ABSTRACT
<p><b>OBJECTIVE</b>To express the fusion protein of glutathione S-transferase (GST) and human Id-2 in E. coli and prepare the polyclonal antibodies against Id-2.</p><p><b>METHODS</b>The coding sequence of Id-2 gene was amplified by RT-PCR from the total RNA of breast cancer tissue. The recombinant plasmid was identified by PCR, restriction endonuclease digestion analysis and sequencing. The fusion protein GST-Id-2 expressed in E. coli following IPTG induction was purified by glutathione-agarose affinity chromatography and used to immunize rabbits to prepare the polyclonal antibodies against GST-Id-2.</p><p><b>RESULTS</b>PCR, restriction endonuclease digestion and sequence analyses showed that the Id-2 gene had been correctly inserted into pGEX-6P-1 vector, and the GST-Id-2 fusion protein expressed had a relative molecular mass of approximately 40,000 as shown by SDS-PAGE. The polyclonal antibodies obtained from the rabbit sera were found to specifically react with purified Id-2 by Western blotting, ELISA and agar gel immunodiffusion (AGP).</p><p><b>CONCLUSION</b>The prepared polyclonal antibodies against Id-2 allow effective Id-2 detection and facilitate further investigation of the structure and antigen epitope of Id-2.</p>