FIG. 4.
Changes in activity scores of ferrets immunized with a single inoculation of vaccine. (A) Ferrets were immunized with vaccines containing 30 μg of HA and either Iscomatrix adjuvant (IMX), AlPO4, or no adjuvant. Ferrets were challenged with the homologous clade virus 4 weeks later, and activity scores up to day 7 are shown. As a positive control, a group of ferrets was immunized with two inoculations of vaccine containing 3.8 μg of HA plus IMX given 3 weeks apart and challenged 4 weeks later. (B) Ferrets were inoculated once with 3.8-, 7.5-, or 15-μg doses of vaccine with either Iscomatrix or AlPO4 adjuvant. The activity was recorded and is presented as in panel A. (C) Nasal washes from the ferrets described in panel B, sampled on days 3, 5, and 7 postchallenge, were titrated in Vero cells. The limit of detection for this assay was 100.5.