VHMW OAg produces a glycoconjugate vaccine conferring protection against intranasal challenge with a high dose of F. tularensis LVS. (A) Anti-OAg IgG ELISA units to the F. tularensis (Ft) LPS coating agent measured at day 49. Dots represent individual animals. Horizontal bars represent mean ± SD values. i.n., intranasal. (B) Survival of mice intranasally (IN) challenged with Ft (100-fold the IN LD50) after immunization with VHMW-TT, HMW-TT, LMW-TT, or Ft ∆kdhAB or administration of adjuvant alone. There were eight mice per group. **P ≤ 0.01. ns, not significant.