Abstract
The association of human papillomavirus (HPV) infection and cervical cancer has been demonstrated. The development of a prophylactic vaccine to protect against primary HPV infection may therefore be an efficient means to reduce the incidence of this cancer worldwide. To assess the capacity of a plasmid DNA that expresses the L1 gene of HPV type 16 to induce a protective immune response, mice were immunized by parenteral and oral routes. Animals that received the DNA vaccine intramuscularly, subcutaneously and orally, developed systemic anti‐L1 IgG antibodies. Antibodies developed in mice vaccinated subcutaneously were detectable twelve months post‐immunization. Specific IgA antibodies were also found in vaginal washes from immunized mice. Both systemic and local antibodies proved effective in a surrogate neutralization assay. Splenic T cells extracted from experimental mice showed cytotoxic T lymphocytes (CTL) activity mediated by CD8 + cells. Mice were challenged with a syngeneic melanoma cell line, engineered to express the HPV16‐L1 protein, tumours in vaccinated animals showed slower growth rate, correlated directly with a longer survival of mice. The results suggest that the L1‐based DNA vaccine may be useful for the prevention of primary infections by HPV16. J. Med. Virol. 66:86–95, 2002. © 2002 Wiley‐Liss, Inc.