FIG. 1.

Western blot analysis of the antigenic profiles of wild-type and mutant B. pertussis strains. Whole-cell lysates of the indicated strains grown under nonmodulating (Bvg⁺ phase) conditions or modulating (Bvg⁻ phase) conditions were separated on an SDS–4 to 12% gradient polyacrylamide gel, transferred to polyvinylidene difluoride, and probed with serum from a child recovering from pertussis (A) or anti-VraB antibody (B). The positions of the molecular weight markers (in thousands) are shown at the left. WT, wild type.