Kinetics of the appearance of OVA-specific serum IgG in BALB/c female mice immunized intranasally with OVA and DOTAP/DC-chol liposomes.

<p>BALB/c female mice were immunized intranasally with PBS alone, DOTAP/DC-chol liposomes (0.4 μmol/mouse) alone, OVA (5 μg/mouse) alone, or OVA (5 μg/mouse) plus DOTAP/DC-chol liposomes (0.4 μmol/mouse) once weekly (days 0, 7, 14, 21, and 28). Serum was collected every week immediately prior to immunization (days 0, 7, 14, 21, 28, and 35). Anti-OVA IgG, IgG1, and IgG2a levels in serum were determined by ELISA assay. The data are obtained from at least three independent experiments and are expressed as the mean ± the standard error. Significance was assessed with the Kruskal–Wallis with Dunn’s post–hoc test: *<i>p</i><0.05, **<i>p</i><0.0001.