FIG. 5.

Effect of LPS vaccination and passive transfer of immune serum on numbers of B. bronchiseptica strains RB50, 1289, and RB50Δwbm. (A) C57BL/6 mice were either left unvaccinated (black) or vaccinated with LPS purified from strain RB50 (dark gray), 1289 (light gray), or RB50Δwbm (white). (B) C57BL/6 mice were given either naive serum (black) or RB50-induced (dark gray), 1289-induced (light gray), or RB50Δwbm-induced (white) serum and then inoculated with either strain RB50 or 1289. The bacterial load was quantified 3 days postinoculation. Numbers of bacteria are expressed as the average log CFU ± standard deviations. The dashed line represents the lower limit of detection. Asterisks denote P values of <0.05.