Long-term pertussis-specific immunity after primary vaccination with a combined diphtheria, tetanus, tricomponent acellular pertussis, and hepatitis B vaccine in comparison with that after natural infection

The aim of this study was to compare pertussis-specific humoral and cellula r immunity in children 5 years after a primary vaccination with a combined diphtheria, tetanus, tricomponent acellular pertussis, and hepatitis B vacc ine (DTaP-HBV; InfanrixHepB; SmithKline Beecham) with immunity after natura l infection. The subjects were 38 children aged 5 to 6 years who received D TaP-HBV at 3, 5, and II months of life and 21 subjects of similar ages and sex who acquired pertussis in the first year of life. Immunoglobulin G (IgG ) antibody titers against Bordetella pertussis antigens, peripheral blood m ononuclear cell-specific proliferation, and the secretion of cytokines were evaluated. After 5 years, only a small proportion of vaccinated and infect ed children had significant specific concentrations of Ige in serum against all three B, pertussis antigens, and T-cell responses persisted in a minor ity of subjects. A preferential type I cytokine response with the secretion of gamma interferon was observed in the pertussis group, whereas a type 2 skewed response was observed in the vaccinated children; however, the quant itative differences in the cytokines produced by DTaP-HBV and natural infec tion were minimal, In conclusion, our results show that the immune response s induced by primary pertussis vaccination are qualitatively and quantitati vely similar to those seen in children who recovered from natural infection and highlight the need for booster immunization with pertussis vaccines in order to maintain adequate levels of a specific immune response to B. pert ussis.