Inhibitory effect of the HPV-16mE6δ/mE7/TBhsp70δ vaccine on oral squamous cell carcinoma.

Aim: To evaluate the inhibitory effect of a recombinant human papillomavirus (HPV) fusion protein vaccine on oral squamous cell carcinoma (OSCC). Materials and Methods: An animal model of OSCC was established using human peripheral blood lymphocyte reconstituted nonobese diabetic/severe combined immunodeficiency mice. HPV vaccine was subcutaneously injected into mice after tumor establishment. Tumors and spleens were measured, weighed and stained with hematoxylin and eosin. Lymphocyte subpopulations and cytotoxicity were analyzed with flow cytometric and cytotoxic T lymphocyte assay. Results: The average weight and volume of tumors were significantly lower in the vaccine group than in the control group from day 27. Mice in both groups had high percentages of human CD3(+) and CD3(+) CD8(+) T lymphocytes. An elevated percentage of human CD3(-)CD16(+)56(+) natural killer cells was found in the vaccine group. Moreover, vaccine increased the infiltration of human CD3(+) and UCHL-1(+) cells in tumor tissues and enhanced cytotoxicity. Conclusions: The HPV fusion protein vaccine induces tumor cell death, lymphocyte infiltration and therefore suppresses tumor growth and protects against OSCC.