitting multiple sclerosis. Most investigations have attributed the immunomodulatory effect of GAs to its capability to alter T-cell differentiation. Specifically, GA treatment is believed to promote development of Th2-polarized GA-reactive CD4 ϩ T-cells, which may dampen neighboring inflammation within the central nervous system. Recent reports indicate that the deficiency in CD4
FoxP3ϩ regulatory Tcells in multiple sclerosis is restored by GA treatment. GA also exerts immunomodulatory activity on antigen presenting cells, which participate in innate immune responses. These new findings represent a plausible explanation for GA-mediated T-cell immune modulation and may provide useful insight for the development of new and more effective treatment options for multiple sclerosis.