Table 1.

Characteristics of Vectors for Gene Therapy

	Retrovirus	Adenovirus	Adeno-associated virus	Liposome
Advantages	Stable integration	High virus titer	Integrates into chromosome 19	Less immunogenic
	Large insert capacity	Highly efficient transfer	Targets nondividing cells
	Biology well investigated	Targets nondividing cells
Disadvantages	Low titer	Host immune response	Biology not well known	Low efficient transfer
	Infects only dividing cells	Transient expression	Small insert capacity
Application	Ex vivo strategy	Direct injection	Direct injection	Direct injection
	Initially well used	Ex vivo transfer