Table 2.

Viral Delivery Methods.

Feature	Retroviral Vector	Lentiviral Vector	Adenoviral Vector	Adeno-Associated Viral Vectors
Particle size (nm)	100 nm	100	80–120	20–30
Genetic material	ssRNA (positive strand)	ssRNA (positive strand)	dsDNA	ssDNA
Cloning capacity (Kb)	7–8	7–9	Up to 36	≈2.4–4
Chromosomal Integration	Yes	Yes	No	Yes (in about 1–10% of infected cells)
Immune response induction	Moderate	Low	Moderate–High (due to large size)	Low
Comments:	Low titers and can only primarily infect dividing cells	High efficiency and can infect both dividing and nondividing cells	High transduction efficiency in both dividing and nondividing cells	Long lasting expression and predictable chromosomal integration but small packaging ability