Figure 3: A single-dose of MCMV^S provides inflationary immunogenicity in aged mice.

(A) Schematic image of the experimental setup. Created with BioRender.com. (B) Pseudovirus neutralization titers that resulted in a 50% of reduction of SARS-CoV-2 infection (PVNT₅₀). Sera of 6 (n=10), 12 (n=19) and 24 (n=7) weeks MCMV^S-immunized mice were tested against the Index (Wuhan; grey), Beta (blue), Omicron BA.1 (red) and Omicron BA.4/5 (orange) SARS-CoV-2 strains. Each symbol indicates an individual mouse. Solid horizontal lines show the median and the dotted line indicates the detection limit. Pie charts indicate the percentage [%] of animals, that responded (black) or non-responded (grey) with nAb titers. (C-D) SARS-CoV-2 Spike specific IgG response against the Index and Omicron BA.1 variants in murine sera after 6, 12, and 24 weeks post-immunization. (C) Total IgG and (D) IgG affinity measured by antibody binding [AUC] in presence of graded amounts of NaSCN using ELISA. Statistical significance for was calculated using Welch’s t test (two-tailed) (* p < 0.05, ** p <0.01).