Tetanus is an important disease which created by tetanospasmin toxin of Clostridium tetani. In this study we surveyed six important factors including LF, KF, MLD, pH, OD and total protein assay of Harvard 52 (H52), G5 (HG5) and 49205 (H49205) strains of the bacterium to determine which of them were more suitable for use in vaccine production. The mentioned strains were seperatedly reactivated i...