FIG. 1.

Effects of IL-12 administered i.n. on systemic antibody responses to PspA. BALB/c mice were immunized i.n. on day 0 with PspA, treated i.n. with either IL-12 or PBS vehicle on days 0, 1, 2 and 3, and boosted with PspA on days 14 and 28. On day 28, the mice also received IL-12 or PBS vehicle. Serum anti-PspA antibody levels on day 35 were determined by isotype-specific ELISA using PspA-coated microtiter plates. Each line represents binding of antibody from an individual mouse (four mice per group). Differences in binding between mice immunized with PspA and IL-12 and those immunized with PspA and PBS vehicle were significant (P < 0.05) for total antibody (Ab) and IgG1 and (P < 0.1 for IgA and IgG2a). O.D., optical density.