ANTIBODY AND CELL-MEDIATED IMMUNE-RESPONSES TO BOOSTER IMMUNIZATION WITH A NEW ACELLULAR PERTUSSIS-VACCINE IN SCHOOL-CHILDREN

235 healthy 10-12 years old school children were randomly immunized wi th either a booster dose of diphtheria-tetanus-acellular pertussis (dT ap) or diphtheria-tetanus (dT) vaccine. For this booster immunization designed for school children and adults, the quantifies of Bordetella pertussis antigens in the dTap vaccine had been reduced to one third o f those of the Infanrix(R) vaccine (SmithKline Beecham) commonly used for infants. IgG antibodies and cell-mediated immune (CMI) responses t o pertussis toxin (PT), pertactin (PRN) and filamentous hemagglutinin (FHA) were assessed by an enzyme immunosorbent assay and in vitro prol iferation of peripheral blood mononuclear cells, respectively. Before immunization, 55%, 80% and 99% of children rr had detectable serum IgG antibodies to PT PRN and FHA, whereas CMI response was found in 35%, 27% and 50% of children, respectively. After immunization, a 20-30-fol d increase in geometric mean level (GML) of antibodies to the pertussi s antigens occurred and CMI response to PT, PRN and FHA was seen in 88 %, 94% and 100% of children, respectively. Adverse reactions following the immunization were rare. The results show that booster immunizatio n with an acellular pei tussis vaccine with reduced concentrations of antigens induces both antibody and CMI responses and support further s tudies of this pertussis vaccine in school children. (C) 1998 Elsevier Science Ltd All rights reserved.