FIG. 5.

Minimal effective dose of anti-A33 6C for protection in mice. Groups of five BALB/c mice were inoculated intraperitoneally with 90, 45, and 22.5 μg of purified IgG or 5 mg of VIG. Twenty-four hours later, mice were challenged i.n. with 5 × 10⁴ PFU of the WR strain of VACV. Mice were weighed individually, and mean percentages of starting weight ± standard error were plotted. Controls were unimmunized (no antibody) or unchallenged (no virus). †, died naturally or killed because of 30% weight loss.