Figure 3. Induction of comet-reducing antibody.

The sera described in Figure 1 obtained from mice immunized with A33 and L1 (AL) plus the indicated adjuvants were used to detect antibodies that inhibit the formation satellite plaques due to spread of EV in liquid medium. BS-C-1 cells were infected with VACV strain IHD-J (80 pfu/well), overlaid with medium containing a 1:50 dilution of pooled mouse serum, and 40 h later stained with crystal violet. The column labeled pre-challenge represents samples collected three weeks after the second immunization and one day prior to intranasal virus challenge. The post-challenge column shows samples collected from surviving mice two weeks following challenge. The well shown in the upper left corner shows the typical formation of comet-shaped plaques in the absence of serum