Utilization of Ribozymes as Antiviral Agents

Ribozymes are involved in strategies to block gene expression and have been used as agents against viral infections and cancer. Emphasis has been on studies using hairpin and hammerhead ribozymes. The uniqueness of ribozymes is that they posses multiple turnover allowing high efficiency as antiviral agents. Ribozymes have been directed to human immunodeficiency virus (HIV), hepatitis (B, C and E) and human papillomavirus (HPV), the cause of cervical cancer. The mode of action of antiviral ribozymes, their structure and their in vitro effectiveness as inhibitors of HIV, HBV, HCV, HEV and HPV is reviewed. Although ribozymes have been demonstrated as effective antivirals in cell culture and some animal models, clinical studies have been limited. Nevertheless, ribozymes remain as a viable alternative to antisense and RNA interference