FIG 5.

Production and secretion of LT by ETEC strains expressing LT1 and LT2 variants as determined by quantitative GM1-ELISA. (A) Total production in LT1 and LT2 strains. (B) Comparison of LT production in LT1 and LT2 strains using the sonicated bacterial (Pellet) and supernatant (Sup) fractions. (C) Percentage of LT secretion. Results are means from duplicate independent tests of each strain. The statistical analysis was performed by the Mann-Whitney test using Prism, version 6.00. Horizontal lines indicate median values. *, P < 0.05; **, P < 0.01; ***, P < 0.001; n.s., not significant.