Fig. 1
Vaccine-induced antibody responses. BALB/c mice were immunized with 2 × 108 particles of rAd-HA and rAd-NP plus 1 × 109 particles of either rAd-empty, rAd-IL-18, or rAd-IL-1β. Serum and BALF were collected at day 42 and day 56, respectively. a Virus-specific total Ig and IgA in sera (1:10,000 dilution) and BALF (1:100 dilution) were analyzed in an ELISA coated with inactivated PR8. The median and interquartile range of the relative light units (RLU) is shown. b–d Flow cytometric analyses were performed with 293T cells expressing PR8 NP or HA (b, c; Sera 1:100, BALF 1:20) or HA derived from pH1N1 or H3N2 (d; Sera 1:20). Sera of mice recovered from sublethal pH1N1 or H3N2 infections were used as positive controls. The median MFI with the respective interquartile range is depicted per group. e Neutralizing antibodies against PR8 in sera were analyzed by microneutralization assay. Depicted are the neutralization titers (NT) of individual mice with the median of the group. The dotted line indicates the detection limit of NT = 5. Results represent eight to 12 mice per group for serum tests and seven to ten mice per group for BALF tests of two independent experiments. #p < 0.05 vs. naive; *p < 0.05 vs. HA/NP + empty (data were log-transformed before analysis, one-way ANOVA, Tukey’s post test)
