DNA Vaccines to Combat Retroviral Infections

Retroviruses infect a wide range of animal species and cause a variety of diseases including tumours, wasting and auto-immune diseases, immunodeficiency syndromes and aplastic and haemolytic anaemias. Retroviruses are enveloped viruses, with an RNA genome. They use a unique enzyme called reverse transcriptase, an RNA-dependent DNA polymerase that converts the RNA genome into DNA, which then integrates into the host chromosomal DNA. The reverse transcriptase is highly error prone and rapid genetic variation is a feature of this group because the process of reverse transcription lacks "proof-reading" mechanisms, allowing for frequent mutations to occur. Consequently, vaccines against retroviruses are extremely difficult to develop. The human immunodeficiency virus (HIV) is a familiar example of a retrovirus.

Currently, BTI scientists are pursuing new strategies in vaccine development to fight diseases caused by retroviruses, particularly HIV. An on-going project at BTI is the development of DNA-based vaccines for the prevention and therapy of HIV infections in humans. Recent results using proprietary custom-made vaccine prototypes are very promising and BTI researchers are excited about future advanced studies. The results, coupled with the recent success using gene therapy based on a modified, non-infectious HIV construct (News Release: Fighting HIV with HIV), have given significant impetus to BTI’s HIV vaccine development program.