Janet L. Macpherson, Julie A. Ely, Lun-Quan Sun, Geoff P. Symonds

Johnson & Johnson Research Laboratories, GPO Box 3331, Sydney, NSW 2001 Australia

TABLE OF CONTENTS

1. Abstract

2. Introduction

2.1 The infectious cycle of HIV-1
2.2 Gene therapy approaches to HIV-1
2.3 Designing and testing ribozymes

2.3.1 Choice of the RNA target site
2.3.2 Testing ribozymes by in vitro cleavage
2.3.3 Testing ribozymes in cell culture

2.4 Ribozyme-mediated inhibition of a murine retrovirus

3 Anti-HIV-1 ribozymes

3.1 The potential application of ribozymes to the treatment of AIDS
3.2 Design and testing of anti-HIV-1 ribozymes

3.2.1 Anti-HIV-1 ribozymes in cell culture

3.2.2 Specificity of anti-HIV ribozymes

3.3 Towards an anti-HIV ribozyme gene therapeutic
3.4 Current Phase I clinical trials of an anti-HIV ribozyme

4. Conclusion

5. Acknowledgments

6. References

1. ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) is the primary etiologic agent for Aquired Immune Deficiency Syndrome (AIDS). HIV-1 is a lentivirus, a separate genus of the Retroviridae, which are complex RNA viruses that integrate into the genome of host cells and replicate intracellularly. Ribozymes are catalytic RNA molecules with enzyme-like cleavage properties, that can be designed to target specific RNA sequences within the HIV-1 genome. In addition to the genomic RNA, several RNA intermediates, including splice variants, can be targeted by a single ribozyme. We and others have demonstrated the ability of ribozymes to suppress HIV-1 replication in a variety of cultured cells. Ribozyme gene therapy for HIV-1 infection is a therapeutic approach that offers several potential advantages over conventional therapies in that it can potentially impact on both viral load and restoration of the immune system. Ribozyme gene therapy may be used as an adjunct to chemotherapeutic drugs, effecting viral suppression, and facilitating immune restoration without problems of patient compliance. Currently, an anti-HIV-1 ribozyme is being tested in two separate Phase I Clinical Trials.