To elucidate the isoform-dependent effects of apoE on EAN, we used human apoE 2, 3, and 4 transgenic (Tg) mice immunized with P0 peptide 180-199 to induce EAN, along with macrophage culture, T cell proliferation test, flow cytometry and ELISA, etc. to investigate the effects of apoE isoforms on the functions of macrophages and T cells both in naive conditions and during EAN.