FIG. 1.

Kinetics of anti-PA Ab generation after primary and secondary immunization. PA-based vaccine doses of 1 μg (solid lines) and 25 μg (dashed lines) were injected (in 0.5 ml s.c.) into 20 guinea pigs. Fourteen weeks after the immunization, the animals were boosted with the same PA-based vaccine dose. The kinetics of Ab generation in these 20 guinea pigs were monitored during the first 14 days after the primary immunization (A and C) and after the booster (B and D), as described in Materials and Methods.