Generation of tumor-specific cytolytic T lymphocytes from peripheral blood of cervical cancer patients by in vitro stimulation with a synthetic human papillomavirus type 16 E7 epitope

OBJECTIVE: Approximately 90% of squamous carcinomas of the cervix harbor the human papillomavirus and type 16 has been detected in nearly 50% of cases. Recent studies in mice have shown that the human papillomavirus type 16 E7 oncoprotein contains peptide epitopes that are processed and presented in association with a major histocompatibility antigen for recognition by cytolytic T lymphocytes. We investigated whether an epitope from human papillomavirus type 16 E7 could be used to generate specific human cytolytic T lymphocytes in patients with cervical carcinoma. STUDY DESIGN: After radiation therapy, three patients with antigen HLA-A2 and with locally advanced cervical cancer underwent leukapheresis. Epitope-specific cytolytic T lymphocytes were generated from the peripheral blood mononuclear cells by in vitro stimulation with autologous peripheral blood mononuclear cells pulsed with a human papillomavirus type 16 E7, HLA-A2-restricted, synthetic peptide, E7_11-20 (YMLDLQPETT). RESULTS: In two patients cytolytic T lymphocytes were capable of E77_11-20-specific, HLA-A2-restricted cytolysis of the peptide-pulsed, HLA-matched, T2 target cell line. Cytolytic T lymphocytes from one of these patients also demonstrated specific cytolysis against the HLA-A2⁺, HPV-16⁺ CaSki cervical cancer cell line but did not lyse either HLA-A2⁺, HPV-16 MS-751 cells or HLA-A2⁺, HPV-16 HT-3 cells. CONCLUSIONS: These experiments demonstrate that novel cytolytic T lymphocytes that recognize a human papillomavirus type 16 E7 epitope can be generated by using the peripheral blood mononuclear cells from irradiated patients with cervical cancer. In addition, because CaSki cells were specifically lysed by the cytolytic T lymphocytes, these data indicate that the peptide E77_{11- 20} is endogenously processed and presented on the cell surface of the CaSki cells. The demonstration of epitope-specific lysis of cytolytic T lymphocytes of HPV-16⁺ cervical cancer cells supports further efforts to develop human papillomavirus peptide-based vaccines or antigen-specific adoptive immunotherapy for the prevention and treatment of cervical carcinoma.