Figure 6.

Toxin neutralizing capacity of mouse sera induced by ShigETEC vaccination. (a) Mice were vaccinated 3 times i.n. with 10⁸ CFU ShigETEC. Serum at indicated dilutions was incubated with indicated amounts of LT, and LT-binding to GM1 coated plates was measured. Bound LT was detected with a polyclonal anti-cholera toxin antibody. (b) Sera from individual mice (3 times i.n. vaccinated with 10⁸ CFU ShigETEC (blue symbols) or buffer (mock, black symbols) were pre-incubated with the 5 ng LT. LT induced cAMP release was measured in T84 human colon epithelial cells. (c) 5 ng synthetic ST was pre-incubated with pooled serum from mice vaccinated i.p. with LTB-ST_N12S (blue bar) or LTB-ST_WT (red bar) protein or vehicle (mock). ST-induced cGMP release was measured in T84 cells.