Fig. 2: AP205 cVLPs boosts the induction of HCV specific IgG in immunized mice.

A A schematic illustrating the immunization schedule and serum collection from BALB/c mice. Dose-response ELISAs against either monomeric (B) or oligomeric (C) sE2 of week 9 mouse serum samples collected from animals immunized either with (B) monomeric or (C) oligomeric sE2 alone or on cVLPs. ELISAs were done in single replicates using anti-mouse IgG coupled to HRP and subsequently a colorimetric TMB substrate signal was detected. Binding results were assessed by four parameter curve fitting to calculate OD₅₀ values. Data is represented with median value of inverse OD₅₀ values of purified IgG from individual animals. D, E Dose-response neutralization of HCV recombinant J4 (genotype 1b) HCVcc was done in three replicates using mouse IgG and was evaluated in FFU reduction assays on Huh7.5 cells. Following 48 h of infection the cells were fixed and FFUs were visualized using HCV anti-NS5A antibody followed by anti-mouse antibody coupled to HRP followed by DAB staining of FFUs. Results were normalized to non-infected control cells and neutralization was assessed by four parameter curve fitting to calculate IC₅₀ values. If 50% neutralization was not reached at the highest tested dose then IC₅₀ values were interpolated if neutralization at highest dose reached a minimum of 30% and increased to at least 50% at 3 mg/ml. Data is represented with median value of inverse IC₅₀ values of purified IgG from individual animals. F The IC₅₀ values from panels D and E were pooled into groups where antigen was either coupled to VLPs or not. Statistical significance testing was done using non-parametric Mann-Whitney tests (Graphpad Prism 9.2.0) and the significance threshold was set at 95%.