Single-Dose Mucosal Immunization with a Candidate Universal Influenza Vaccine Provides Rapid Protection from Virulent H5N1, H3N2 and H1N1 Viruses
Figure 5
IgA is not required for protection after i.n. rAd immunization.
Groups of 6 IgA−/−-BALB/c mice were immunized with 5×109 particles each of A/NP-rAd and M2-rAd i.n. or i.m., or 1×1010 particles of B/NP-rAd i.n. (A) IgG responses against M2e were measured by ELISA using serum obtained 2 weeks after immunization. The dashed line indicates limit of detection. (B) Antigen-specific T-cell responses at 3 weeks post-immunization were determined in peripheral blood pooled from these animals by IFN-γ ELISPOT using NP147–155, NP55–69 or M2e2-24 peptides as stimulus. Unstimulated cells (no peptide) were used as a control. Bars show mean ± SEM of triplicate wells for each group per stimulus. At one month post-immunization, animals were challenged with 104 TCID50 (100 LD50) of A/FM and monitored for survival (C) and weight loss (D). Error bars in weight loss graph indicate mean ± SEM. Statistically significant differences in weight loss (P<0.05) were observed between A/NP+M2-rAd i.n. and i.m. at days 2–15, between A/NP+M2-rAd i.n. and B/NP-rAd at days 3–13, and between A/NP+M2-rAd i.n. and B/NP-rAd at days 2, 3, 9 and 13.