Human papillomavirus (HPV), particularly type 16, has been associated with more than 99% of cervical cancers. There are two HPV oncogenic proteins, E6 and E7, which play a major role in the induction and maintenance of cellular transformation. Thus, immunotherapy targeting these proteins may be employed for the control of HPV-associated cervical lesions. Although the commercially available preventive HPV vaccines are highly efficient in preventing new HPV infection, they do not have therapeutic effects against established HPV infection or HPV-associated lesions. Since T cell-mediated immunity is important for treating established HPV infections and HPV-associated lesions, therapeutic HPV vaccine should aim at generating potent E6 and E7-specific T cell-mediated immune responses. DNA vaccines have now developed into a promising approach for antigen-specific T cell-mediated immunotherapy to combat infection and cancer. Because dendritic cells are the most potent professional antigen-presenting cells, and are highly effective in priming antigen-specific T cells, several DNA vaccines have employed innovative strategies to modify the properties of dendritic cells (DCs) for the enhancement of the DNA vaccine potency. These studies have revealed impressive pre-clinical data that has led to several ongoing HPV DNA vaccine clinical trials.
Keywords: DNA vaccines; Human papillomavirus; cervical cancer.