To amplify the transferrin-binding protein 2 (Tbp2) gene from Actinobacillus pleuropneumoniae (App) by polymerase chain reaction (PCR), a pair of primers were designed according to sequence Z46774 of A. pleuropneumoniae serotype 5. The amplified DNA fragment (1642 bp) was cloned into pMD18-T and sequenced. The sequencing result showed that the homology was 99.8% compared with the reference sequence. The target fragment of the positive clones was inserted into pET-32a and transformed in Escherichia coli BL21 (DE3). After its induction, the fragment was expressed in E. coli. The Western blotting results were positive.
