Figure 2.

Plasma OVA-specific IgG and subclass IgG1 Ab response after intranasal exposure to OVA plus silica particles. BALB/c mice were intranasally exposed to PBS (vehicle control), OVA alone or OVA plus silica particles (250 μg/mouse) on days 0, 1, and 2. Plasma was collected on day 21 and analyzed by ELISA to detect the level of (a) OVA-specific IgG and (b) OVA-specific IgG1 Ab responses. Data represent mean absorbance at a wavelength of 450 nm (reference wavelength, 655 nm). N.D., not detected. Data are presented as mean ± SEM (n = 5 to 8); *P < 0.05, **P < 0.01 vs OVA alone; ^††P < 0.01 vs PBS).