Fig. 7: Analysis of IFN-γ secretion and Th1/Th2 skewing in Ad26.S.PP immunized mice.
a Naïve BALB/c mice were immunized with either 108 or 1010 vp of Ad26.S.PP, Ad26.S (N = 10 per group) or with Ad26.Empty (N = 5). Number of IFN-γ producing cells per million splenocytes 4 weeks after immunization as measured by ELISpot. Median responses per group are indicated with horizontal lines. Dotted line indicates the LLOD. Animals with a response at or below the LLOD were put on LLOD and are shown as open symbols. b–e Naïve mice (BALB/c, N = 6 per group) were immunized with either 1010 vp of Ad26.S.PP or 50 µg of S protein adjuvanted with 100 µg Adjuphos (Adju-Phos®). Two weeks after immunization samples were analyzed for antibody and cellular responses. b Number of IFN-γ producing cells per million splenocytes as measured by ELISpot. One mouse excluded due to high background in peptide pool 1 stimulation. Dotted line indicates the LLOD. c Th1 (IFN-γ) over Th2 (IL-4, IL-5, and IL-10) cytokine ratios measured by multiplex ELISA after stimulation of splenocytes with SARS-CoV-2 S protein peptides. d S protein-specific IgG binding antibody titers were measured by ELISA. e Ratio of IgG2a/IgG1 S protein-specific antibody titers as measured by IgG2a and IgG1 ELISA. Dotted line indicates an IgG2a/IgG1 ratio of 1. Animals with a response at or below the LLOD in the IgG2a ELISA are shown as open symbols. Horizontal lines denote group medians. Statistically significant differences as determined by t-test from ANOVA (a), z-test from Tobit ANOVA (c, d), or Mann–Whitney U test (b, e) are indicated by asterisks **p < 0.01; ***p < 0.001. LLOD lower limit of detection, vp virus particles.
