Mouse vaccination and titre confirmation
To obtain consistently high anti-TeNT antibody titres, mice were vaccinated three times, at three-week intervals with 2 tetanus toxoid international units of human divalent diphtheria-tetanus vaccine (ADT, Seqirus). Immunity of the mice was confirmed by injecting a small subset of animals with 500 times the TeNT dose capable of inducing stage 4 tetany in naïve mice within 24 hours; no symptoms of tetanus were observed. The titres of all mice data included in the study were confirmed to be protective (>1:8000 (Fishman et al. , 2009)) by serum ELISA, three weeks following the final vaccination. Data for mice with non-protective titres (< 1:8,000, three mice) were excluded from the study and where appropriate the group size was changed from n = 6 to n = 5 (Supplementary data Table 1).