Immune response of group 1 mice (treated as indicated in Fig. 4). IgG and IgA antibodies specific to the 5B19 peptide (A, B, E, and F) or TMV (C, D, G, and H) were determined in ELISA. Serum IgG and IgA antibodies were detected with goat anti-mouse IgG or anti-mouse IgA antibodies conjugated with horseradish peroxidase. (A–D) Serum titers of mice immunized with TMV-5B19L; (E–H) Serum titers of the mice immunized with w.t. TMV. Short vertical bars on the x axis indicate the days of immunization. Each line represents the response of a single mouse.