FIG 3.

Mouse anti-STa IgA antibody titers, detected in fecal suspension samples of each immunized or control mouse. Anti-STa IgA in fecal suspension samples of the immunization groups and the control group (five mice per group) were titrated in ELISA with STa-ovalbumin conjugates (10 ng per well, Costar plates) as the coating agent and HRP-conjugated goat anti-mouse IgA (1:1,000) as secondary antibodies. The antibody titer was calculated from the highest dilution of a fecal suspension sample that produced an ELISA OD of >0.3 above the background, and results are presented in a log₁₀ scale. Each dot represented a mouse IgA antibody titer, and the bar was the mean titer of the group. Groups (labeled on the x axis) were mouse groups immunized with each fusion antigen and the control group (“−” column), of which fecal suspension samples were titrated for anti-STa IgA antibodies.