Gene therapy in pancreatic cancer

Table 1 Comparison of characters of common viral vectors

Virus	Viral genome	Insertion capacity	Host range of infection	State of integration into host genome	Efficiency of gene transfection and expression	Immunogenicity	Titers of preparation in vitro(PFU/mL)	Bio-safety
AdV	Double-stranded DNA	38 kb	Broad spectrum (both dividing and non-dividing cells)	No integration	High	High	1011-1012	Safe
AAV	Single-stranded DNA	4.9 kb	Broad spectrum	Site-specific integration on chromosome 19q13.3	High	Low	1012, dependent on helper virus	Safe
RV	Single-stranded RNA	8 kb	Dividing cells only	Integrate randomly	Low	Low	106-107	Risk of insertional mutagenesis
Lentivirus	Single-stranded RNA	8 kb	Broad spectrum	Integrate randomly	High	Low	109-1010	Risk of viral infection and insertional mutagenesis
Pox virus	Souble-stranded DNA	25 kb	Broad spectrum	No integration	High	High, function as immunologic adjuvant	106-107	Safe
HSV	Double-stranded DNA	15-30 kb	Nerve cells and epithelial cells, especially neuro- tropic speciality	No integration	High	Moderate	1011-1012	Risk of viral infection