FIG. 5.

Antibody titration from serum and fecal samples of rabbits immunized with pLT₁₉₂:pSTa₁₂ or pLT₁₉₂:pSTa₁₃ fusion antigen. The titers (in log₁₀) of anti-LT were detected in a LT GM1 ELISA using purified CT and antigen, with rabbit antiserum samples (1:50) as the primary antibody. To determine the titers of anti-STa antibody, we used STa ovalbumin conjugates as the antigen and rabbit antiserum and antifecal samples (1:50) as the primary antibodies. HRP-conjugated IgG and IgA antibodies (1:5,000) were used as the secondary antibodies. Optical densities of greater than 0.4 (after subtracting the background reading) were used to calculate antibody titers (in log₁₀). Error bars indicate standard deviations.