Abstract:

Objective The soluble protein recombinant Streptococcus mutans surface protein（rPAc） was expressed in Escherichia coli（E.coli） after the optimization of inducing conditions. The antiserum against rPAc was obtained by immunizing mice with the purified rPAc. Methods The soluble expression of rPAc in E.coli was further optimized by means of different culture conditions. Polyclonal antibody was made by immunizing mice with purified rPAc. Western blot and enzyme linked immunosorbent assay（ELISA） were carried out to identify the immunocompetence of the antibody. Results The highest soluble expression level of rPAc was obtained at Luria-Bertani（LB） medium（pH=7.2） when optical density（OD600nm） was 0.6 after being induced at 30 ℃ for 4 h and the concentration of isopropyl β-D-1- thigalactopyranoside（IPTG） was 1.0 mmol·L-1. The titer of the mice antiserum against rPAc was about 1∶6 000 by ELISA analysis, and rPAc could be specifically recognized by Western blot analysis. Conclusion This study proved that rPAc can be effectively expressed as a soluble form in E.coli, and the high specific polyclonal antibody of rPAc was proved to be prepared, which shed light on further research of DNA prime-protein boost inoculation.

Key words: Streptococcus mutans surface protein, prokaryotic expression, antibody preparation