Fig 8.
(A) Evaluation of antibody titers in the sera of rats after active immunization with OmpA, Ail, Pla, and F1-V proteins. Individual animal sera were titrated in duplicate after serial 10-fold dilution. Preimmune sera were used as controls. The insets show the detection of the purified antigen using specific serum to a particular antigen (lane 1, by using preimmune serum; lane 2, by using postimmunization serum). (B) Active immunization of rats with F1-V and Ail provided protection to animals against developing pneumonic plague. The animals were challenged with the WT CO92 at a LD50 of 8.6. The data were statistically analyzed by using Kaplan-Meier survival estimates, and the P values are presented.