| Cervical cancer is the most common neoplasm of gynecology oncology. It is confirmed that Human papilumavirus is the etiology factor of the cervical cancer. Owing to HPV protein, which has strong antigenicity, expressing in the cervical cancer cells, cervical cancer is the one of the gynecology cancers that are the most suitable for immunotherapy.It is found that absence or lower expression of costimulatory B7 is the key factor for rumors to escape from the kill of the immune system. Because of the costimulatory B7 effectively present the tumor antigen to T lymphocytes by providing the second signal, which is the key signal to present antigen to T lymphocytes.DNA vaccines can induce the process of the tumors escaping from the immune tolerance by a special way of presenting antigen to T lymphocytes. HPV early gene E6, E7 is the key etiology factor of cervical cancer, which has strong antigenicity and can identify antigen location coding by human T lymphocytes, and is most attractive target for cervical cancer immune therapy.Several researches provided that B7 can enhance the anti tumor effect of the CEA and 3 -gal DNA vaccines.At present, there is not a kind of animal model of cervical cancer for immune therapy with HPV as the target to estimate the experiment validity. A key two-way metastasis animal model of murine cervical cancer U14 was set up in 1987 in our country. On the base of the model, to set up a mice model of cervical cancer expressing HPV can provide an important tool for immune therapy research target to HPV.Objective: To investigate the effects of U14 cell vaccines transfected with B7 and HPV16 E6/B7 chimeric recombinant DNA vaccines in inducing anti tumor immune response to murine cervical cancer in Chinese 615-strain mice as a prevent and treatment strategy.Methods: B7-l gene was transfected into 615-strain mice's cervix carcinoma cell line No. 14 (U14) to set up a highly-expressed mB7-l U14 cell clonal strains (B7+U14), which were prepared as a B7+U14 vaccine to prevent and treat 615-strain mice cervical cancer model transplanted U14. Survival and tumor sizes of all mice were recorded. In vitro cytotoxicity assay: Mice were immunized with B7+U14 or U14 vaccine and 2 weeks later, spleen cells of those mice were obtained and cultured for 2 days. The Cytotoxicity of these cells against the U14 was detected by 5-diphenyl tetrazolium bromide assay.We transfected HPV 16 E6 and E7 gene into mouse cervix carcinoma cell strain NO. 14 (U14) to set up the high expression E6 and E7 U14 (E6+U14, E7+U14) and transplanted those cells into inbred 615-strain mice both subcutaneously and intraperitoneally to observe the growth behavior and metastasis of them.We created chimeric E6/B7 gene and subcloned it into the pRC/CMV vector. Using these DNA vaccines, we prevented and treated 615 modle mice transplanted E6+U14 in vivo respectively. Survival and tumor sizes of all mice were recorded and their lymphnode and lung's metastases were detecting by pathogenic. The Cytotoxiaty of the spleen T cells of those mice immuned with HPV E6 and E6/B7 DNA recombinant vaccines against the E6+U14 and U14 was detected by MTT assay.Results: B7+U14 vaccines can effectively prevent 615-strain mice cervical cancer model and treat the partly tumor-bearing mice. It was effective for tumor-bearing mice only when the tumor diameters were<3 mm. When the diameters were >3 mm, it was not efficacious to inject B7+U14 vaccine(p<0.05). In vitro cytotoxicity assay, cytotoxic T lymphocytes induced by B7+U14 vaccines had a higher cytotoxicity against U14 than that induced by U14 vaccine (F=310.8, p<0.001).The durations of tumor appearance after the mice wer transplanted subcutaneously with wild type U14, E6+U14, and E7+U14 respectively, were 5-7 d, 11-14 d, and 8-10 d (p<0.05); The mean survival durations of mice were 29 d, 43 d, and 35 d respectively (p<0.05); Metastasis could be found both in lymph nodes ( 90%, 30%, and 40% respectively) and lungs (60%, 10%, and 20% respectively). After intraperitoneal i...
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