Mutational Analysis Of L1 Protein And Development Of Virus-like Particles Vaccine Of Human Papillomavirus Type 11

The epidemiology studies had manifest the relationship of HPV infection with Condyloma acuminatum, cervical intraepithelial neoplasia and cervical cancer. HPV 6 and 11 are low-risk types associated with the majority of cases of genital warts. About 90% gential wart are caused by HPV6,11. So the marketability of a vaccine against HPV11-related disease was with good social and economic benefits.It is reported that the L1 protein of HPV can assemble into viru-like particles in vitro. The purified VLPs are morphologically identical to natural HPV virons and retain the natural neutralization epitope of HPV. So it is regarded as the most hopful vaccine candidate. In this study, HPV11 L1 and it's mutants were expressed in non-fused form in prokaryotic expression system, and the N-terminal deletion and critiacal aa mutation were studied to manifest their relationship to HPV11 L1 expression level and VLP assemble efficiency.The N-terminal deletion study showed that the N-terminal deletion didn't affect VLPs assemble when the number of deleted aa wasn't more than 16. But the N-terminal deletion affect the expression level of HPV11 L1. The mutant has the four AA deleted has the highest expression level.According to genebank, the HPV11 L1 sequences has a variation in the position of 364.In most cases the AA of this position is Glu but in some cases is Lys. In this study, it is comfirmed that the property of these two protein were so different. Site mutation show that the variation of AA364 didn't affect the expression level of HPV11 L1,but it affect the VLPs assemble.The mutation of aa364 to Gln,Asp,Arg,Phe,Gly and Leu show that the side chains of aa affect the expression level and VLPs assemle obviously. The molecular model of HPV11 L1 show that aa364 locates in theβ-sheet of L1. The computer mutation analysis show that the side chain of 364 aa form H bond with other aa.Accorcding to the mutation study, the HPV11 L1 with Glu in the position of 364 was selected to prophylactic HPV11 vaccine development.The processes of ferment,purification and VLPs assemble were established and the HPV11 vaccien is obtained. The animal experiment show that the vaccine can elite high titer neutralization antibodies in rat and the antibodies has obvious cross reaction with HPV6.After all,this study provided the structure information for HPV11 L1 protein property ,VLPs assemble study and HPV11 vaccine design. In this study the prophylactic HPV vaccine was developed and some useful information for the development of HPV6,11 chemeric vaccine were provided.