Figure 3. Immunogenicity and efficacy of VLP-immunisation against LCMV-challenge in young and old mice with/without Tx or latent MCMV-infection.

Young (5 months old, 3 months p.i.) and old C57BL/6 mice (18 months old, 15 months p.i.) with or without Tx and latent MCMV-infection were immunised with 10 µg VLP-GP33 s.c. Thereafter, the GP33-specific CD8⁺ T cell response was measured on day 7 (A) by tetramer staining and the Qb-specific IgG titres were quantified by ELISA on day 10 (E) and day 20 (F) in the blood. On day 21, all mice were challenged with 2×10³ pfu LCMV-WE i.v. Eight days after LCMV-challenge the GP33-specific CD8⁺ T cell response was determined by ICS in the lung (B) and LCMV-titres were determined in the spleen (C) and in the lung (D) by plaque assay. Circles indicate individual mice, horizontal lines represent the median (A–D). Vertical bars show the mean of an experimental group, error bars correspond to the SEM (E, F). The dotted line shows the detection limit of the assay. 4–5 mice per group were included. ANOVA followed by Bonferroni post-analysis was preformed to test for significant differences (* p<0.05; ** p<0.01; ns = not significant).