Fig. 3

Experimental schedule and T. spiralis-specific IgG subtype (IgG1 and IgG2a) responses upon immunization. Mice were immunized twice with VLPs as indicated with a 4-week interval. Challenge infection was performed at week 4 after last immunization (a). Enzyme-linked immunosorbent assay (ELISA) plates were coated with T. spiralis antigen, as indicated in Methods. T. spiralis-specific IgG, IgG1 and IgG2a antibody responses in the sera were determined after prime and boost. Significant differences were found between group VLPs alone and group VLP with cholera toxin (CT) (b, c and d, *P < 0.05)