Glatiramer acetate (GA), represents an established treatment of relapsing/remitting multiple sclerosis (MS). The mechanisms responsible for the effect of GA are not fully understood. We generated GA-, myelin basic protein (MBP)- and purified protein derivative (PPD)-specific T cell lines from three MS patients and one healthy donor. The GA-specific lines were CD3⁺, CD4⁺, CD8⁻ and produced tumor-necrosis-factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-10 (IL-10) after stimulation with GA in the presence of irradiated peripheral blood mononuclear cells. MBP-specific T cell lines showed an identical phenotype and secreted TNF-α, IFN-γ, IL-4, IL-10, but not IL-6. Co-culture experiments demonstrated, that GA-specific T cell lines have the capability to suppress the proliferation of MBP-specific T cell lines.