FIG. 7.

Isotype profile of serum antibodies following i.n. or f.p. immunization. Serum samples were obtained 2 to 3 weeks after the last immunization of mice. The mice were immunized i.n. either with the native flagellin (squares) or with recombinant flagellin (diamonds) or f.p. with recombinant flagellin (circles). Results with preimmune serum are indicated by triangles. The coating antigen for the ELISA microplate was either the recombinant 9B peptide-1 flagellin (empty symbols) or 9B peptide-1 (filled symbols). The second antibody reacts specifically with different isotypes of the serum antibodies (IgG1, IgG2a, IgG2b, and IgG3) as indicated.