ABSTRACT
Viruses are in many respects molecular syringes that specialise in injecting their genes into living cells. There is an enormous variety of viruses and they attack every organism from bacteria to humans. Their modus operandi is to find a suitable organism to infect, gain entry to an appropriate cell and hijack its resources to make viral proteins and viral genetic material. Developing and testing the safety of viral vectors is an expensive business and, so far, most research has concentrated on a handful of viruses with a narrow range of characteristics. Viruses related to AIDS that can integrate their genetic cargo into the chromosome of target cells, and so theoretically require only one treatment, are extremely desirable as gene vectors. Our bodies contain so many billions of individual cells that it is not too surprising to hear that mutated cells frequently arise capable of producing a tumour.
