Gene Therapy for HIV and Chronic Infections

This book centers on gene therapy and gene transfer approaches to prevent or treat chronic virus infections. The main focus is on the Big Three: human immunodeficiency virus (HIV-1), hepatitis B virus (HBV) and hepatitis C virus (HCV). Ample anti-HIV drugs are currently available in the clinic and the development of an effective combination therapy has dramatically improved the lifespan and quality of life of infected individuals. A similar trend can already be recognized for HBV and HCV: the development of multiple (directly acting) antiviral drugs and plans to control or even cure the infection. However, approaches that help prevent infection, or which provide long-lasting treatment (such as a cure) remain important goals. Immunization through gene transfer vehicles encoding immunogenic viral proteins shows promise in preventing infections with complex, highly variable, viruses such as HIV-1 or HCV. Gene therapy applications for virus infections have been discussed since the early 1990's. Whereas a true cure seems difficult to achieve for HIV-1 due to its intrinsic property to deposit its genome into that of the host, such attempts may be within reach for HCV where spontaneous viral clearance occurs in a small percentage of the infected individuals. The prospect of original gene therapy approaches may provide alternative ways to reach the same endpoint by, for example, silencing of CCR5 expression post-transcriptionally. Many alternative antiviral strategies have been developed based on a variety of novel molecular methods: e.g. ribozymes. Some studies have progressed towards pre-clinical animal models and a few antiviral gene therapies have progressed towards clinical trials. This book provides an overview of this rapidly progressing field, while focusing on the interface of gene therapy and immunology/vaccinology.