6 Adeno - Associated Viral Vectors

Adeno-associated virus (AAV) is a non-pathogenic humanDNAviruswith a unique profile of biological properties that have been of interest to molecular virologists for many years (Berns, 1990; Carter, 1990; Carter et al., 1990). Recently,AAV has also attracted interest as a vector for gene transfer (Carter, 1992; Flotte, 1993a; Hermonat andMuzyczka, 1984; Tratschin et al., 1984). In a general sense, AAV is unique among viruses currently being used for gene transfer in that it is a native human virus which is not known to cause disease, and may, in fact, suppress the induction of tumors by other viruses (Cukor et al., 1975; DeLaMaza and Carter, 1981; Hermonat, 1989, 1991; Khlief et al., 1991; Kirschstein et al., 1968; Labow et al., 1987; Mayor et al., 1973; Ostrove et al., 1981). There is a natural enthusiasm to develop therapeutic applications of a virus which is naturally symbioticwith its human host. This must be tempered by careful attention to how the biology of the virus may be altered as its genome is re-engineered to make it into a vector.