FIG. 1.

Evaluation of different routes of administration by measuring induced antibody titers. Four groups of 5-week-old chickens were immunized with 10¹⁰ vp of recombinant replication-defective adenovirus encoding the hemagglutinin protein (Ad5.HA) of the influenza A/VN/1203/04 (H5N1) virus or control Ad5 virus. Ad5.HA was administered through the subcutaneous (sc), conjunctival (ocular), or intratracheal (oral) route. Sera from chickens were isolated at the indicated time points and tested in an HI assay using 8 HA units and turkey red blood cells. Results are shown as the log₂ value of the geometric mean (GMT) of each group.