Fig. 1: Generation and characterization of DelNS1-H5N1 vaccines.

A Illustration of construction and generation of DelNS1-H5N1 vaccines. NCR, non-coding region. DCP: deletion of polybasic cleavage site. B Growth kinetics of DelNS1-cH5N1 and DelNS1-mH5N1 at 33 °C were analyzed in MDCK cells inoculated at a multiplicity of infection (MOI) of 0.01 (n = 3), and viral titers of DelNS1-cH5N1 and DelNS1-mH5N1 were measured in day 8 embryonated chicken eggs 48 h after inoculation with different initial doses (n = 3). Viral supernatants or allantoic fluids were collected and titrated by plaque assay in MDCK cells. C Virulence of DelNS1-cH5N1 and DelNS1-mH5N1 was examined in mice. Mice were inoculated intranasally with DelNS1-cH5N1 (10⁶ pfu, n = 8) or cattle H5N1 (5000 pfu, n = 8), DelNS1-mH5N1 (10⁶ pfu, n = 8) or mink H5N1 (10⁴ pfu, n = 8). Body weights were observed for 14 days. D Mice were inoculated intranasally with DelNS1-cH5N1 (10⁶ pfu, n = 3) or cattle H5N1 (5000 pfu, n = 4), with virus titers in lungs, nasal turbinates (NT) and brain tissues of mice being examined at day 2, day 4 and day 6 post infection. LOD limit of detection. Data represents mean values ± standard deviation (SD) of results. N/A not available. Statistical comparisons between means were performed by Student’s t-test (two-tailed). Cartoons were created in BioRender. Wang, P. (2025) https://BioRender.com/n81t049. Source data are provided as a Source Data file.