Table 1.

Prophylactic HCV vaccine studies in chimpanzees

Vaccine (Genotype sequence used) (Number of animals vaccinated)	Immunogenicity	Challenge Inoculum* Dose (CID50§)	Outcome	Ref.
DNA prime and protein boost (using C, gpE1, gpE2 and NS3)	Induced specific T-cell responses and antibody to E1 and E2.	GT 1b	Modifies infection, protects from chronic infection	32
(GTs 1a (core, NS3) and 1b (core, E1E2, NS3))		Homologous	1 resolved infection
(N=2)		25CID50	1 developed persistent infection
Adjuvant: Alum
DNA prime and Recombinant Adenovirus expressing core, E1,E2 and NS3 to NS5B	Induced specific T-cell responses and anti-E2 antibody (neutralizing)	GT 1b	Modifies infection, protects from chronic infection	27
(GT 1b)		Homologous	1 protected from infection
(N=6)		100CID50	1 resolved infection
Adjuvant: Human IL-12-expressing plasmid			4 developed persistent infection
DNA prime and Recombinant VV expressing NS3,NS5A,NS5B	Induced specific T-cell responses	GT 1a	Modifies infection	63
(GT 1a)		Homologous	1 developed persistent infection
(N=1)		100CID50
Adjuvant: CpGs and VV expressing co-stimulatory molecules B7.1; ICAM-1; LFA-3..
DNA prime and Recombinant Adenovirus expressing NS3 to NS5B	Induced specific T-cell responses	GT 1a	Modifies infection, protects from chronic infection	31
(GT 1b)		Heterologous	4 resolved infection
(N=5)		100CID50	1 developed persistent infection
Adjuvant: None
DNA prime and rMVA boost (using C, gpE1, gpE2 and NS3)	Induced specific T-cell responses and antibody to E1 and E2.	GT 1b	Modifies infection, protects from chronic infection	70
(GT 1b)		Homologous	1 resolved infection
(N=4)		25CID50	3 developed persistent infection
Adjuvant: None
Recombinant VV core, E1, E2, p7, NS2 and NS3	Induced specific T-cell responses. Weak anti-E1E2 response.	GT 1b	Modifies infection, protects from chronic infection	28
(GT 1b)		Homologous	4 resolved infection
(N=4)		2.5 and 24CID50†
Adjuvant: None
DNA prime and Recombinant Adenovirus expressing NS3,NS5A,NS5B	Induced specific T-cell responses	GT 1a	Modifies infection or protects from chronic infection	64
(GT 1a)		Homologous	1 resolved infection
(N=2)		100CID50	1 developed persistent infection
Adjuvant: Human IL-12-expressing plasmid
Recombinant gpE1/gpE2	Induced antibodies to E1E2	GT 1a	Protects against infection or chronic infection	53
(GT 1a)		Homologous	5 protected from infection	52
(N=21)		10 to 100CID50	14 resolved infection
Adjuvant: MF59 or MF75 oil-water emulsion			2 developed persistent infection
Recombinant gpE1/gpE2 + HVR1 peptides	Induced antibodies to E1E2 and HVR1	GT 2	Protects from chronic infection	54
(GT 2)		Homologous	1 resolved infection
(N=1)		10 CID50
Adjuvant: Complete and Incomplete Freund’s
DNA vaccine expressing E2 protein	Induced antibody and T cell responses to E2.	GT 1a	Modifies infection, protects from chronic infection	33
(GT 1a)		Homologous	2 resolved infection
(N=2)		100CID50
Adjuvant: None
Recombinant gpE1/gpE2	Induced antibodies and cellular responses to E1E2	GT 1a	Delayed/modified infection	71
(GT 1a)		Homologous	1 developed persistent infection
(N=1)		100CID50
Adjuvant: RIBIs
Recombinant VLPs containing C, E1 and E2	Induced specific T-cell responses. No detectable anti-E1E2 Ab response.	GT 1b	Modifies infection, protects from chronic infection	34
(GT 1b)		Homologous	4 resolved infection
(N=4)		100CID50
Adjuvant: AS01B (N=2)

Homologous and heterologous refer to the same or different GT, respectively.

^§CID50=50% chimpanzee infectious doses;

^†Animals erroneously received 2.5CID50 which did not lead to infection in control animals. Animals were then challenged with 24CID50.