Fig 10.
SciIV are immunogenic, induce protection from homologous infection, and prevent transmission in ferrets. (A to C) Five-month-old male ferrets were inoculated twice at 4-week intervals i.n. with 106 FFU of pH1N1/E3-sciIV or with PBS as a negative control (n = 3). Sera were collected 4 weeks postprime and 4 weeks postboost and evaluated for IgG Abs against total influenza virus protein (A; plotted data represent means ± SEM), recombinant NP from PR8 (B; plotted data represent means ± SEM), or recombinant HA from pH1N1 (C; plotted data represent means ± SEM) by ELISA. Sera from ferrets convalescing from A/California/07/2009 influenza virus infection were used as a positive control (n = 3). (D) Protection from challenge and transmission conferred by pH1N1/E3-sciIV vaccination. Immunized ferrets from the experiments represented in panels A to C were then divided among 6 total housing units and challenged with 106 pH1N1 FFU (direct infection [DI]; squares) 1 day prior to being cohoused with a direct contact (DC; circles) and adjacent to an aerosol contact (AC; diamonds; n = 3/group). Starting 2 days postchallenge and every other day following, nasal washes were collected and used to evaluate levels of replicating challenge virus by IFA. Symbols represent mean virus titers ± SD; the dotted line denotes the limit of detection (20 FFU/ml).