1. Pulmonary vaccination induces a long-term immune memory response to antigen challenge.
Pulmonary vaccination induces a long-term immune memory response to antigen challenge. Sheep received three vaccinations of 15 μg of influenza antigen and 75 Isco units of Iscomatrix adjuvant, delivered into the deep lung (n = 12). Negative-control unvaccinated sheep (n = 12) received PBS alone. At 6 and 12 months postvaccination, six sheep from each group were challenged in the lung with influenza virus antigen. Serum and BAL fluid were collected 1 week prior to and 1 week after antigen challenge, and anti-influenza virus antibody levels were determined by ELISA. At both 6 and 12 months post-pulmonary vaccination, antigen challenge induced a strong antibody memory response, as indicated by significantly elevated anti-influenza virus antibody levels (*, P < 0.001; ANOVA). Box plots present interquartile ranges (boxed regions) and 10th and 90th percentile values (error bars). n.s., not significantly different (P > 0.05; ANOVA). Antigen challenge induced no increase in titers in samples from unvaccinated controls (not shown).
Ana Vujanic et al. Clin. Vaccine Immunol. 2012; doi: /CVI