Fig. 4.

Humoral immunity elicited by MCMVHA protects against IAV challenge. JHT and BALB/c mice (A–D) or C57BL/6 mice (A, E–G) were immunized i.p. with 2 × 10⁵ PFU of MCMV^HA. Twenty-eight days (A, E–G) or 120 days (A–D) after immunization, the mice were challenged with IAV (1100 FFU, i.n.). A Setup of the experiment. B Titers of HA-specific antibody in serum samples on Day 5 after IAV challenge determined by HAI. C IAV lung titers on Day 5 post-challenge. D Body weight loss upon IAV challenge. All data are pooled data from two independent experiments. E Body weight loss upon IAV challenge of MCMV^HA- or control-immunized (MCMV^∆m157) JHT mice. F Comparison of body weight loss of MCMV^HA-immunized JHT and control mice. G Titers of IAV in the lungs on Day 5 post-challenge. Each symbol represents an individual mouse sample, and the skull-and-crossbones symbols indicate dead animals. The horizontal lines indicate the means, and the error bars indicate the standard error values. Two-way ANOVA (for Fig. 4D) or Mann–Whitney U tests (for Fig. 4B and C) were used for statistical analysis. ** p < 0.01, *** p < 0.001, **** p < 0.0001