The PD 50 test was performed to assess the subunit vaccine potency by following the bovine potency test protocol described by the OIE to test the traditional inactivated FMD vaccines. In this research, the result showed the vaccine potency of the batch immunized with the expressed antigens reached 6.34 PD 50 per dose (Table 4 ). Discussion FMD still threatens world livestock production. Seven distinct serotypes of FMDV have been identified, named A, O, C, Asia I, SAT I, SAT and SAT with none cross immune protection occurring between them. The FMDV serotype Asia which was first isolated in Pakistan is epidemic within Southeast Asia and Indian peninsula, disseminating among Near East, Middle East and Far East [22] . In March 2005, FMDV serotype Asia was found in HongKong (Asia I/HNK/CHA/05 strain). Subsequently, this type of the virus was reported from mainland of China in April 2005 [23] . The P1 sequence of Asia 1/HNK/CHA/05 isolate was aligned and compared with 9 reference sequences. The result confirmed that Asia 1/HNK/CHA/05 has a high identity with nine Asia I reference sequences from 85.9 to 92.6% [24] .