CTL responses to a DNA vaccine encoding E7 gene of human papillomavirus type 16 from an Iranian isolate.

BACKGROUND Cervical cancer is the most prevalent tumor in developing countries and the second most frequent cancer among female population worldwide. Specific human papillomaviruses and, most notably, HPV types 16 and 18 are recognized as being causally associated with cervical carcinomas. The early HPV type 16 genes, E6 and E7, directly participate in the in vitro transformation of primary human keratinocytes and represent an excellent target for immune therapy of HPV related disease. OBJECTIVE The aim of this study was the evaluation of the efficacy of a DNA vaccine containing human papillomaviruse type 16 E7 gene (Iranian isolate) in induction of CTL responses in an animal model. METHODS In this study, the expression vector containing HPV type 16 E7 gene was constructed and chosen as a model antigen in the development of a therapeutic DNA vaccine in an animal model. CTL responses, cytokine assay, lymphocyte stimulation test, CD4 and CD8 staining and flowcytometry were done for evaluating of the immune responses. RESULTS Our findings indicate that the target DNA vaccine can induce an E7-specific CTL response, which is important in the lysis of infected tumor cells, compared to negative control (p<0.005) after in vivo immunization in the mouse system. CONCLUSION The developed vaccine may be promising as an anti-cancer vaccine.