FIG. 1.

Purification of type s1/m1 and s2/m2 VacA antigens. VacA was purified from broth culture supernatants of H. pylori 60190 and 86-338 (lanes a and b, respectively), and the two preparations (standardized by protein concentration) were analyzed by SDS-PAGE and silver staining. Yields of VacA from strain 60190 were about 10-fold higher than those from strain 86-338; therefore, the VacA preparation from the latter strain was concentrated 10-fold by ultrafiltration with a Centricon-30 device (Amicon) prior to SDS-PAGE.