Figure 1.

Functional characterization and cross-reactivity of sera from vaccinated pigs. (A) Neutralizing activity against various IAV of anti-HA sera from pigs that were vaccinated with VSV*ΔG(H1) of Belzig/01. (B) Inhibitory activity of anti-NA sera from pigs vaccinated with VSV*ΔG(N1) of Belzig/01 against virus spread in cell culture. (B). In (A,B), titers were defined as the last serum dilution that inhibited infection or allowed only single cell infection. The sera were collected 3 weeks after the second booster immunization. Mean and SD of six replicates from a representative experiment out of two is shown. (C–H) Different viruses were tested in a pDC-based opsonization assay based for antibody-enhanced pDC activation and IFNα secretion following stimulation with immune complexes. Sera from naive, VSV*ΔG(H1), VSV*ΔG(N1), and WIV vaccinated pigs were serially diluted and tested for their ability to enhance IFNα of pDC stimulated by various IAV. A representative experiment is shown. (I–K) Mean and SD of all pDC-based opsonization assays performed. Opsonizing titers were defined as the highest serum dilution resulting in a significantly higher IFN-α production by enriched pDC as compared with naive serum. Each symbol represents an independent experiment. Asterisks (*) indicate significant differences calculated with the Wilcoxon test (p < 0.05).