FIG 3.

Survival curves of the TF-SPF-vaccinated rabbits following systemic infection with the Vollum or Vollum ΔTox (Δpag Δlef Δcya) strain. TF-SPF (toxin-free secreted protein fraction)-immunized rabbits (4 groups of 4 rabbits) were infected i.v. with vegetative encapsulated bacteria of the Vollum (solid red) or Vollum ΔTox (solid blue) strains. As controls, immunized rabbits were infected s.c. with the Vollum strain (green) and naive rabbits were infected i.v. with the Vollum strain (dashed red).