dmLT_Fig. 3. Recovery of dmLT after incubation at pH 3–7

Double mutant heat labile (dmLT) adjuvant is being proposed for oral vaccine formulation. Given the loss of dmLT observed with the HCl and simulated gastric fluid in Table 2 this experiment was conducted to determine the pH stability of dmLT. This work was conducted in two separate experiments. In the first experiment dmLT was diluted in pH buffers ranging from pH 3-7 and incubated at 4˚C and 37˚C. Samples were taken at the specified time points, neutralized and measured by ELISA. After determining dmLT was stable between the pH range of 4-5 a second experiment was conducted to look at finer pH intervals between 4 and 5. Again dmLT was diluted in pH buffers (4, 4.2, 4.4, 4.6, 4.8, 5), incubated at 4˚C and 37˚C. Samples were taken at the appropriate time points, neutralized and measured by dmLT ELISA.