Therapeutic vaccines for human papillomaviruses

Although papillomavirus infections are not very immunogenic there is evidence that the immune system controls the spread of virus and the development of diseases associated with such infections. Certain types of human papillomaviruses (HPV) are the major cause of premalignant and malignant diseases of the anogenital tract, most notably cancer of the uterine cervix, a major health care problem worldwide. Since the viral oncoproteins E6 and E7 are constitutively expressed within the tumor cells, they are considered as suitable targets for attack by T lymphocytes. Several approaches to specifically trigger a cell-mediated immune response have been successful in experimental animals, leading to suppression of HPV-induced tumors. First clinical trials have been completed which raise hopes that a similar effect can also be achieved by therapeutic vaccination of humans.