Fig. 1.

Mice received two, three or four weekly intraperitoneal injections of A. simplex (100 µg), PT (300 ng) and alum (1 mg) in 200 µl of phosphate buffered saline (PBS) (Protocols A, B and C) (Fig. 1). Control mice received PT with alum or saline. Six weeks after the initial sensitization dose, a subset of mice was intravenously challenged with 200 µg of A. simplex in 50 µl of saline solution. A second group fasted overnight and was challenged with 2 mg of A. simplex by intragastric gavage. The mice were then observed for 2 h. Cytokines from stimulated splenocytes were measured on week 6 and 10.