Construction and Immunogenicity of the Recombinant attenuated Salmonella of HPV16 under the Control of the in vivo-inducible nirB Promoter

Vaginal tract mucosae were the main place of Papillomaviruses replication and sexually transmission. More than 70% of women suffering from cervical intraepithelular neoplasia do not have HPV-specific antibodies in the genital secretion. Therefore, it is very important to develop vaccines, which mainly induce the mucosal immunity against Papillomavirus infection. An attenuated salmonella-based Papillomavirus vaccine was developed. pET-16 L1E7CTA2B plasmids were constructed by inserting the L1E7 DNA fragment upstream of CTA2B in pET-20b under the control of IPTG-inducible promoter T7. The pNir-16L1E7CTA2B contained the hybrid NirB promoter and were developed by digestion and reassemble of both the T7 promoter of pET-20b and the nirB of pTETnir15, so hybrid nirB-T7 promoter contained the FNR and the basic element (TATA box) form nirB and ribosome-binding site form T7 promoter, could drive the transcription and expression the target genes. The BALB/c mice were inoculated with the pNir-16L1E7- and pNir-16L1E7CTA2