Figure 1
Schematic outline for of Vaccination and challenge. Two animals in Group 1 (G1: #4550 and #4552) were subcutaneously vaccinated with 106 CFU of ∆pdpC (gray inverted triangle) at −21 dpc, whereas four animals in Group 2 (G2: #4118 and #4548) and Group 3 (G3: #4549 and #4686) were similarly administrated the same volume of saline (white inverted triangle). At 0 dpc, the four animals in Groups 1 and 2 were challenged intratracheally with 106 CFU of virulent SCHU P9 (black inverted triangle), whereas the two animals in Group 3 were similarly administrated ∆pdpC (gray inverted triangle). The black arrows indicate the schedule of blood collection and measurement of body weight and temperature on −21, −19, −17, −14, −11, −7, 0, 2, 4, 7, 10, 14, 17, and 21 dpc. Two animals in G2 (#4118 and #4548) were euthanized at 11 and 7 dpc because of severe clinical signs. All animals in Groups 1 and 3 the survived the observation period were euthanized at 21 dpc.
