—To determine the significance of the Bordetella pertussis strain used as the antigen in the agglutinin assay for the evaluation of pertussis vaccines.
—Randomized, double-blind study.
—Health maintenance organization clinics, primary care clinic at a referral hospital, and private practices in Los Angeles County, California.
—Forty healthy infants.
—Twenty infants received whole-cell pertussis-component diphtheria-tetanus-pertussis vaccine (DTP), and 70 infants received acellular pertussis-component diphtheria-tetanus-pertussis vaccine (APDT) at ages 2, 4, and 6 months.
—The agglutinin assay was performed using three separate B pertussis strain preparations: (1) strains 130 and 138 in equal quantities, the constituents of the DTP vaccine, (2) strain 460, and (3) strain Tohama, the constituent of the APDT vaccine.
—The agglutinin titers were highly strain dependent; in both groups of vaccinees at both ages the Tohama values were highest, followed by strain 460 and then strains 130/138. The vaccine groups had comparable titers at age 2 months regardless of the assay antigen used. However, at age 7 months, after three immunizations, the DTP group geometric mean titer was more than 10 times greater than that of the APDT group using strains 130/138, but only 2.6 times higher using strain 460 and almost equivalent using Tohama strain.
—Vaccine group agglutinin value comparisons strongly depend on assay antigens used.(AJDC. 1992;146:1148-1150)