FIG. 3.

Antibody isotype profiles. Anti-TTFC antibody isotype profiles on day 54 post-oral immunization or day 48 post-intranasal (i.n.) immunization with recombinant spores expressing CotB-TTFC (RH103) or nonrecombinant B. subtilis spores (PY79) as described in the legend to Fig. 2. TTFC-specific IgG1, IG2a, IgG2b, IgG3, IgM, and IgA isotypes were determined by indirect ELISA. Sera from a naïve control group were also assayed. The end-point titer was calculated as the dilution of serum producing the same optical density as a 1/40 dilution of a pooled preimmune serum. Data are presented as arithmetic means and error bars are standard deviations.