Induction of tetany in naïve mice
The rate of tetany symptom development and the stage of tetany reached
was dose dependent. At doses of 0.01 ng of TeNT or greater, stage 4
tetany was reached for all naive mice (Figure 3A–C). Some variation in
the time taken for symptoms to develop was typically reported in both
vaccinated and non-vaccinated mice. Decoy administered to naïve mice, at
a 100 µg equimolar dose, did not induce any symptoms, confirming the
decoy is unable to induce tetany. TeNT administered at doses of 0.01 ng,
0.1 ng and 1 ng, in combination with 100 µg of decoy, were considerably
less effective than TeNT administered alone (Figure 3A, B and C). This
would suggest an inhibitory effect of the decoy, possibly due to
residual binding activity of the TTc R1225E W1288A component preventing
neuronal binding of the active toxin, either by flooding receptors or
through steric hinderance.