Essential role of tumor necrosis factor-alpha in the induction of hepatitis B virus (HBV) specific cytotoxic T lymphocyte: Senji Kasahara, Kazuki Ando, Kuniaki Saito, Gifu University School of Medicine, Gifu Japan; Kenji Sekikawa, National Institute of Animal Health, Tsukuba Japan; Mitsuru Seishima, Hisataka Moriwaki, Gifu University School of Medicine, Gifu Japan2001