Production of Polyclonal Antibody to the HPV58 E7 Protein and Its Detection in Cervical Cancer

The persistent infection of high-risk human papillomavirus (HPV) is one of the most common causes of cervical cancer worldwide, and HPV type 58 is the third most common HPV type in eastern Asia. The E7 oncoprotein is constitutively expressed in HPV58-associated cervical cancer cells and plays a key role during tumorigenesis. To study the biological function of HPV58 E7 and to characterize E7 protein-host cell interactions, we cloned the human HPV58 E7 gene and produced specific E7 antibodies. The HPV58 E7 gene was cloned into a prokaryotic expression vector, pGEX-4T2. The recombinant plasmid pGEX-4T2-(HPV58-E7) was transformed into Escherichia coli DH5α and expressed as a fusion protein containing a GST tag. After purification and removal of the GST affinity tag, the E7 protein was used as an antigen for the production of antiserum in rabbits. The specificity of the purified HPV58 E7 antibody was detected by western blotting, immunofluorescence and immunohistochemistry analysis. These methods demonstrated that the polyclonal antibody could specifically recognize the endogenous and the recombinant HPV58 E7 proteins. Immunohistochemistry analysis indicated that the E7 protein was localized in the nucleus of cervical cancer cells.