Fig. 2

Serum antibody responses for groups receiving different administration routes; a IP route, b SL route, c IN route, and d PO route. Mice were immunized with the PA antigen displaying spore vaccine, and the serological responses were monitored. *, significant (P < 0.05) difference at each time point versus the previous time point within a group. †,‡, significant (P < 0.05) difference between groups at the same time point. Mean ± standard error. Abbreviation: Naïve, PBS treated group; N spore group, non-recombinant Bacillus subtilis spore treated group; PA spore group, PA antigen displayed Bacillus subtilis spore treated group