Post-challenge administration of the human anti-F1 m252 mAb conferred better protection.

<p>The human anti-F1 m252 mAb was administered before or after <i>Y</i>. <i>pestis</i> challenge, and mice were monitored for 21 days after challenge. The mouse anti-V 7.3m mAb (100 µg) was used as a positive control mAb. Normal human serum (NHS, 500 µg), which was used as a negative control, had only 5 mice per group. The numbers behind each antibody represent the time in days in which the antibody was administered (500 µg) to mice relative to the day of challenge (day 0). The two numbers after the human anti-F1 m252 (−1 and +5) represent two different days when the mAb (500 µg) was added to the same group of mice relative to the day of challenge.