A Preliminary Investigation Of The Adjuvant Effects Of Interleukin-2 And Rehmannia Glutinosa Polysaccharide On A Vaccine Of Cervical Cancer

Objective: To provide new approaches for the prevention and treatment of cervical cancer through investigating respective adjuvant effects of interleukin-2(IL-2) produced by a recombinant non-replicating vaccinia virus RNTV1175IL2H6 Lac Z and rehmannia glutinosa polysaccharide(RGP) on cervical cancer’s vaccine from a recombinant vaccinia virus RVVJHPV16E7E6 in TC-1 model mice which are the cervical cancer treatment models expressing human papillomavirus 16 E6, E7, ras gene transformation.Methods: First, identifying the constructed RNTV1175IL2H6 Lac Z, and testing the biological activity in vitro of IL-2 produced by it. Second, evaluating the cellular immune responses, the IL-2 levels, and the antitumor abilities in the TC-1 model mice immunized intraperitoneally with RNTV1175IL2H6 Lac Z and RVVJHPV16E7E6. Third, estimating the cellular immune responses, the humoral immune response, the number of CD4+ and CD8+ cells, and the inhibition effects of tumor growth in the mice immunized by intramuscularly injecting RVVJHPV16E7E6 and by gavage RGP.Results: 1) PCR results confirmed we successfully constructed the RNTV1175IL2H6 Lac Z which could be continuously sub-cultured for 12 generations with IL-2 gene stably inherited in CEF cells. As to IL-2 expressed by the virus, results of Western Blot showed that its molecular weight accorded with that of standard IL-2. Additionally, the results of MTT assays indicated the biological activity in vitro of IL-2 from the virus reached 8.79 IU/ml. 2) Results indicated the combined vaccine of RVVJHPV16E7E6 and RNTV1175IL2H6 Lac Z not only had a tendency to enhance E7-specific cellular immune responses, but also made the body of mouse IL-2 levels increased in the immunized mice. Furthermore, on the antitumor abilities, the vaccine achieved a 30% reduction rate of tumor formation. 3) RGP as the adjuvant of RVVJHPV16E7E6 in this study was failed to strengthen the immunological competence, given no responses of specific cellular immune and no change in the number of CD4 +, CD8 +, and CD4 +/CD8 +. However, the rate of tumor protection against cervical cancer in the TC-1 mice reached up to 90%.Conclusions: 1) The RNTV1175IL2H6 Lac Z as the adjuvant of RVVJHPV16E7E6 not only promotes the secreting of IL-2, but also improves the anti-tumor ability, which has a promising application in the biological treatment of cervical cancer. 2) RGP is not beneficial to be as a plant-derived adjuvant RVVJHPV16E7E6, but enhanced inhibition effects of tumor growth are presented, which lays the basis of researches on its anti-tumor mechanism in the future.