Fig. 8.
Long-term immunity induced by MN patch skin vaccination. (A) Anti-PR8 serum HA inhibition titers of serum collected 3- and 12-wk postboosting (n = 5). Serum IgG (B) and BAL IgG (C) titers against huM2e were determined with serum samples collected 3- and 12-wk postboosting. (D) Lung physiology in virus challenge infection. Determination of mouse lung virus titers at day 5 after a sublethal dose 0.5 × mLD50 infection with Phi (n = 3). (E) and (F) To determine systemic cellular immune responses, splenocytes were isolated at 5 d after sublethal dose 0.5 × mLD50 infection with Phi. (E) IFN-γ and IL-4 levels in 4M2e and NP-peptide–reactivated splenocytes culture medium were determined via cytokine ELISA (n = 5). (F) 4M2e-specific IgG antibody-secreting cells from recalled splenocytes were analyzed using ELISpot (n = 5). Data are presented as mean ± SD. Statistical significance was analyzed by t test. P values shown in bar charts and N.S. indicates no significance between two compared groups. The experiments of anti-PR8 serum HA inhibition titration assay (A), serum IgG (B), and BAL IgG (C) titration assays were repeated twice with similar results.