A Novel Chimpanzee Adenovirus Vector with Low Human Seroprevalence: Improved Systems for Vector Derivation and Comparative Immunogenicity
Figure 4
Infectivity of recombinant adenovirus vector preparations can affect immunogenicity.
(A–C) IFN-γ Spleen ELISpot responses after immunisation with HAdV-5 TIPeGFP doses based on viral particles (VP) or infectious units (IU). Balb/c mice were immunised intramuscularly with either (A) 107 viral particles or (B) 107 infectious units of one of two independent preparations of HAdV-5 TIPeGFP. Responses to CD8+ epitope Pb9 were assayed two weeks post immunisation. Asterisk indicates p<0.05. (C) Titers per ml and particle to infectious unit (P:I) ratios of the two CsCl-band purified vector preparations. (D) Immunogenicity of TIPeGFP expressing Y25 based vectors with different E4 modifications is comparable despite the vectors having different P:I ratios. Balb/c mice were immunised intramuscularly with 108 infectious units of Y25 vectors with either i) a native E4 locus (ChAdY25) ii) Ad5E4Orf6 expressed at E4 (ChAdY25-A) or iii) the clinical ChAdY25-E vector. IFN-γ Spleen ELISpot was performed as in A-C. P:I ratios of vector preparations were as follows; ChAdY25 131, ChAdY25-A 17.4, ChAdY25-E 13.4.