Cloning and expression of the L1 immunogenic protein of human papillomavirus genotype 16 by using Lactobacillus expression system

Abstract Cervical cancer is the second most common cancer worldwide, after breast cancer. The agent of more than 90% of cervical cancer is Human papillomavirus (HPV). More than 100 various HPV with about 40 types of infective genotypes are identified and among these genotypes, near 15 carcinogenic genotypes are recognized as high risk. Moreover, genotypes 16 and 18 are the main agents of HPV related cancers. Today, HPV vaccines are available, but they could not cover all high-risk genotypes and also, they are really expensive. The aim of this study was to clone and express the L1 protein of human papillomavirus genotype 16 appropriately in the expression host Lactobacillus. The current study is the first step to prepare a live vaccine based on probiotic strain. In this study, the L1 gene of HPV genotype 16 was cloned to Lactobacillus pNZ7021 plasmid and its expression was assessed. So, the DNA of HPV genotype 16 was extracted from a clinical sample and by using specific primers, the L1 gene was amplified and inserted to the pBluescript cloning vector. Then, both amplified L1 gene and pNZ7021 were digested with BanII and HindIII restriction enzymes and ligated. Subsequently, the ligation product was transformed to Lactobacillus cremoris expression host. The recombinant host was cultured and L1 gene expression was evaluated by western blot method. The L1 gene amplifies by PCR successfully. The cloning of the L1 gene in the pBluescript vector was appropriate. The subcloning of the L1 fragment into the expression vector PNZ7021 was correct. Western blot results confirmed of L1 protein. It is suggested that the expression of the L1 protein-coding gene from human papillomavirus genotype 16 in the probiotic strain Lactobacillus cromoris could be considered as an immunogen, and this study needs further investigation.