Fig. 5.

Mouse feeding strategy and detection of COE-specific antibody. Protein extracts of transgenic rice calli expressing COE–Co1 fusion protein and wild type were concentrated by precipitating with ammonium sulfate for mouse oral immunization. Each mouse in the experimental group (n = 5) was gavaged with 2 ml of PBS buffer containing 40 μg of COE–Co1 fusion protein in total of 10 time feeds with an interval of 1 week (a). Blood and fecal samples were collected 10 days after 4, 6, 8, and 10-week feedings. The mouse sera and fecal samples were diluted 100-fold and 4-fold, respectively, and used to measure serum IgG (b) and fecal IgA (c) antibody levels against bacterial COE. The representative results show the average OD results from five immunized mice. Error bars represent standard deviation