FIG 2.

B-H1 priming reduces mouse weight loss during H5N1 challenge. Mice were primed with B-H1, B-H3, or B/Yamagata/16/88 (wild-type) virus or administered PBS (n = 60/group). At 90, 180, 270, or 360 days after priming, mice were infected with H5N1 A/Vietnam/1203/04 (PR8 reassortant) virus at five different doses (10¹, 10², 10³, 10⁴, or 10⁵ PFU/mouse, n = 3 mice per dose). Weight monitoring was performed daily for 14 days. Weight is expressed as the percentage of initial weight at day 0 (100%). The mean ± standard error of the mean (SEM) (error bar) is plotted for each group.